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Control options with Vitodens 200 WB2B (Vitotronic 200 + Vitotrol 300)

24

Comments

  • ChrisChris Posts: 2,869Member
    No He Doesn't

    Would just need to get a Vitotrol 300 which an extension of the boiler control and about the same cost as a Honeywell Prestige Thermostat...
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    No I mean for the Loch...

    The boiler can except a 0-10v modulation signal from say a Tekmar or Honeywell unit.
    · ·
  • smihailasmihaila Posts: 93Member
    And now

    maybe we can get in more understanding of what Vitotrol 300 is doing?

    How is the vitotronic 200 downstairs making use of the built-in temp sensor? Used only to shift the curve up or down? Or if I grab a real thermometer, after a few cycles, I'm going to read the same temp as what Vitotrol 300 was set to, as setpoint temp? Is the temp set through that only a 'hint' ?



    Thanks.
    · ·
  • smihailasmihaila Posts: 93Member
    edited April 2013
    0..10V input signal

    True, but that would be doing a rather more complex thing. It will basically make the Viessman act like a slave and modulate at the rate proportional to that DC input voltage.

    Chris is right, one should see that as serving another purpose. Because we don't want to give up the built-in control/intelligence of the vitotronic 200, as far as a 'ODR driver' is concerned.



    (sorry, I was referring to Viessmann's case - note that Viessmann has that too).

    But in Lochinvar's case, it can be done easier - just by using one or all three thermostat inputs. Again, if the Knight will consider those signals as "high temp limiters' and not affecting blindly the odr-driven logic, then it's fine.



    Who knows, to me Vitotrol 300 is still mystery. Maybe it does what's supposed to do (high limiter) but the docs are not explaining it enough. We have to get the input from someone who actually owns it. If that's the case, then my apologies for being too circumspect/paranoid :-)
    Post edited by smihaila on
    · ·
  • ChrisChris Posts: 2,869Member
    The Vitotrol

    Is an extension of the boiler control with the feature of giving the boiler indoor temp feedback which the boiler uses to adjust it's curve based on the outdoor temp, indoor temp in adjusting the supply water temp.



    With constant circulation and panel rads with TRV's it is a homerun. The only issue is the low end btu/hr. It doesn't fit your application unless you want to invest in a Caleffi ThermoCon 25 Gallon Buffer tank in lieu of the LLH.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    · ·
  • SWEISWEI Posts: 4,534Member ✭✭✭
    high temp limiters

    Work just fine, but occupants need to be educated (and usually reminded) of their function.  Leave them ~2-4ºF above the indoor design temp and then carefully tune the curve.  Mind the deadband on the stats -- it can really mess you up.
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  • Paul48Paul48 Posts: 2,194Member ✭✭✭
    smihaila

    I'm curious as to how long you would think that the boiler should be shut off for? The boiler would be attempting to provide just enough heat to compensate for the loss from the structure. It can't be more efficient than that. You would be interfering with that, causing the sytem to cool, and then cause it fire higher than normal when it restarted, and sacrificing efficiency. It is not a snapshot, it's a dynamic process.You seem to think the boiler would over-heat the house, and that is just not the case. You keep applying "Old School" thought processes to this new technology.
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  • smihailasmihaila Posts: 93Member
    It can't be

    that I am applying 'old school' to this technology. Simply because it's been only 9 years so far since I'm here in Canada :-) I was born, grew up and educated back in Europe. So, I grew up mostly with the constant circulation use case. At least in my parents' apartment. But to be honest, I do recall that the pump (integrated in a Vaillant) was not running all the time - after the fire ceased, it was running for 5-10 minutes (I guess because it's still having water good to be moved around, to transfer energy in the rads). And then it stopped. Without any on/off external thermostat of any kind.



    My question about fire/no-fire rates is in this context - to explain it better: I see no issue in the boiler firing for very long periods (even non-stop) - if, and only if - according to the estimated load/ODR, it can modulate the valve gas as lowest as possible to achieve that target. Not more, no less. To achieve optimum fuel consumption (well I guess that corelates also with condensing range and other efficiency factors).



    IF it's a bit warmer outside, or the heat inside the house doesn't lose at the estimated speed and stay more inside, then my assumption was that the boiler wouldn't be able to modulate so low (i.e. less than 30%?). If it can stop in that case, FINE. If want to put more heat in, it will be wasting fuel, am I missing something?
    · ·
  • smihailasmihaila Posts: 93Member
    Great

    Excellent, so you are happy with your current setup, and what the vitotrol indicates, with a proper heat curve selected (based on a trial-and-error long term observation), it will roughly indicate the same as a thermometer in that room?

    Thank you Chris for explaining it.
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  • GordanGordan Posts: 873Member ✭✭
    What you're missing...

    The boiler's ODR control will, when properly adjusted, tell the boiler to maintain just the right supply water temperature to allow your emitters to compensate for the heat loss - no matter how small the heat loss. If there's no heat loss - that is, the outdoor temp is close to or above the desired indoor temp - warm weather shutdown kicks in, and space heating (including space heating circulator) will turn off.



    The boiler's burner modulation control will, if possible, maintain the correct firing rate to keep the supply water temperature at the setpoint that the ODR control tells it to maintain. If it can't turn down low enough, it will turn the burner off completely for a little bit of time in order to provide, on the AVERAGE, the supply water temperature equal to the ODR setpoint. While the burner is turned off, the circulation continues, as it should.



    So, let the boiler's controller do its job. The only reason to have a thermostat is to make up for the case where your ODR curve is set too high for the conditions. Basically, it's a very crude and one-sided form of indoor feedback (can't bump up temperature in case the ODR curve is too low, for instance.)
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    hi smihaila

    Are you making any progress smihaila?
    · ·
  • smihailasmihaila Posts: 93Member
    edited April 2013
    yes

    Gordon's last post about how the boiler reacts to the odr and indoor feedback is more encouraging.



    The only part that still puzzles me is this statement: "If there's no heat loss - that is, the outdoor temp is close to or above the desired indoor temp - warm weather shutdown kicks in, and space heating (including space heating circulator) will turn off."





    So, shall I understand that there won't be any situation whereas the outdoor temp is still considerably below desired target indoor temp, and the boiler will be impossible to be in "turned off" state? This would mean the following: The boiler is able to adapt to the hot water needs so well (no matter how big difference between outside and inside), that not only it can maintain a firing rate, but ALSO with the most optimal volume of gas being burned (even in low modulation)? If that's the case, then it's amazing.

