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Modcon Heating Cycles Per Hour

ced48
ced48 Member Posts: 469
I am averaging about one heating cycle per hour with my newly installed Lochinvar 55 with fin tube baseboard. I am running water at 120 -135 degrees, depending on outside temperature. The cycle has the boiler running from 20 to 35 minutes of the cycle, again depending on outside temperature. Am I at a good point, or should I be trying for more run time, with even cooler water?
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Comments

  • SWEI
    SWEI Member Posts: 7,356
    Is the thermostat sutting off the boiler?

    or is the boiler shutting off on limit?



    How close are you to design temp when this is happening?  I generally crank all thermostats to at least 80ºF, then tune the ODR curve over the course of several weeks.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    should I be trying for more run time,

    Keep in mind that I am a homeowner, not a heating professional.



    I favour as long a run time as you can get, provided you can get adequate heating under all conditions. Obviously, if you set the supply temperatures too low, you will get 24-hour per day run time and unless you are fantastically lucky, your comfort will be unacceptably cold.



    Now if you get a run time of 20 to 35 minutes and it is off for one minute in between those cycles (the worst it could be) I would not say you are cycling rapidly, so you do not need to do anything. It would have helped a little if you specified both the on-time and the off-time, but it will not make a whole lot of difference.



    Whether you should do anything will depend on a lot of things. My system is a mod-con with outdoor reset and most of the load is copper tubing in an on-grade concrete slab (probably uninsulated). For that zone, I spent a lot of time adjusting the reset curve to supply as low a temperature as possible consistent with getting enough heat. So my supply temperature to the slab is in the range of 76F to 120F, and I have never seen it get cold enough outdoors to go up to 120F,



    Adjusted as it is, it has already run 18 hours straight (once) and so far this year it has run 12 hours a couple of times. When it gets warmer outside, it runs shorter times (say 6 hours a day, and last Sunday, when it got to 70F outside, it did not run at all). The reason it will not run longer when it is warm outside is that the boiler will not modulate down far enough, so it must shut off because the thermostat becomes satisfied.



    Now with such a tight reset curve, you have to watch out for things. For one thing, even in my other zone (baseboard -- a lot of baseboard for the space involved) cannot use much setback because it takes many hours to recover from two degrees setback.



    Another thing is that if I die, and my heir who inherits the house wants to run it at 72F instead of 69F, it just might not be able to do it by raising the thermostat settings. All she would have to do is raise the reset curve three degrees, I suppose, but there is no way I could explain it to her. It would act as though it was an undersized boiler even though it is about twice the size it needs to be. And I do not really know if my present heating contractor would figure out the problem or not. These people do not seem to understand mod-cons or outdoor-resets. They understand the boilers OK, but not the controls.
    Adolfo2
  • ced48
    ced48 Member Posts: 469
    Thermostat-

    Design temp of 5 degrees, close to this at 35 minutes run time, more like 30/30 at 20 degrees, 20 on, 40 off at 35 degrees.
  • SWEI
    SWEI Member Posts: 7,356
    At or near design temp

    you should be running continuously, for several hours.  I have a few mod/con boilers showing less than 100 ignition sequences per year.  Try what I suggested above with the thermostat(s) and see what you get.
  • Le John
    Le John Member Posts: 226
    Wow

    that's 1 ignition every three days. My cast iron boiler will probably light 100 times every two or three days which must waste a whole lot of natural gas
  • ced48
    ced48 Member Posts: 469
    So, I Guess You

    would lower the water temperature (reset curve)? To clarify, the boiler is running about 1/3 to 1/2 of the time, and off the rest. Always shutting of at the thermostat, never at the boiler.
  • SWEI
    SWEI Member Posts: 7,356
    Correct

    Once you get the curve dialed in, the thermostat basically becomes a high limit controller.  If you locate it in a room that has solar gain or a woodstove it will become more useful.
  • Paul48
    Paul48 Member Posts: 4,469
    SWEI

    I like your approach. Very thought-provoking. Using it, you can tweak the reset curve perfectly.
  • SWEI
    SWEI Member Posts: 7,356
    Try it

    Remember, a conventional thermostat can only say one of two things: Either "I'm too cold" or "I'm too hot."



    It's far easier to manage the system if you know what curve produces a stable indoor temp.  Balancing room-by room temps hydraulically takes a bit of time, but it's worth it.
  • Paul48
    Paul48 Member Posts: 4,469
    Hmmm

    Once the curve can maintain a temperature, not gain on it, or lose from it, it has matched the heat loss of the structure.
  • SWEI
    SWEI Member Posts: 7,356
    Exactly

    With a properly sized mod/con feeding a well-balanced system, it can look a lot like magic.
  • Gordy
    Gordy Member Posts: 9,546
    Curt

    Have you encountered flywheel effects from weather where you have either a cold or warm trend that abruptly changes to the opposite.



