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Pumping Awa Question

tom3holer
tom3holer Member Posts: 45
Just read Pumping away and as a hydronic novice learned a good deal and thoroughly enjoyed it.

As I have posted on another thread here I have a new installation wrought with issues.

The plumber that installed the WAY oversized boiler also plumbed the the zone pumps in the return line. In Dans book he describes why this is bad practice. He also makes it very clear that in a system plumbed P/S you must always pump away from the supply tee and toward the zones. This is not the way he plumbed it. I have included some pictures. Will this effect the operation of the  P/S interface?  Do I need him to come back over and correct it?

I have included some pictures that twill hopefully help.



Tom
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Comments

  • heatpro02920
    heatpro02920 Member Posts: 991
    Heres the thing?

    We all install things differently, that being said I have seen thousands of systems with circs on the return side {some guys swear by the practice, because it allows the circulators to operate under cooler conditions} and them systems have worked for a long time... What I am trying to say is sometimes there are 3 ways to get something to work, the rite way, the wrong way and the way you wouldn't have done it, but all 3 ways can work....



    Now I have had customers call me after an install and tell me I didn't do it rite because "their cousin is a plumber" or they "read on the internet" or they "seen at their friends house" and I can tell you first hand its not a good feeling. It doesn't happen often but through out the years it has happened... I just had a women call me because when she ran out of oil {on a boiler I installed 4 years ago} and had to get her boiler primed the oil truck driver that primed it said that I should have installed a filter at the burner {which is non sense}, but it still got me a call that I had to deal with, I explained that I like to filter the oil before the oil line as close to the tank as possible and the way I did the install was to the best of my experience and education... It was good enough for her, but its a pain in the ****... And the other thing is I was not going over to change it unless she wanted to pay me to do so...



    Anyway now onto your system, can we have some more info and pictures? What kind of system is it{forced hot water, radiant, ect?}, what boiler, ect?



    Pics of the boiler and piping would help a lot...



    As far as PS piping, I just stated in another post about this, everyone has their own method.... If it is going to create a lot of extra fittings, I wont space my 90's out of the closely spaced tees and the systems always work and work good, I have done it both by the book and by the job and both work the same... Now on the other hand I have also seen it piped wrong and not work... sooooo... which is yours?
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Does it work?

    As Heatpro so accurately said, there are many ways to do almost anything, and arranging circulator pumps is no exception.



    The first question is -- does it work the way it is set up now?  If the answer to that is "yes", then be happy and leave it alone.



    The big and important question on any pumping scheme -- and it doesn't matter whether it's a little circulator somewhere, or a couple of thousand gpm on a water supply, is is there enough pressure at the inlet of the pump when the pump is running to prevent problems.  The reason for pumping away from the point of no pressure change is that it is much easier to guarantee that this is the case.  On the other hand, the point that the water is hotter there is also valid, and more pressure is needed when the water is hotter than when it is cooler.  This aspect of pump selection and sizing can be a little complicated -- but, as I note...



    If it ain't broke, don't fix it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    Piping

    The piping shown has errors. The return header should be larger than the zones attached; 5 zones of 3/4" should return into a min. of an 11/4" return. I would have used 5 zone valves and 1 variable speed pump. It would have saved 400w of electricity and the cost of 5 pumps. If the pump(s) are installed pushing towards the expansion tank and CW feed inlet, the system will have entrained air.

    Every heating technician has their opinion on "how to do it". Proper piping practices have been known for over 20 years now and variable speed pumps for 7 years. Not that many techs follow the "near-boiler" piping rules nor use state-of-the-art equipment. The reason is cost and training and education opportunities that are ignored. Homeowners also put pressure on the contractors for wanting the lowest pricing and choose price over experience. Those systems are often compromised and under-performing.
  • heatpro02920
    heatpro02920 Member Posts: 991
    I wan't to see more pics

    Paul I see more and more guys using zone valves over circulators, but I just can not bring myself to make the jump, sure I use a lot of zone valves in my jobs, but on the mid to high end jobs I almost always use circulators, either alphas, bumble bees or delta t's, ect... I know a lot of guys mention the power usage but for the amount all the zones are calling at once and the power zone valves use, I cant imagine the power savings are very much.... I like a bumble bee on every zone....