    Maybe Gordon's example was on the extreme side (when we get into WWS mode). And in reality the boiler should, and can, stop also in other situations. This would be in sync with the next statement: "If it can't turn down low enough, it will turn the burner off completely for a little bit of time in order to provide, on the AVERAGE, the supply water temperature equal to the ODR setpoint." That's fine with me if it's like that.



    The only "oddity" is the fact that, during the fire-off period, the pump will always work, instead of, let's say, working only 3-4 more minutes since the moment of time the boiler ceased firing. Because what purpose serves to recirc water which in the meantime gave up all its heat energy into the rad circuit and now it's cold? That's how I remember it working back in my former apartment anyway.







    I am ok with ODR, I find it in fact the answer to the temp fluctuations and 'holes' that I am now having with my strange forced air blower. And (besides the pump) I'm puzzled about the recent impression from people across the pond, who are saying that their fuel consumption average is still lower when they complement the odr setup with a thermostat....:-) It's funny, because they say that they are happy sometimes with the boiler firing less often but working for longer. Maybe they are referring to the warm temp case (spring or autumn). Otherwise it doesn't make sense, unless there is something wrong with their boilers and can't modulate low enough and waste small fuel volume.



    Just to give you an example: right now, at in Central/Eastern Europe is kind of warm. And a guy was very happy that in his apartment the boiler was firing only 4 or 5 times per day and when it was firing, it kept firing for about 45 minutes to achieve the target temp. Imagine that he was very happy - he tested the both scenarios (continuous run, no thermostat vs. his latter approach) and he said that we was able to drive the consumption down to as low as 2-2.5 cubic meters of natural gas per day :-)
    Post edited by smihaila on
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  • ChrisChris Posts: 2,869Member
    Guys

    He is wasting all of our time, effort and advice. He's called everyone he can to try and get a boiler as cheap as he can. Suggest he finish where he started with ecomfort.com. Yes my vines run deep and you cannot dig deep enough to get away from the roots.



    Like I recommended prior. Go buy a Lochinvar Knight WHN-55. It would be in your best interest and honestly ours..
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
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  • smihailasmihaila Posts: 93Member
    sorry

    if that was the impression that I have left. I admit that I am a bit stressed out, as I need to balance between my stresfull day-to-day job and also this project.







    Sorry if I have offended anyone - it was never my intention.

    Thank you all for your help and advice. I believe I have a better understanding now, thanks to you.

    [I'm not trying to be cheap, I'm just looking for a good value for my money. We are a modest family of 4, with myself the only breadwinner in the house. I have no car, going to work by bus or bike. But no mortgage and no debt at all. This without any help from anyone - we don't even have any relative here. We try to leave withing our means, and saving as much as you can from these greedy Governments and banksters]
    · ·
  • ChrisChris Posts: 2,869Member
    Value?

    Your looking for free education to purchase from an internet peddler. Your not looking for value because if you were you'd pay for it. Your questions go way beyond someone looking to make the right decision. Your pushing for a design and control strategy.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
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  • EastmanEastman Posts: 616Member ✭✭
    edited April 2013
    on/off and indoor feedback

    Smihaila, your experience in Europe with hydronic heating is probably not comparable to a system using indoor feedback.  Indoor feedback systems are a major step up from central on/off thermostats.  They are still quite rare and I think it is unlikely you would have any direct experience or spoken with someone that had such a system.  Most indoor feedback systems are very precise.  Much more than an on/off thermostat.  They also tend to be much more sophisticated.  I would be quite surprised if the Vitodens could not manage its firing cycle correctly during any part of the season.



    Your concerns are valid though, and many European systems may indeed benefit from the addition of an on/off thermostat, but an indoor feedback system would be even better.



    In a nutshell:  electronic dynamic ODR + indoor feedback thermostat is much better than user adjusted ODR + regular on/off thermostat.



    Let me clear up some issues:



    #1

    "The only "oddity" is the fact that, during the fire-off period, the pump

    will always work, instead of, let's say, working only 3-4 more minutes

    since the moment of time the boiler ceased firing. Because what purpose

    serves to recirc water which in the meantime gave up all its heat energy

    into the rad circuit and now it's cold? That's how I remember it

    working back in my former apartment anyway."



    I can't speak for the Vitodens, but pump settings are almost always configurable.  You can set it to run constantly, turn off right away, or run for a little bit of time after the flame cuts off.  Keep in mind that the electrical consumption of a modern single pump residential system is extremely low  --probably less than the boiler's electrical power requirements.  *But*  In most systems it is *not* advisable to install the Vitodens without an LLH.  This boiler uses a water tube HX that has quite a bit of hydraulic resistance.  It is quite likely that you will have to use some type of P/S arrangement.



    #2

    "So, shall I understand that there won't be any situation whereas the

    outdoor temp is still considerably below desired target indoor temp, and

    the boiler will be impossible to be in "turned off" state eventually?

    This would mean the following: If it can maintain a firing rate even in

    VERY LOW modulation conditions and thus it burns the optimal volume of

    gas, even in such extreme conditions, then my hat off !



    The Vitodens can barely modulate low enough for your project.   This is a major concern because modulation is arguably the key to making all of the other features of this boiler work as intended.  The boiler would be forced to toggle on and off for the majority of the season, despite its sophisticated feedback control system.  It would perform well "on the average," but a system that could modulate much lower is desirable.  Keep in mind that the goal really is to keep the burner on as long as possible.  Matching supply with demand on a continuing real time basis is the ideal, both for efficiency and occupant comfort.



    #3



    "It's funny, because they say that they are happy sometimes with the

    boiler firing less often but working for longer. Maybe they are

    referring to the warm temp case (spring or autumn). Otherwise it doesn't

    make sense, unless there is something wrong with their boilers and

    can't modulate low enough and waste small fuel volume."



    Their boilers can not modulate low enough.  In this situation an indoor feedback system should provide identical (if not better) fire cycle management.
    Post edited by Eastman on
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  • GordanGordan Posts: 873Member ✭✭
    I didn't take it that way, Chris

    It's a different world we're living in now from the one in which we grew up. Information (whether true or misleading) spreads much more rapidly. I think we'd be lying if we said that we've never benefited from someone (or ones) sharing knowledge freely - heck, seems to me that this is what this site, and others like it, is all about. I don't think that the OP is looking for someone to design his system for him, he's groping for understanding of how things work. You've been very generous with sharing your knowledge, but know your limits and don't participate beyond the level with which you're comfortable. Internet peddlers are here to stay. As, I believe, are knowledgeable and adaptable distributors who provide real added value to justify their markups.
    · ·
  • GordanGordan Posts: 873Member ✭✭
    Well, sure...