    Μore so warm trend to an abrupt cold swing I would think. Would create an issue.
  • SWEI
    SWEI Member Posts: 7,356
    Flywheels

    are a constant challenge here with our winter sunshine.  Wind can also trick ODR into behaving badly.  I'm working on some controls which integrate a lot more weather data but it gets complicated - fast.  What I've been doing is to dial in the curve as best I can, take into account the weather conditions which accompany the adjustment period, and then add a few degrees to one or both ends to allow for some reasonably expected weather variation.  It seems to work.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Wow! is right.

    I sure wish I could hook up my computer to the U-control on my boiler so I could read out everything that shows on the front panel.



    I do not know the exact data, so let me make some up.



    Assume I have the heat on from September through May: 8 months. 240 days. But it does not heat much in September or May. My peak month, that is February, runs about 100 therms, and I run hot water with an indirect all year long. So in August, I run about 3 therms. If I count just the months that I use over 20 therms, that is November to April: 180 days.



    That means the slab zone might not run 24/7, but when it is cold it might run 8 to 16 hours a day. and perhaps only once, and not more than twice. So that might be one on-off cycle per day or 180 per year.,



    The trouble would be with the baseboard zone. Since the boiler is way oversize for just that zone, even though the thermostat would call for heat 2 to 4 times a day, due to the oversize of the boiler, it would come on for 5 minutes or so, go off for 10 minutes or so, or 4 cycles per hour (bouncing off the high or low limit of the boiler control). So if I need 8 hours of heat per day (my upstairs thermostat does not give me the total demand), that would be 32 cycles a day or 5760 cycles per year.  in addition to the 180 cycles per year for the radiant zone.*



    Ugh! Do not get an oversize boiler if you can help it.



    _____

    * I wonder if it would make sense to run the baseboards at a higher temperature than I do now. I have so much baseboard that I can have it run condensing all the time. (110F to 136F supply temperature). If I raised the curve some, especially when it is kind-of warm outside, It would reduce the number of cycles per hour because the baseboards would get rid of more heat whenever that zone was on. And it would warm the zone up in less time,so the thermostat would be satisfied sooner. Now I guess the temperature swings would be greater and the expansion noises would be greater, and the fuel efficiency would go down (loss of condensing). And the electrical efficiency would go up since the zone circulator would run less.



    See: If I could record everything going on with my computer, I might get enough data to calculate this all out.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    tune the ODR curve over the course of several weeks.

    That is pretty much what I did, though it took a lot more than several weeks because I could not adjust the outside temperature, especially at the cold end. I got my boiler in May, so I could not adjust much. I adjusted it using my calculations of heat loss, but that was not accurate enough. Then I had to wait until February to get a cold enough data point to set that end of the reset curve. And then wait for a pretty warm day to correct the other end. I mean it was really only a few minutes work each time, but multiple times. By the end of the first heating season, it was pretty close, but I fine-tuned it the second year.



    But anyway I am a homeowner with nothing better to do, so I did it. I assume you are a professional, and wonder how you could afford to visit a customer quite a few times in the course of doing this. Do you build the cost of that into the total job cost, like you probably do with the design and heat loss calculation? Or do your charge a service charge for each visit? Feel free to not answer this if you consider this information to be private.



    Aside from the fact that my installing contractor did not really understand the controls of the mod-con they sold me, and did not wish to even connect up the outdoor temperature sensor since they do not work well (sic). I did not even ask them to come back for this, I just did it myself.



    But you deserve to be compensated one way or another for repeated trips to the customer site to do this work.
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2013
    Proper sizing

    Of the boiler is the key, and control strategy.



    If you are lucky enough to find a mod/con who's doe matches your heat load at design conditions your boiler should run 100% of the time. Now if the same boilers modulation range matches the seasonal loads it will seldom be off.



    It's like taking a non stop trip in your vehicle. The trip is the heating season the car never shuts off, only adjusting its throttle for speed limits ( the change in load), and the occasional stop sign ( wws)) until it's destination is reached..... Spring!



    Now that is a top notch designers goal, and should be a an example to try to follow.