    OP, now you see how most pros are going to do things different, it happens every job, sometimes my guys will finish a job and Ill walk in and say I wouldn't have done that, that way, is it worth changing {hardly ever} will it work, yep, just not the way I would have done it....
  • SWEI
    SWEI Member Posts: 7,356
    Zone valves and ORC

    Conventional zone valves and bang-bang thermostats are not a good match for outdoor reset, except when used as high limit controllers.  They are incapable of delivering the fine-grained control of individual space temperatures which occupants expect due to the small delta between fluid temp and space temp.



    On commercial jobs, we use Belimo CCVs with 2-10V inputs and DDC, which gives us proportional control that works nicely with ORC.  I'm still working on a residential package we can afford to support.
  • heatpro02920
    heatpro02920 Member Posts: 991
    I like how you talk

    sounds smott... lol, If you are ever in CT, RI, MA area I'm giving you a job, Swei, lol
  • SWEI
    SWEI Member Posts: 7,356
    proportional control

    is really the cat's meow for both comfort and efficiency.  TRVs do a bang-up job for the average homeowner -- far better temperature regulation than most have ever experienced.  I'm just trying to replicate that for a wall-mounted stat, which has a better location for both sensing temperature and occupant use.



    I'm somewhat surprised at the lack of off-the-shelf proportional output tstats. Did I miss something, or are they somewhat rarer than hen's teeth?



    Just starting to build momentum down here in NM, though I certainly appreciate the offer :)
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    I'm somewhat surprised at the lack of off-the-shelf proportional output tstats.

    I had one once on a serious air conditioner for a large ($4000/month) computer. It took in running water for a humidifier, a drain for humidifier overflow (on purpose to prevent deposit build-up on the 3 cal-rod heaters), 240 volt electrical power for the blower and the heaters for reheat. And about a 1 1/2 inch pipe in and out for constantly flowing chilled water.



    The thermostat was a finger that rode on a potentiometer, and the output of the potentiometer drove a motorized valve that at one extreme ran all the chilled water through the enormous finned tube heat exchanger, and at the other extreme, bypassed the heat exchanger completely. There was about a + | - 1F proportional zone around the set point, and it ran bang-bang if it got out of control, which is very seldom did. I was amazed they even made such a thing, but the building engineer had no trouble getting the stuff.



    I suppose it was one of these:



    https://shopping.aol.com/honeywell-t921a1191-135-ohm-proportional-thermostat-56-f-to-84-f/pg747235847
  • Eastman
    Eastman Member Posts: 927
    What is...

    an ORC?
  • SWEI
    SWEI Member Posts: 7,356
    ORC

    = Outdoor Reset Control
  • SWEI
    SWEI Member Posts: 7,356
    proportional controls

    have been around forever.   Mechanical, pneumatic, analog electronic, and more.



    Just seems a shame to be controlling all these newfangled modulating furnaces and boilers with on/off thermostats.  Look at all the intelligence and innovation we're seeing in networked tstats -- that communicate with the system over a one-bit, one-quarter baud channel.
  • Eastman
    Eastman Member Posts: 927
    What I don't understand is...

    why are thermostats still so stupid.  It seems like it's time to move beyond just closing a contact.  Are you familiar with the OpenTherm communications protocol?  Something like that may eventually evolve into the cheapest way to implement proportional control. 
  • bob_46
    bob_46 Member Posts: 813
    Proportional

    What I have always dreamed about is an inexpensive proportional control for residential

    applications that modulates the temperature of the water in each zone and not the flow rate .
    bob
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    Making smart thermostats