    When you're externally turning off the boiler for a period of time, in essence you're using the thermal mass of your home as a buffer. The only benefit of this that I can see would be to, in essence, lengthen the firing cycles, but there's a catch. The boiler does not directly heat the space; it heats the water that heats the space. So, not only does your average water temperature have to be high enough to cause overheating, which would then trip the thermostat into shutting off heat demand, but it actually has to be high enough to cause the emitters to shed enough heat into the space to equal the minimal burner modulation of the boiler. Otherwise, the boiler will still cycle its burner as the water temperature will of necessity exceed the setpoint.



    I still think you're not getting the basic idea behind burner cycling. The ODR just determines the water temperature setpoint. Call this the "floating" setpoint, whereas non-ODR boilers have a "fixed" setpoint (whether the control is a simple aquastat or a more sophisticated PID-type control.) The boiler will circulate as long as there's demand for heat (from a thermostat or other control, or constant.) The boiler will FIRE until supply temp reaches setpoint + differential. Then the boiler will shut off the burner until supply temp reaches setpoint - differential. The reason there is still circulation is because there is still useful heat in the water - it is maintained at a setpoint. Below minimum modulation, EVERY boiler is just an on-off boiler.



    Now the basic question becomes: does the loss of efficiency that comes from higher average supply (and return) temperatures outweigh the loss of efficiency that comes from the boiler cycling its burner for shorter intervals? My hunch is that there's some sort of break-even point, depending on the system. It could very well be, however, that the differences would be minuscule.
    · ·
  • smihailasmihaila Posts: 93Member
    edited April 2013
    "Peddlers"

    Guys, perhaps you are spoiled over there, in US. In the sense that it's a more open market, with a lot of competition, also more transparency maybe.

    Maybe you don't know how it is here in Canada. In my perception, everything is opaque, with huge markup prices, lack of real interest from contractors for doing a good job but instead getting it as cheap as they can, but with big profits for them. They do not even have patience in designing intelligently a pipe route in the house etc. Only the commercial projects look great, for the residential customers it's just a quick money scheme. Again MY impression only.

    If those contractors (which I HAVE contacted - three of them) were offering more reasonable prices for my (small) job, I would've gladly gone with them. Would you like to know how much did they ask for a job involving Vitodens 100 only, no indoor temp feedback, one zone, pex pipes, no LLH, no high-eff/ECM pump and 11 under-dimensioned pesky radiators?? They have asked me twenty-five thousand dollars, plus 13% sales tax. Do you consider that reasonable? When I could do the same with my father maybe for around 10k$, and with better equipment such as the Lochinvar WHN51 or the Vitodens 200 and with proper sized radiators!. Heck, they didn't even CARE to do a Manual-J calculation - they have said that they would assume any risk, and once I would sign the contract, the will do some calculations, and if there is less need for materials or rads (less than their ballpark estimate), I would NOT receive anything back as compensation. I had to buy the HVAC-Calc software license myself and the all the calculations solely.



    Tell me, is that reasonable? And Chris, you are calling those folks from eComfort or pexsupply.com "peddlers". I am fully aware that they are just poor intermediaries - they sometimes are not even carrying anything in stock, but just facilitate the exchange of hands for the goods, and no manufacturer's warranties whatsoever. BUT, I see some values added by this companies, and I would really appreciate if such model could spread out more. Let me explain why: because they add PRICE TRANSPARENCY in the eco-system. In aca-nada we lack transparency and competitive markets completely. Heck, I feel myself like living in a feudal state (which doesn't even have a president, but only a prime minister). In other countries, US included, you can get into brick&mortar plumbing+hydronics stores almost at each foot step. You can actually go in and put your hand on a boiler etc...Here in Canada there is no such thing (at least couldn't find that yet). To me, the very fact that a store like ecomfort.com exists, and it can also help with the shipping and requires only some minor effort on my part (i.e. dealing with customs and brokerage), is a balloon of oxygen.



    I know it's not the ideal model - again, if the contractors would be more reasonable and down-to-earth and not greedy for money, this situation wouldn't have happened. I always appreciate hardwork and giving proper compensation for a work done well. But for these Canadian leeches, I have only bad words to say about them.



    And yes, consider me a "Internet peddler" - I won't be upset. At least, as Gordon admitted, the Internet has contributed to many good things, and favouring rapid exchange of information. Destroying the opacity - I know that lawyers, doctors, and other jobs of trades, HATE this transparency, because it gives people more power and freedom in understanding things and taking more opinionated decisions.

    And, after all, I came to this web site because it is called ... HEATING HELP...It was not called "help for the heating PROs", right? Why do you have to be so arrogant, Chris? If it's one attitude that I don't like in general, it is the arrogance.

    To me, living in Canada, each day, is a lesson of trying to humble myself even more. Is it good, or bad, don't know. But I hate arrogance.



    Maybe you were trying to explain things in a certain way, in a more subtle manner, and between you, that looks like an intelligent/meanigful answer. Maybe I'm not smart enough to understand your subtleties. Or maybe you are trying to defend a sort of mainstream idea for Vitodens.

    But when I try to ask something very bluntly, such as "can Vitodens 200 control a system pump" and not only during "warm weather regime", or what vitotrol 300 really does, you are always trying to answer very indirectly, such as "go get the Knight instead", never admitting black on white that Vitodens 200 was thought for a certain use case - constant circulation.

    Mr. Eastman's last post - it was more than welcome, sounded like dis-interested and very helpful answer. I really appreciated it - thanks to him I understand now. Also, Gordon's help was more than welcome.

    I was not trying to get a 'design for free'. As Gordon said it, just trying to have a better understanding of the stuff first. I am an analytical person in principle, sometimes even too much. Eastman explained very black and white, finally, why the LLH or other form of separation is quite a must with these Viessmann models. And that there may be other companies/models which do not have this restrictions (initially I thought it's rather something like a 'safety measure' like a 'just in case' factor from Viessmann).