    Lets get all the parts to communicate wirelessly, or through the power lines while we are making them smarter.--NBC
  • heatpro02920
    heatpro02920 Member Posts: 991
    T-stat technology

    is just starting to come around, I would like to see something with a central panel and wireless sensors for each zone, internet connectivity for smart phone control, wireless hello/goodby switches {being able to push a button on your way out the door and having your t-stat drop back to a lower temp and then when you are on your way back pushing a button on your cell phone to turn it back on so its warm by the time you get home}, also a smart control that managed boiler run times would be nice -comfort may suffer a bit, but having a control that will manage your run times with some degree of "thinking" would be nice, so if all zones are set to 70* and one falls down to 69.0, and another is 69.6 with the rest 70* it will wait until all fall down before it kicks the boiler on {to a maximum setpoint, say 1.9*}, then once the boiler is on it will heat all zones to 70.9 even if they were already at 70.0 when the first cold zone called...



    I read an article a while back, that showed a "smart" hydronic system, every room was on its own zone with 3 way zone valves all over the place, the system would divert warm return water to other rooms, run the system forwards and backwards, send exactly the needed temp and quantity of water to each zone as it was needed, all running off of 2 mod/cons {they were different sizes} and it showed one {the smaller of the two} could mod down to 6K BTU's {which matched the smallest zones heat loss on an average winter day instead of our design day}. But what interested me was the smaller boiler had a heatpump feature to satisfy the low heat needs... This was a drawn out system, nothing in production, and I believe it was Burnhams ideas...
  • Gordan
    Gordan Member Posts: 891
    There are both pros and cons with that approach

    The pros are pretty obvious... modulating flow doesn't work too great with zones that are plumbed as a series circuit, as you're really not reducing output in the lead emitters at all, and are reducing it too much in the downstream emitters. Modulating temperature would be more versatile as it would work with any layout.



    The cons are that modulating temperature requires, once again, that each zone be separately pumped.



    Beyond that, there's no technology that proportionally modulates flow, that can't be turned into proportional modulation of temperature - you just apply flow modulation to injection flow rather than circuit flow, et voila! With these newfangled multi-circuit boilers that allow you to program in multiple reset curves, you just connect your mixing control boiler enable to zone heat demand on the boiler, program in the correct curve, and let it fly... the highest temp demand will win the boiler supply temp battle, and the rest will get hashed out by mixing. Now cheap... the cheapest way I'm aware of would still be in the ballpark of a grand per zone for control/circulation alone. Comparison to a TRV is not favorable.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Boiler Manufacturers

    Need to take the next step with boiler controls. Thermostats should communicate with the boiler. Shold be one inculsive system. Eastman spoke about Open Therm. Viessmann uses it and on the next version Vitodens 200 coming this season will bring Vitocom which has been in use for a few years across the pond. There's an IPhone, IPad, Android app for it. Gives the consumer access to scheduling, turning the boiler on or off, dhw, and current status.



    Taco IWorx will give you the same and it's not crazy expensive though you are taking away the boilers control making the IWorx the new brain. Have done a couple of job with it. Works great, no problems.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    All this stuff

    is available, when one goes looking.  Some of it would take a good deal of custom installation at the moment, but it's there.



    The bigger problem is the software to control it all.  This is not so simple; I had the [mis]fortune to be involved in some controls engineering at one point -- just about enough to have a pretty good idea that I had only a very poor idea as to what I was doing.  The goals are clear enough -- minimize energy use while maintaining desired temperatures in the various spaces.  Getting from there to the actual control algorithms is by no means simple -- and worse, would have to be custom programmed for every single installation and user.



    I expect it's coming, though, in situations where the cost is regarded as worth the effort.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • unclejohn
    unclejohn Member Posts: 1,833
    proportional prosmorshunional

    I use those evil on off tstats and they stay within a 2* diff. Thats fine for me. Also when it's broke it dosent take hours and hours to trouble shoot and cost a thigh and a shoulder to fix. I have found even the most simple energy saving devices don't save enough over their lives to pay for the replacement costs. 
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    I had only a very poor idea as to what I was doing.