    I also understand NOW, why back in Europe, you cannot find Viessmann 200 models being sold with powers less than 45kWatt. It's because only for models higher than that, they require the presence of the LLH, otherwise the warranty is not honoured. And since people over there don't like to use it, the sellers simply decided not to put lower models on the market. For lower powers, they will sell only combi models.
    Post edited by smihaila on
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  • smihailasmihaila Posts: 93Member
    Clear

    Dear Eastman, thank you, thank you and thank you ten times. For clarifying more on these ODR and modulation aspects. I was hoping that by going with the lowest Vitodens 200 model, the boiler would be able to modulate reasonably and no short-cycling. With or without a LLH. You are a 2nd source confirming that the WB2B-19 may not be appropriate for my need. It's funny though, how come ALL of those three local contractors (reputable companies, I can give names!), they have recommended the Vitodens 100 model (the one going up to 97 kBTU). Even if one of those 3 was somehow able to have an ballpark estimate for the heat load.



    I understand now - that maybe I'm too anal about the "boundary/extreme conditions" as far as the ODR is concerned. And, with a properly sized boiler, the boiler should be able to modulate down (i.e. burn the gas at moderate volume) even when the outdoor temps are starting to get close to the indoor.

    And you are right about the "feedback" that I have got from those people in Europe, about their "conclusion" about the on/off thermostat bringing cost savings down. Indeed, their boilers may be cheaper (Central and Eastern Europe usually goes with lower-end models - people can't afford something expensive, and there is an invasion of OEM products, made in Turkey or other less than ideal countries etc). So, their boiler may not be able to modulate down enough, with "finese".

    It's funny a bit - when I have started this project, I wanted to go for the ODR idea, definitely. Because I knew how the other, "normal american" system is and wished to stay away from that. But somehow, in the middle of the road, I got sidetracked by other more recent opinions from other persons. And since nowadays Europe tends to do stuff like in Americas and Americas vice-versa (i.e. I gave the example with America switching from copper to pex, while Europe is doing it opposite), somehow I thought that those guys and their thermostats are on to something. But now I understand.

    Keep in mind that I tried to remain open minded, not promoting a sort of fanatism towards ODR. Somehow Chris simply looks offended when somone questions these new 'principles'. Maybe to him something coming from Europe and especially 'German engineering' is some sort of sacrossant thing. To me, it's neutral, I dare to bash both European and American products, if they are stupidly made (not that this would be the case). I try to stay objective. German stuff is not always good. I've dealt with some cordless phones designed and made in Germany, in the past, and they were absolutely idiotic in terms of user interface. Everything full of registers and hidden setting. A sort of geeky stuff (I do appreciate geek stuff, being a software developer). But it was moved to extreme.



    Eastman, the only thing that may come to a bit of surprise to you is that the assumption about "I can't speak for the Vitodens, but pump settings are almost always configurable.  You can set it to run constantly, turn off right away, or or run for a little bit of time after the flame cuts off" - doesn't seem to stand true for WB2B and its power/pump module. The way I understood it (always indirectly!) was that only for the boiler pump, not the system pump is capable of that, and that only if a LLH+immersed temp sensor is installed.



    And yes, if we go with an ECM type of pump, the power consumption would be quite reasonable, even with the pump always on or with the speed reduced (as in case of a Delta-P or Delta-T pump - too bad that we can't get the Bumblebee yet).

    Thanks again for the logical and direct explanation.

    All in all, I find it extremely strange that the Viessmann folks didn't make a 200 boiler model available, to suite even lower loads, like mine (35-40 KBTU). My forced air furnace (16-year old, a "Heil") is sized for 50 KBTU. I don't understand why the contractors strives roughly for the double of the real max heat load. Is that a sort of magic formula, which applies only to forced air?
    · ·
  • smihailasmihaila Posts: 93Member
    Indeed

    "When you're externally turning off the boiler for a period of time, in essence you're using the thermal mass of your home as a buffer. The only benefit of this that I can see would be to, in essence, lengthen the firing cycles, but there's a catch. The boiler does not directly heat the space; it heats the water that heats the space. So, not only does your average water temperature have to be high enough to cause overheating, which would then trip the thermostat into shutting off heat demand, but it actually has to be high enough to cause the emitters to shed enough heat into the space to equal the minimal burner modulation of the boiler. Otherwise, the boiler will still cycle its burner as the water temperature will of necessity exceed the setpoint. "

    Exactly, it is as if those people reporting on those strange experiments, and shutting the boiler for long periods, combined also with long re-fire periods, were getting into a 'sweet spot' situation - making the boiler modulate stronger but - paradoxically - with less total fuel per day than in the other case. Indeed, maybe when they do that, they create a proper matching between the modulation capability of the boiler and the house heat demand.



    It is as if they mistakenly install way too powerful boilers (which is not un-realistic, because not too many over there do proper heat load estimates and also the types of house constructions over there are very diverse i.e. concrete, brick/mortar, also there are many flats/apartments as opposed to detached houses). And by letting such powerful boxes (i.e. 26kW or even 35kW) run in "odr" mode, they will shortcycle and each startup will obviously ask for more gas to be burned temporarily.

    These boilers are easily accessible over there. Many people are even learning and installing themselves. At about each 1-2 kilometers, it's impossible not to find at least one HVAC specialized store, where you can actually touch and buy directly. Not via accountants and price quotes and 2-3 weeks orders. Everything is right in front of your eyes. You go to a store like homedepot (or even smaller), you grab the device in your car and off you go :-)

    Mind you, we shouldn't go into the other extreme, as it seems to happen here: where everything is ultra-'regulated' and ultra-cautious and the business doesn't move, if you know what I mean. Too bad that there isn't too much demand for hydronic systems here, to make the market more diverse.



    Thanks for clarifying.
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    Statistically...

    most systems are twice the size they need to be.  This wouldn't be a problem if they could modulate all the way down to 0.  But most systems can only drop to a minimum of 20% of full fire  --a 5:1 ratio is very common in North America for hot water boilers.  I actually think the modulation ratio may be worse in Europe due to stricter emissions requirements  --something more like 3 to 1 for residential equipment.  (Someone correct me if I'm wrong.) 