    Long ago, I knew about this kind of thing. I was working for a small electronics company and we did things like building control systems that would land an airplane. That is much more difficult than designing an autopilot. We also built other things that worked on similar principles, mostly classified. But I have not done anything like that since about 1965, and what I used to know is mostly forgotten, and some of it is obsolete now. But to really understand even a sophisticated thermostat system requires a knowledge of control systems. I am glad I do not have to know this stuff now because I would have to learn it all over again. I know just enough to see why I should not even try to use setbacks on my radiant slab heating zone because it is hopeless. It would overshoot because the delay in response is so much that if the gain in the feedback loop is high enough to hold the desired temperature, then the system is unstable.



    https://en.wikipedia.org/wiki/Control_theory
  • tom3holer
    tom3holer Member Posts: 45
    edited April 2013
    More pictures

    Here are some more pictures of my system.

    The home is a 1860 built Sea Captains house on Cape Cod. It is 2300 Sq/Ft with upgraded windows and insulation. The boiler currently installed is an Alpine 150. I did the heatloss on the  on the house  by both the fuel used method and the Slant/fin calc and came out just slightly below 60k. After I did my homework and realized the plumber had not done his for this installation  I told him I wanted it removed and the proper size put in. He did agree and is replacing it with an Alpine 80. Hopefully early next week. Most of the piping will remain as it is which I am still concerned with.

    Here are some more pics I took today. I understand why the pumps are in the return lines but the way I see it, its not pumping way. I am hoping this can be changed fairly easily as I am starting to hear water running in the upstairs zone, air in the zone.

    The return manafold is the same size, 1", as the P/S plumbing. The flow through the P/S piping is ,return going left to right on the lower loop and mixed going right to left on the upper loop. The zone pumps pump into the return manafold then go through the P/S loop and then down to the air seperator and the compression tank. This is my concern as Dan says in his book "MAKE SURE YOUR SECONDARY PUMPS  ALWAYS  "PUMP AWAY"  FROM THE SUPPLY TEE TO THEIR ZONES." This does not seem to be plumbed that way.

     Hope that makes sense.



    Thanks again for any suggestions,



    Tom
  • heatpro02920
    heatpro02920 Member Posts: 991
    Hmmm, swapping an alp150 for an alp080?

    That boiler is over $1100 less boiler.. you are obviously not happy with the boiler install and its good they are willing to return and make it rite, but chances are you are going to end up with less than you have rite now... I think I would keep the oversized boiler unless I was getting the price difference back.... But on the other had I would rather have aboiler that mods down to 16K vs 30K depending on the zone sizes and styles {a hydro air sucks the heat out of your loops fast but a radiant circuit is slower}...



    If they are willing to repipe, have them use bumble bee circs and an alpha 15-55 on the primary, I like to pull the DHW circ and return off of the primary loop before the closely spaced tees, and change then have them locate the vent where you want it and what ever else you found wrong, then maybe it would be worth the swap to the smaller unit...

    Alpines are decent units, I always installed the gb's over them and now the TT solos, but its a well made good looking unit...
  • heatpro02920
    heatpro02920 Member Posts: 991
    Hmmm, swapping an alp150 for an alp080?

    That boiler is over $1100 less boiler.. you are obviously not happy with the boiler install and its good they are willing to return and make it rite, but chances are you are going to end up with less than you have rite now... I think I would keep the oversized boiler unless I was getting the price difference back.... But on the other had I would rather have aboiler that mods down to 16K vs 30K depending on the zone sizes and styles {a hydro air sucks the heat out of your loops fast but a radiant circuit is slower}...



    If they are willing to repipe, have them use bumble bee circs and an alpha 15-55 on the primary, I like to pull the DHW circ and return off of the primary loop before the closely spaced tees, and change then have them locate the vent where you want it and what ever else you found wrong, then maybe it would be worth the swap to the smaller unit...

    Alpines are decent units, I always installed the gb's over them and now the TT solos, but its a well made good looking unit...
  • Eastman
    Eastman Member Posts: 927
    Why the alpha on the primary?