    Chris suggested the WHN 55.  This has a minimum mod. of 11,000 btus.  (I know you're a kilowatt man but I just can't do it.)  There are models that can go slightly lower, but the WHN 55 is probably more forgiving of DIY mistakes due to its firetube HX.  A P/S arrangement is recommended but not really necessary if you do your homework.  It does not come with indoor feedback though.
    · ·
  • smihailasmihaila Posts: 93Member
    I'll try

    sourcing the WH055 first, preferably locally. And if I can't find it I'll have to go with the WB2B-19 and LLH. In that latter case, maybe I'll have to add a rad even in the un-heated garage (which is empty without a car LOL), just to increase the heat lot and avoid using that buffer which Chris was mentioning about.



    About the modulation ratios, I recall someone posting something about an interesting boiler model (IBC), which was able to achieve unusually high X:1 modulation converstion ratios - possibly due to more "liberal" testing and assessment procedures.

    I have found a Lochinvar local representative, and he was a bit puzzled as to how for a 1800sqft house (of which 500sqft is the basement) such small model is needed (39,000 BTU) :-). He was asking for room measurements / I have sent him my hvac-calc figures and we start from there.



    Thanks again
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    smihalia

    Adding rads in the garage is like filling your soup bowl all the way up even if you are not hungry.  At a fundamental level, any boiler that can not modulate below your maximum heat loss is a poor choice.  One could argue that you should just get a fixed output model then.  Surely there are other options that you have access to?



    You mentioned you have a 50,000btu furnace.  Is there something wrong with the current system?
    · ·
  • smihailasmihaila Posts: 93Member
    edited April 2013
    The forced air furnace

    Is 16 years old (which is also the age of the house). It's burning about 270 cubic meters/month during high peak winter season. The electric blower is drawing 800watts/hour. And there is no comfort at all. The furnace doesn't fire too often and after firing, it gets cold in the house quickly. The Honeywell 'programmable thermostat' is set for 23 celsius, and sometimes it doesn't seem to register the right temperature. When I feel too cold in the house, I just have to raise the thermostat manually from 23 to 25, just to make it send a heat demand. And then I move it back to 23 (and will still run). Just to have the stuff working.



    I tried the best I could to increase the comfort - installed R-50 sprayed polyurethane close cell insulation in the attic, installed a steel roof, replaced all the windows with European tilt-and-turn windows, triple glazing, Trocal uPVC 70mm profile, low-e, argon, Uw at about 1.0-1.2 K/m2. Everything with hard earned cash, no credit.



    And still cold. Most part of the "hot air" gets lost on the route from the basement to mainfloor. The air just raises up and stays close to the ceiling. Also the master bederoom is facing North and situated above the garage. The garage has no proper insulation for the outside walls, also for the part of the ceiling that gets outside the house. Also, the air duct that comes to the master bedroom, crosses all the length of the garage. Go figure.



    I hate the forced air systems with passion :-)
    Post edited by smihaila on
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    Have you investigated...

    variable speed furnaces?  I believe there are models that can modulate both the flame and blower.  These units are also quite amicable to various zoning systems and are capable of achieving much more precise temperature control.  Such an upgrade would almost certainly be less than installing an entirely new system.
    · ·
  • ChrisChris Posts: 2,869Member
    My Limits

    Gordan. My limits on Viessmann go beyond what is in the manual. In the political correctness I won't get into how many and who this OP has called to try and buy the boiler from. I understand the internet and deal with it every day. I agree, we all share and give our help. Should it go to the point where we give the inside information on the product to take a job away from contractors such as you?



    I still believe in protecting the trade contractor and when it comes to Viessmann, because of it's limited distribution and limited trade understanding, it's one of the last boiler lines the consumer has yet to be able to tap into from a functionality and control standpoint. I don't mind helping an end user after an install and go the full Monty but in the non installation phase your right. Not comfortable with giving the key to the city.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    · ·
  • gennadygennady Posts: 521Member ✭✭
    edited April 2013
    DIY

    I feel quite humiliated while reading all this mess. We have here DIY fer who decided that plumbers are charging too much for their knowledge and expertise and years of experience and decided that build heating system is not a big deal. Just buy boiler and install few pipes. Meanwhile lets ask some quick questions on this and I m sure some other forums. Then do it. I installed heating systems at houses belonging to heads of major corporations, banks and also people who I know probably hardly even could afford these systems as well. And all of them showed respect to what we did. Rarely I see such luck of respect as in this tread. What would mr. Michaila say I I would start developping software when i need one? Would he go same distance as was done here. Just my 2 cents.
    Post edited by gennady on
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
    · ·
  • ChrisChris Posts: 2,869Member
    Precisiley

    Why I walked away from this thread. Especially knowing he's contacted everyone under the sun to get the boiler as cheap as he can.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    · ·
  • greenygreeny Posts: 14Member
    Read the directions knucklehead

    200 and Vitotrol do everything your asking. Coding 2 - see Vitotrol influence factor and about 6 different system/boiler pump stop options. Thats all im tellin ya. When i used to ask how to use these unique features i got the keep it simple stupid. Had to figure it out myself. I have installed dozens of Vitotrols on single zone gravity or forced retrofits. If you install a Vitodens 200 its the cheapest communicating t-stat on the market! NA may be getting the better modulation of the UK Vitodens along with the new Vitotronic control this summer. Now go hire a professional.
    · ·
  • smihailasmihaila Posts: 93Member
    Not true

    Gennady, I have never said that it will be me (the software guy) doing the install. It will be my father, who's been doing more than 30 basic installs like this one. Please stay close to truth and don't be arrogant. You say that you did this and that, but honestly you still didn't seem to know how the PMP module in vitotronic 200 works :-).

    And to answer Chris' last message, if buying something through an online store, or asking a few things on how the Viessmann 200 works (or the ODR principle in general), is considered 'being cheap' (as opposed to attempting to contract the whole install via a local company) and trying to put at good use my father's skills (while trying to see what other differences are involved in general with the North-American ways of doing installs), yes, it's 'cheap'.

    Look, I appreciate everyone's input. The project is in 'go' status - the rads are about to come in one week. And the boiler - we're waiting for quotes for both the Knight and the Viessmann. I'll keep you guys posted with some pictures (if you are interested) with the install.

    Thank you.
    · ·
  • smihailasmihaila Posts: 93Member
    Thanks

    About coding 2 and " 6 different system/boiler pump stop options. " -- maybe I haven't read carefully enough the service manual - but everything there about system pump stop options was either related to mixing valve operations or when the 143 "external demand"/"external blocking" options are being used.

    If what you say is true, and coding level 2 will be able to configure the system pump to stop when no mixing valve or plug 143 is used, then it will be excellent.



    Thanks again.
    · ·
  • GordanGordan Posts: 873Member ✭✭
    Ok, you lost me

    You've come here to learn about heating systems, but honestly, it seems to me that you should learn a bit about grace, too. To come somewhere with your hat in hand and then lash out at people who have provided valuable information to you (albeit apparently not as much and not as quickly as you feel you're entitled to) is bad form. My impression is that Gennady, for one, has forgotten more about what you came here to ask about than you'll ever know, or care to know. I did not feel that there was anything wrong with you asking questions or even doing this project yourself if you felt up to it, but I am taken aback at the argumentative attitude. Please stop it. You're here asking for favors, so act like it.
    · ·
  • ChrisChris Posts: 2,869Member
    edited April 2013
    Here's My Issue

    Your not looking for basic operational information. Your looking for the information the tradesman uses to put food on his table for his family. With that gained information you then think you can now just go purchase the boiler from the net. If you were a stand up guy, you'd purchase the boiler from the industry of those that helped you or support the local tradesman not a website that swipes your card.



    In my opinion you have been given basic operational information. Why should we feel obliged to give you more?
    Post edited by Chris on
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    · ·
  • smihailasmihaila Posts: 93Member
    edited April 2013
    Respect

    I agree, I'm asking for favours, true. I may be impatient and stressed out. It's just that I feel frustrated that questions that seemed plain English, simple, are not getting a direct answer (i.e. how vitotronic 200 is driving the system pump).

    I wasn't trying to 'steal' any secrets of the trade - I thought that for you guys, installing Viessmanns is a daily bread and the things which were unclear for me = to you were very simple things to answer. Look, I'll print all the docs  (as opposed to reading from screen) and read again all of them. Maybe I wasn't paying attention enough, and read it superficially. If that's the case, then my sincere apologies.



    Also, Chris was implying that I am trying to "short-circuit" trades men and their jobs...By going via Internet sellers etc. I mentioned about that only as a fall-back strategy. Because obviously it's less than ideal not to see the merchandise, to have to deal with forex conversion, brokerage/custom/duties and unforeseen situations. That is why, as a matter of fact, I am already buying the first batch of goods - the radiators - via a local company - which happens to be the main wholeseller for Canada.



    Now I am waiting for quotes for Viessmann and Lochinvar, pumps, copper piping etc. Also from a local warehouse - I consider myself fortunate enough (besides having the opportunity of getting professional opinions from you) to know a guy who has an account with two providers named Noble and Desco. Desco is the main Lochinvar distributor. I hope that I can get the stuff from them.



    For the manifolds, perhaps my father will just make them himself - or I'll try to convince him to buy them pre-fabricated. He's a quite an old fashioned guy. Did a lot of plumbing work in his life - mainly for peoples' house but also for some institutions such as schools or kindergardens. His father (my grandfather) was seen as the most crafty guy in his village. A jack of all trades - lots of people in the village were coming to him to fix lots of things: from cars, agricultural combines, to cuckoo clocks and doing even masonry :-)
    Post edited by smihaila on
    · ·
  • GordanGordan Posts: 873Member ✭✭
    I can understand all that

    Feeling frustrated is one thing, how you express it and at whom you direct it is another. Often (perhaps most often?) the simple English language answer to a direct English language question is "it depends." And often our frustration comes from a nagging feeling that we've gotten ourselves in over our head - something I'm personally very familiar with. But it was your choice to open up Pandora's box (instead of your checkbook) so you really should only be frustrated at yourself. :-) The kind people here don't owe you their time, so any amount of it that they do choose to devote to answering your questions merits appreciation. Even if you don't get a direct answer, you'll usually get some kind of a pointer where you need to do more learning, and that's invaluable! Also, their concerns about do-it-yourselfers (or their jack-of-all-trade relatives) have a solid basis in what they have seen out there (though, truth be told, some of the more horrifying examples paraded here appear to have been the handiwork of 'tradesmen.') When you come off as impatient, you're signaling that you're lazy in your quest for knowledge (whether this is true or not) and that rubs folks who have spent decades learning what you seem to want to (but can't) learn in days, the wrong way, and confirms some of the perhaps uncharitable preconceptions they may have about do-it-yourselfers in general.



    None of this is meant to discourage you from what you've set out to do, just to perhaps provide a point of view about how you currently seem to be going about it.
    · ·
  • smihailasmihaila Posts: 93Member
    edited April 2013
    Vitotronic 200 Service Instructions

    Burried inside the vast number of docs that are made available via the viessmann.ca web site, I have found a very interesting document, named Vitotronic_200_si.pdf. Which is applicable to Vitotronic 200 model KW2 (part number Z001 230). Also, very strange, the doc is not searcheable. I've spent some time last evening to ready it carefully. Considering the level of info that is there, I'm now beginning to understand why the shroud of "fuzzyness" and mystery from Viessmann. It seems to give some hints about certain algorithms and compensatory/adaptive types of controls.



    First of all, I'm not sure whether this is applicable to the Vitotronic 200 module that comes by default with WB2B models (i.e. called "HO1").



    Here's the the info that I consider paramount - perhaps you could help me in understanding a few things from the list below:



    -Page 18: "The heating curve can be adjusted along the desired room temperature axis, resulting in a change of the on/off switching behavior of the heating circuit pumps (HCP), if the heating circuit pump logic function is activated (factory default setting)."



    =>ok, when I saw the "pump logic function" being mentioned it stirred my interest. But further on I understood that it's more about warm weather shutdown stuff, freeze prevention and other auxiliary things. Read on.



    -Page 47: "Heating Circuit Control: The desired supply temperature value of each heating circuit is determined by the outdoor temperature, the desired room temperature, the operating mode and the heating curve."



    =>Note: "the desired room temp" does not necessary imply the presence of a room sensor/Vitotrol. But we'll see where that comes into the picture. Initially I got a bit disappointed when reading at page 76 about vitotrols, but then I realized something new. Read on.



    "The supply temperature of the heating circuit without mixing valve corresponds to the boiler water temperature. The heating circuit without mixing valve is dependent on the boiler water temperature and its control range limits. The heating circuit pump is the only control element.

    Room temperature: In conjunction with room temperature dependent control: Compared with the outdoor temperature, the room temperature has greater influence on the desired boiler water temperature. The magnitude of this influence can be changed via coding address "b2". (see page 94)."