    Rather than another bumblebee?
  • CMadatMe
    CMadatMe Member Posts: 3,086
    If They Will Re-Pipe

    I'd get rid of all those zone pumps in favor of Taco Zone Sentry Zone Valves and use a Bumble Bee as my system pump. I'd also favor a low loss header instead of the pri/sec piping.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • heatpro02920
    heatpro02920 Member Posts: 991
    edited April 2013
    nah.

    I don't think a bumble bee will do it even on locked high, if I remember correctly they want a 0015 on that units primary side.. I would think an alpha on high would get the job done, plus I dont run delta t on primary side, that will not work rite {ask me how I know, lol}... Pressure variable like the alpha will work, and the alpha is now my go to primary size pump when it fits and I think the 15-55 will just do it for the 080... You will have to check a chart or two to figure this out... You don't want to slow down the flow on your primary side, this will create problems, you will short cycle, overheat, ect... Keep that flow going around and let the zones take what they need out of the supply side returning as much cold return water as they can...



    as for zone valves and delta t circs, I never seen this benefit {again ask me how I know}, the delta t circ will change the flow for all 5 zones depending on the return temp and some return temps are going to be warmer than others ,this will also create havok for an indirect... I also don't like zone valves {for a lot of reasons} IMO, the best way to zone is check valves and separate circulators, this allows you to control the zones delta individually, plus if your circ dies, you don't lose heat in the entire house...



    And as far as a low loss header, I don't think the alpine ever came with one {buderus did} but adding a hydro separator is always nice, but the cost is a big factor to what real worked benefits it has over closely spaced tees... I have done plenty systems with them, I used the tacos on smaller jobs, and I have seen them in the field {normally larger systems}. And I don't see a difference, the only things they offer are air separation and sediment control.. a handful of tees will do the same thing for a lot less money... now if they make a nice cheap one for $65 {1" and 1 1/4"} that would be worth it... Spirovent has one but its not readily avalable as for as I know...
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited April 2013
    The Benefit

    Let's see. The zone sentry's will use less electricity, 3yr warranty, ball valve style with a very high CV rating.



    The bumble bee will do the job. The Alpine 080 sizing your boiler pump via the 30 degree rise. Need to move 4.9gpm @ 6.4' head.



    http://www.taco-hvac.com/uploads/FileLibrary/102-435.pdf



    The Bumble Bee out performs the Alpha hands down. Beta tested Bee's for 3 years with Alphas right next to them.



    Subtract the cost of the spirovent and the LLH is not that much more. No different then the cost between a 007 and a Bumble Bee. The big benefit, protects the HX.



    How would the Bumble Bee creat havoc with the Indirect? Have tons of jobs running exactly this way. Keeling my delta-t consistent across the coil assures I'm seeing proper flow and btu/hr extraction to the coil.



    Saying that you need all circs on zones is like saying you don't use actuators on radiant manifolds but substitute circulators instead. Do you use circuit setters on all your zones to assure proper flow or do you just let the pump operate on it's curve?



    Attached are the Alpine Flow Rates and the Curve for the Bumble Bee
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • heatpro02920
    heatpro02920 Member Posts: 991
    edited April 2013
    Chris

    I also use bees on indirects alone, but having the indirect on a zone valve and a few zones calling {with out priority} causes call backs... I find that if you use delta t on an indirect it works great, by itself with a fixed supply temperature... As soon as you start changing the supply temps and flow rates you get problems.... But changing just the flow rates works very well.... I wouldn't want other zones pulling away from it.. DHW priority could work, but I as a rule don't like to put zone valves on indirects, although as I said, priority can cure most of the issues... but this is coming from me, I also don't like using winter heating systems to supply DHW, and a lot of people disagree with that too...



    As far as the bumble bee vs the alpha {like I said I don't like delta t on primary loops, I have tried it, its not rite...} and the bee is 15 gpm max and 15 ft head max, the alpha is 22 gpm and 20 ft of head..... Its a stronger pump hands down, I also have used both, I have 3 bees and an alpha on my solo175 at my own home...