    =>Now, we need to understand what the room temp means in this context. The "estimated" value or something delivered by an optional vitotrol?



    Pag 48: "Summer energy saving function (heating circuit pump logic):"



    => now we begin to understand what the HPL really means. It's not a general logic, but more in conjunction with warm weather or start of summer season.

    "If the outdoor temp is higher than the preset room temp setpoint value, the heating circuit  pump is switched off and the desired supply temp value is set to 32F / 0 Celsius. The switching threshold can be individually selected via coding address "A5" (see page 93)."



    Extended summer energy saving function: The heating circuit pump can be switched off:

    -if the outdoor temp exceeds a value preselected via coding address "A6".

    -if the desired room temp is reduced via coding address "A9". (see page 94) -- "Heating circuit pump logic function with change of setpoint / pump-off time"

    -in conjunction with heating circuit with mixing valve ([...])"



    =>This "A9" register seems to be very intriguing. Anyone caring to explain it a bit, and if it's available on the North-American WB2B models ? What is this "pump-off time"?



    Pag 50: "Variable frost threshold. Coding "A3" (see page 93). Values between 0 and 15 set various range for pump to be on and off."



    =>not super relevant to my quest :-)



    "Summer energy saving function (heating circuit pump logic function, outdoor temperature-dependent). Coding address "A5" (see page 93). Value=5 (default) means With heating circuit pump logic function (HPL). The heating circuit pump is switched off when the outdoor temp (OT) risese by more than 1.8F / 1 grd Celsius above the desired room temperature (RTdes).

    OT > RTdes + 1.8F (1grd celsius). Other values: 0=without heating circuit pump logic function (HPL function). Or other temp "edge" ranges via value=1...15"



    =>again, not super-exhilarating.



    Pag 51: Heating circuit pump logic function with change of setpoint. Coding address "A9" (see page 94). Value=0 (default) means without pump off time. Value=1...15 means WITH pump off time, which means Heating circuit pump logic function with change of setpoint (through change of operating mode or changes on "sun temp" selector knob or the "moon temp" button."



    =>tries to give more details, but still fuzzy.



    Page 76: "Vitotrol 200: The remote control has a built-in room temperature sensor for room temperature-dependent control in conjunction with a heating circuit WITH MIXING VALVE."



    Page 77: Vitotrol 300: same statement as for Vitotrol 200.

    =>When I've read that I was very disappointed. But you have to be very careful on how you read it. It tries to imply that a direct influence of the target/setpoint temp can be exercised only via a circuit with a mixing valve. And without mixing valve, there will be some "heurisitics" (and unclear if the room temp senzor is an input for these "heuristics")



    Page 82: "Components (continued): Input extension module 0-10V:

    To default an additional set boiler temp via a 0 to 10V input in the range 10 to 100 grd Celsius / 50 to 212 F or 30 to 120 grd celsius / 86 to 248 .

    To signal reduced mode and regulate a heating circuit pump to a lower speed.

    -Plug 144: 0 to 10V input

    -Plug 145: KM BUS to control unit

    -Plug 157: Zero volt contact



    See DIP switch marked as "B", with 4 switches. Can be set as follows:

    Dip switch 1 = on => reduced mode - Heating circuit A1.

    Dip switch 4 = on => set value default 10 to 100 grd celsius.

    Dip switch 4 = off => set value default 30 to 120 grd celsius.

    Note: out of switches 1 to 3, only ONE switch can be set to ON."



    =>Unclear what this "reduced mode" means. Also seems to imply that it works in conjunction to a var speed pump. Is such control available for American models?



    Page 92: Coding level 2, address "9d". Value = 0 (default) means without input extension module 0-10V. Value=1 means with input extension module (recognized automatically)"



    =>Seems to control what page 82 said.



    "A0:0 Boiler circuit/mixing valve circuit without remote control. Value=2 means with vitotrol 300 remote control."

    =>Not super-interesting.



    Page 93: "coding level 2, address "A3". Value=2 means The heating circuit pump is switched on at outdooor temps BELOW 34F/1grd celsius. The heating circuit pumps is switched off at outdoor temps ABOVE 37F/3 grd celsius."



    =>Seems related to warm weather shutdown regime. Not very "dynamic".

    "Coding level 2, address "A5". Value=5 (default) means With the heating circuit pump logic function (HPL function), the heating circuit pump is switched off when the outdoor temp (OT) rises 1 grd celsius above the desired room temp (RTdes). Other values = 1...15 will set different "edges" for the OT to RTdes relationship."



    =>Again, seems related to warm weather shutdown regime.



    "Coding level 2 address "A6". Value=36 (default) means Automatic switching from normal heating to summer operation NOT active. Other values = 5 to 35. Means automatic switching from normal heating to summer operations at a variable setting value from 41 to 97F (5 to 35 grd celsius) plus 1F/1grd celsius at which the burner and heating circuit pump are switched off and the mixing valve is closed."



    =>Again, summer time related.



    Page 94. Coding level 2 address "A9". Value=0 means Without pump off time. Value = 1..15 means with Pump off time: Heating circuit logic function with change of setpoint (through changing the operating moder or changes on the "sun temp" selector knob or the "moon temp" button."



    =>This is the most detailed info that can be revealed about the "A9" register. Again, I appreciate if someone could enlighen us more on this? Seems to be something essential.



    "Coding level 2 address "b0". Value=0 (default) means Weather-responsive operation in normal heating mode and reduced operation. Value=1 means "In conjunction with remote control: weather-responsive operation in normal heating mode and with room temperature depedent control for reduced operation". Value=2 means "In conjunction with remote control: room temperature dependent control for normal heating mode and weather-responsive operation for reduced operation". Value = 3 means "In conjunction with remote control: Room temperature dependent control for normal heating mode and for reduced operation".



    =>Not sure what weather-responsive operation means.



    "Coding level 2 address "b2". Value=8 means Room influence factor = 8 - in conjunction with remote control and operation with room influence coded for the heating circuit. Value=0 means "without room influence". Value =1..31 means "room influence factor adjustable from 1 to 31".



    =>Unsure if this involves the presence of a Vitotrol or it can work without it (some inference/Artificial intellifgence/Anticipative algorithms?)



    "Coding level 2 address "b3". Value=0 (default), means "Basic value: 127F / 53 grd celsius. In conjunction with the remote control and for the heating circ operation with room temperature control must be coded". Value = 1 means "Basic value: 100F / 38 grd celsius"."