    Which LLH do you use? link? the cost difference is the big factor for most installs, a few tees, a vent, and a wye strainer cost under $75, even the cheaper taco hydro-separator {and its nothing special has a hi vent on top and steel wool in the bottom with 3 connections lol} is $400!!!! The spiro model I priced for a job about a month ago was around $600!!! That's just not worth the benefit.... even the bee vs 007 {the 007 pumps over 20gpm bee only pumps 15} the price is double, and since taco is only making 40 a day they are tough to find {I have a half dozen in stock but one job could wipe them out}...



    Now as far as the circs vs Zone valve debate, its just how I feel, the electrical consumption is BS to me, because although it may indeed use less, its not as much as people say...



    If you have 1 circ for 3 zones that circ is going to run longer than any 1 circ if you had 3 separates... Plus the zone valves use energy {albeit not a lot, but some}, so when you start taking these things into consideration the energy difference is not 300%.... Plus the new circs don't use much energy, but when I put a bee on 3 zones and all 3 start calling the watts almost triple anyway, so whats the difference, nothing...



    I have installed thousands of heating systems, and I can tell you zone valves have there place, but in a higher-end baseboard, indirect, hydrocoil system is not one of them {as far as I am concerned, as I said everyone does everything different, doesn't mean its wrong, just not the same}...

    Just the fact that if that one circ quits the entire building is with out heat is worth the extra cost for me personally, to know that one circulator isn't the difference between me having heat and not....



    And its been a while since I did an alpine but I remember them calling for a 0015, not really interested enough to look it up, but I specifically remember 0015 on primaries...



    As for radiant mani's and actuators{zone valves} I have done systems that get a 00r for each radiant zone, not all systems use zone valves, I have a lot of systems with the roth shunt setup too... I tend to do radiant one of two ways, I either run a tankless water heater {or mod/con} with a circ on each zone and a 3 way zone valve on the return for diversion incase the delta closes up, or I run the radiant as its own system with a plate exchanger then I will use a single circ with zone valves for each manifold... I think thats what you were referring to and I hope I said that rite...



    Now as far as circuit setters, I only use them when they are needed, again, COST, they are around a $100 each, so no I will not set them in every install just to set the correct flow, Ill pick the closest circulator to get the job done...



    I'm not arguing that zone valves are a terrible idea, just that I would rather have 3 circs vs 1 circ and 3 zone valves.... I have been using the new style tacos zv's for a while now {taco is rite down the road here we tend to get new stuff on the shelves before the rest of the world, I own a 3 family rental property 125 feet from Tacos front door!!!} and they are nice, a lot nicer than the golds, but now the circs got a lot nicer too so its kind of a wash, bb vs zone valve I'm going circs everytime....



    Edit - I just looked at the flow charts you linked, the 080 wants 7.3 gpm and 14.7 ft head for 25* delta, the bee barely pumps at 14.7.... and it says recommended pump is a 0015 which is a remember correctly almost mimics an alpha 15-55 {highs}, no were near the bees highs, the bee has a straight 15-15 curve... I have to disagree with you, I don't think a bee would be the rite choice, actually even though the alpha is much closer its still less powerful than a 0015 throughout the curve....

    heres a revised supplement shows a 0010, which sounds like overkill, I think they are talking about on a loaded loop not primary...

    http://lib.store.yahoo.net/lib/yhst-13738724167386/Alpine-Recommended-Circulator-Models-Supplement.pdf



    but they show a chart with the loss and flow, it shows that when you get around 7 gpm through the heat exchanger you will be around 10 ft of head, and if you check you BB chart, thats not going to happen but the alpha will get you there....
  • tom3holer
    tom3holer Member Posts: 45
    edited April 2013
    Looking at the charts

    In looking at the manual I appears tha the 80 requires 5.8gpm with a head loss of  10.3, so the BB would a wee too small. Now this is what I am still having a problem understanding. I have read many times that zones should be sized for a 20* D/t and on a mod/con P/S setup you want to have a high D/t on the primary for efficiency. The Alpine manual shows a flow rate at 35* of 4.2gpm with a total head loss of less than 6 which is well within the BB range. I just don't understand as a practical manor how one can get 25-35* D/t's on the primary circuit. If the boiler is putting out 160* water part of it is circulating through the boiler and part of it is 140* zone return water. Assuming all the zones are running and returning 140* water and the boiler is putting out 160* where does the 25-35* D/t's come from?