    Page 95: Coding level 2 address "b5": Value = 0 means "no room temperature controlled heating circuit pump logic function. Value=1 means "In conjunction with remote control: Heating circuit pump OFF if actual room temp (RTact) is 5.4F / 3grd celsius higher than desired room temp (RTdes). And Heating circuit pump On if actual room temp (RTact) is 1.8 F / 1 grd celsius HIGHER than desired room temp (RTdes)"



    =>This seems interesting. Also the fact that Viessmann always seems to insist on using the "remote control" denomination for Vitotrols. Question: isn't there a typo? In both on/off cases, the RTact has to be higher than RTdes. Only the edge differs? Seems illogical.



    "Coding address "b6". Value=0 means without boost heating/rapid setback. Value=1 means in conunction with remote control: with boost heating/rapid setback."



    =>Boost/rapid setback: no idea what's supposed to mean. Something like a fast warming/cool down when you come home after a long time/vacation? Or party mode?



    Page 96: address "b7": in conjunction with remote control in room sensing mode: without optimized switch-on time or with optimized switch-on time.

    b9: Without or with learning optimized switch-on time.

    C0: idem to b9, but in conjunction to remote control.

    C1: values for C0 for the time shift.

    C2: with/without learning optimized switch-off time.



    C8: Without limit on room influence (value = 31) or 1...30 means "in conjunction with remote control: limit on room influence variable from 1.8 to 54F / 1 to 30 grd celsius."



    =>C8 seems to state, for the 1st time, that the Vitotrol seems to have a certain influence in the indoor temp estimates and that Vitotronic 200 will consider within its internal algos that input. In what manner - it's mysterious.

    =>Also, what "switch-off time" may mean?



    d5: interesting.



    "E5: With or withour variable speed heating circuit pump. Value=1 (non-default) means "with" (recognized automatically)

    E6: max speed of variable speed pump.

    E7: min speed of variable speed pump

    E8 and E9: again speed control for var speed pump."



    =>The E5,6,7,8 and 9 registers seem to be dedicated to controlling a var speed pump. Is such pump available in North-America? And where do you plug it in?



    Page 100: "the heating circ pumps are switched off before the desired room temp is reached. OR, the heaitng circ pump for heating circ 1 or heating circ 2 is switched off if the current room temp exceeds the desired room temp by 5.4F / 3grd celsius. The default settings is "the heating circ pumps are switched off in the heating program if the outdoor temp rises more than 1.8F/1 grd celsius above the desired room temp."



    =>This page/paragraph tries to summarize what those options are really meant to control. Looks interesting.



    And finally, a 2nd document about Vitotronic, titled "Vitotronic_200_TDM.pdf" says on Page 5: The installed sensor measures room temperature and, if necessary, takes corrective action and initiates fast heat-up at the outset of the heating operation (if coded).



    Sounds interesting overall. The viessmann seems to be a little hidden gem, somehow (I personally feel) shrouded in some (intentional maybe) mystery as far as the control and internal logic are concerned.



    I've also received the quotes for both WB2B-19 and WHN055, and the prices are pretty much the same. But for the Viessmann, you have to pay additionally for LLH, LLH immersion sensor, 2 Grundfos Alpha pumps (one set to fixed regime for the primary circuit and the other to variable Delta-P for secondary), plus concentric venting kit, plus vitotrol 300. For the pumps, let's say it's not a concern - because as opposed to WHN055's integrated pump (a UP15-55) I can install something more energy efficient/ECM.

    If it were for WHN055, I'm not sure if an indoor control/sensor exists similar to vitotrol? I guess it counts only on a "on/off", classic thermostat (i.e can reuse what I have from the forced air furnace?).



    My biggest concerns right now are:

    1. That even with a LLH, Viessmann's high min. BTU load start limit (30kBTU) may be too high for my load? But where is that 5:1 "down modulation factor"? Shouldn't it be 67k divided by 5?



    2. Lochinvar's warranty seems VERY FISHY to me. Looks like they have something to hide. Stuff like: "no warranty for parts which the boiler aggregates but not manufactured directly by Lochinvar", also "warranty starts from the manufacturing date indicated on the boiler unit, and not from purchase/install date" and that stuff also with pro-rated warranty. THIS SEEMS EXTREMELY FISHY.



    Thank you and sorry for the long message.
    Post edited by smihaila on
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    edited April 2013
    Smihaila

    Why are you still considering the Vitodens?  The specific model you are looking at can only modulate from 31 to 67 MBH.  I thought your house required only a maximum of 30 to 35?  Almost all of the features of concern are contingent on the boiler functioning in its modulation range. 
    Post edited by Eastman on
    · ·
  • smihailasmihaila Posts: 93Member
    Was still considering it

    simply because I am worried about the quality and reliability of the other alternative. It's true that somewhere, at its origins, the Lochinvar's design was inspired by some European model (Giannoni) and started building up/improving from there.

    If many people are using Lochinvar wall hung models and haven't encountered major issues with them, I could go with it. Still, I was puzzled by the fact that the 5:1 modulation/conversion factor with the Vitodens somehow doesn't add up.

    Eastman, would you say that the Knight is a damn good boiler? If you don't pipe a P/S with it, would it still be possible to use a variable speed pump, as long as you can guarantee that there will be 2-3 rads fully opened, permanently, to have a min flow assured? Lochinvar was stating that for a var speed design only a P/S circuit is recommended. I wished to have min electrical energy consumed - and even if those 0...10 VDC controlled pumps from Grundfos or Taco (VFD?) are not ECM, by being variable I suppose they will draw considerably less than a UP15-55 which is const speed? Or Alpha could be used, in delta-P, but without an interface/a way to tell the boiler what flow the pump is currently using.

    Thank you.
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    Giannoni

    Many mod/cons used the Giannoni HX to get a product on the the North American market quickly while other designs were being developed.  There is now quite a variety.  The WHN055 uses a fairly unusual vertically oriented firetube hx that has received positive reviews.  The Giannoni hxs are watertube.  There are pros and cons with each style and many manufacturers offer product lines featuring more than one type of hx.



    Where are you reading the 5 to 1 modulation for the Vitodens?  This ratio is most likely for two units sequenced together.  Don't they make a smaller model?  What other manufactures do you have access to locally?  Even the best engineered systems fail; having quick access to replacement parts and trained service reps should be considered.



    How much do you pay for electricity?
    · ·
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