    Tom
  • CMadatMe
    CMadatMe Member Posts: 3,086
    As a Fellow Rhode Islander

    Though I moved to NY 8yrs ago have been playing with the Zone Sentry and the Bee for quite a while now. Have plenty in stock.



    Why does everyone migrate to the 20/25 Rise on condensing boilers? I want my boiler flow to be a minimal as I can. This way I can scrub out all the btu/hr out to the system side. Using the Alpine 80 as an example on that 25 Rise where does the rest of that flow go thst your not pulling out because only 1 zone is calling. Right back to the boiler and it keeps your return temps high.



    I sell Taco LLH and the HSEP-1000 is less then 3 Benji Franks..Most use Viessmann's which is closer to 2 Benji's and that comes with an insulation kit.



    I agree no wrong or right way with Valves or circs. Do not necessarily agree with you on you have to zone with circs with hydro. 99% of air handlers are oversized and pressure drops are pretty minimal. Heck I have systems out there seeing 115-120 degrees through A/H with no problems what so ever.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited April 2013
    You Don't Have To Tom

    The boiler side and the secondary of system side are two complete different systems in a sense. Temp Rise on the boiler side refers to the minimum flow needed to get the full out put of the boiler.



    4.2 x 35 x 500 = 73,500 Btu/hr

    4.9 x 30 x 500 = 73,500 Btu/hr

    5.8 x 25 x 500 = 72,500 Btu/hr

    7.3 x 20 x 500 = 73,000 Btu/hr



    All the boiler side is doing is making btu/hr out to the secondary side. How you take it on the secondary side in moving it, drinking it, eating it is up to you.



    The only time you will get the full boiler rise is when you need all the btu/hr out of the boiler. What never changes it the gpm the pump choice gives. You will always move that flow.



    The reason I like to use the higher rises is that I have a better shot at moving the boiler flow rate out to the system instead of sending some or most of it back into the boiler which keeps my rise or delta-t higher. Zones are not generally running at the same exact time so If I can scrub out the gpm into the secondary or system side then I'm getting the but/hr created in the boiler out.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Eastman
    Eastman Member Posts: 927
    edited April 2013
    I'd like to point out that...

    the boiler chart info for the Alp80 @ 25 degrees is incorrect.  There is a footnote  ---it basically says:  This number is not for 25 degrees.  (As stupid as that sounds, that is what it says.)



    @Tom: Where did you see a headless of 10.3 associated with 5.8 gpm?  Did you estimate that?  (This isn't a ced style rant, just wondering if you have a different manual than the one I'm looking at.)
  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited April 2013
    This Is the Most Current

    I didn't see any side note. My manual is dated 2/13
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Eastman
    Eastman Member Posts: 927
    edited April 2013
    In that first table...

    for the Alp80,  see where it says 7.3 (1) for the flow rate at 25 degrees delta?  The footnote says:  the data for the Alp80 at 25 degrees is actually for a target flow at 20!  Hilarious.



    "(1) Temperature Differential = 20°F"



    The one I'm looking at is dated 2/13 too.  I think when u clipped it the bottom row got missed, that's where the footnotes are for that chart.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Precisely Why

    I never use the recommended pump charts. Rather use the actually pressure drop across the HX. Don't know many 50 equiv feet of piping on systems for the pri side out there either. Guess that's why I missed it. Never really read that chart because it has more fudge in it then fudge brownies. Not just Burnham either, all of them..
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Eastman
    Eastman Member Posts: 927
    @Tom

    "I just don't understand as a practical manor how one can get 25-35*

    D/t's on the primary circuit. If the boiler is putting out 160* water

    part of it is circulating through the boiler and part of it is 140* zone

    return water. Assuming all the zones are running and returning 140*

    water and the boiler is putting out 160* where does the 25-35* D/t's

    come from?"



    It can't come from anywhere because the assumptions are physically impossible.



    Here is why:



    Although a primary/secondary allows two systems with a variety of flows and temperatures to be connected, for the purposes of analysis, one can benefit by grouping these hydraulic states based on the following criteria:



    a) flow in the primary = secondary

    b) flow in the primary is less than the secondary

    c) flow in the primary is more than the secondary



    Let's take a look at condition 'a' first.  This doesn't happen often in practice, but it can be done.  For example, let's say you have a delta T circ at 30 degrees on the primary and all the other secondary pumps are also set to 30 degrees.  At an achievable steady-state, (this would require a suitable ODR curve and btu load)  the flow in the primary is equal to the secondary.  When this happens boiler output temp is equal to secondary system supply input temp.  And boiler return temp is equal to the secondary system return temp.  The water will not mix.



    Suppose you adjust the secondaries down to 15 degrees.  At an achievable steady-state this requires twice the flow rate as before.  If the primary is still at 30 degrees, the boiler flow is only half of what is moving in the secondary.  This is condition 'b'.  At these flows, the return flow from the secondary exceeds that which is being drawn in by the boiler return.  Hence the boiler return temp must equal the secondary return temp.  Extra return water gets diverted to the supply where it mixes with the boiler output and reduces it's temperature before being sent back out to the zones.



    Let's take a look at your question again now.  If all the zones are calling and you're using a suitable ODR setpoint curve, one can assume the system is reasonably close to a steady-state.  If you are running a 30 degree delta on the primary and 20 degree deltas on the secondaries, then we are running at condition 'b'  -- flow in the primary is less than the secondary.  If you assume the the secondaries are returning 140 degree water, then logically the boiler is receiving 140 degree water.  Hence the boiler must be outputting 170 degree water.  This 170 is being mixed down to 160 before being sent out to the zones.  We can infer from this information that the boiler setpoint must be 170, even though the fintube system only requires 160.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Exactly

    There is always a mix action unless the system side flow rate and the boiler side flow rate are exact at all times. Unfortunately with a fixed speed boiler pump it will only happen once. When all zones call at the exact same time. The majority of the time when running on the pumps specified in the charts you end up with low boiler rise (low fire) because you cannot exhaust the btu/hr being made on the boiler side out to the system side.



    It is a def flaw in boiler control and logic design if you asked me. Boiler pumps should be controlled by the boilers control via variable speed. Move what is needed and no more. The minimum flow rates in the charts are deceptive. Those are the flows needed to get all the btu/hr out of the boiler at high fire. Minimum flow rate really should be what the minimum flow is for low fire but we don't use variable speed pumps like they do across the pond.



    The Alpine 80 min is 16,000 Btu/hr output why should I need to move anything more then 1.6gpm across the HX at low fire? The boiler only holds 1/2 gallon of water.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • SWEI
    SWEI Member Posts: 7,356
    boiler pumps

    "Boiler pumps should be controlled by the boilers control via variable speed."



    Amen to that.



    ∆T control is great, but it makes so much more sense for the onboard controls to manage the pump directly.  I really don't understand why this is the exception and not the norm...
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Cost and Installers

    It would drive up the price and let's be honest about who is actually installing these days out in the field. While there are great guys out there they are not the majority.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • SWEI
    SWEI Member Posts: 7,356
    If I were designing the onboard controls

    I would include not only a 0-10V output (a la Lochinvar), but also a TRIAC output (similar to Heat-Timer, Caleffi, etc.) to directly drive a wet-rotor circ.  This would allow the use of off-the shelf pumps with minimal installer training.
This discussion has been closed.