    Hats of to Curt!
  • Tom_133
    Tom_133 Member Posts: 883
    A little off topic

    Guys



    This is a very intriguing thread. I am curious, if you are shooting for less on and off cycles (as we all are), what effect does the cycles for hot water usage have on a combi boiler? I would love to have all my boilers get to the point where they only fire 100 times a year its much better on any equipment. It seems to me that if a combi turns off and on 30 times a day for heat and hot water its going to shorten the life span by quite a bit. Any thoughts?
    Tom
    Montpelier Vt
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Proper sizing Of the boiler is the key

    It sure is. Unfortunately at the time I bought my mod-con, I got the smallest one there was in the product line sold by my installing contractor. 80,000 BTU/hour input. It can turn down to 16,000 BTU/hour input.



    And I calculated that my house needed 30,000 BTU/hour with both zones calling for heat when it is 0F outside, and design temperature is 14F. So it is oversized about 100%. And worse if only the little zone (I have two zones and an indirect fired water heater), calls for heat: wants about 6250 BTU/hour when it is 0F outside.



    They make mod-cons a little smaller than what I have now, and some apparently turn down 10:1 whereas mine does only 5:1. So it is way cheaper to run than my old oil fired GE boiler from 1950 (about 70,000 BTU/hour with no modulation and no reset), but It could be even less I suppose if it were half the size.



    But I wish they made mod-cons for 1150 square foot houses.
  • Paul48
    Paul48 Member Posts: 4,469
    Horse of a Different Color

    The cycle time is more about efficiency than longevity, although longevity is an added benefit.All things being equal, there wouldn't be a difference between the stand-alone mod/con or a combi.
  • SWEI
    SWEI Member Posts: 7,356
    edited December 2013
    DHW calls

    The onboard controls are unfortunately crippled by having a single, static DHW priority temp.  The boiler responds the same way (186ºF or whatever it's set for) regardless whether the tank temp has drooped a few degrees over a few hours from standby losses or a few degrees in a few seconds from filling a large soaker tub.



    I've just started using outbord controls for this, using a PID loop reading the tank temp, modulating the boiler using 0-10V control.  This allows the boiler to fire only as high as is needed in order to keep the tank temp up and maximizes condensation.  When a large draw happens, the temp drops faster so the firing rate increases proportionally.
  • Paul48
    Paul48 Member Posts: 4,469
    Jean-David

    I know this has probably been covered 100 times, but....Have you reduced the max firing rate of the boiler, as low as you can, and adjusted the boiler circ accordingly?
  • ced48
    ced48 Member Posts: 469
    Back to My Original

    question, what is a realistic number of ignitions on an average winter's day in the northeast in a system like mine? One or two just isn't realistic in a retrofit situation, is it? Running water very much below 120 degrees in fin tube radiation seems to become ineffective. Is 1 ignition every hour, hour and fifteen minutes bad?
  • Paul48
    Paul48 Member Posts: 4,469
    Not Bad

    Could it be better?..YES, and everything written here should tell you that, and point you at ways to make it better. What is an affective temperature in the baseboards would become self-evident, if you did as SWEI suggests, and not look at the boiler as a bang-bang boiler.
    Daveinscranton
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    edited December 2013
    Have you reduced the max firing rate

    Sure. I cut it down to the rate at which it fires initially on start-up: about 55%. I do not know what the control would do were I to set it below the rate it needs to fire it initially. Mine now cycles only about 4 times an hour for my little zone and I am willing to live with that. I also widened the difference between the high-limit and low-limit around the reset curve so that is now 15F instead of the factory default of 10F. And I run that zone hotter than I would normally do so it dumps the heat faster into the rooms. Remember that lowering the maximum firing rate on a W-M U-control does not lower the minimum firing rate at all, and that would be what I would like to do.



    The reason I set the maximum firing rate down is because the servo (PID) has too low a damping ratio, and it is not user adjustable. So on firing, it rushes up to maximum firing rate and it discovers it went way too high too late to correct by reducing the firing rate, so it shuts off on high limit. It then did the same at the low end, so it was running bang-bang instead of anything nearly proportional (where it would fire at minimum firing rate). With my adjustments, it slowly rises until it hits the upper limit, then slowly decreases until it hits the lower limit, etc. for an acceptable cycling rate.



    But I wish I had a boiler half the size that mine is. Even then a 10:1 turn down would be better.



    And it cycles much less than that for my large radiant slab zone. When it is cold enough out, that does not cycle at all, but wanders around a little without hitting the limits.



    P.s.: I have done nothing with the boiler circulator: it is the one supplied by the manufacturer.
  • Paul48
    Paul48 Member Posts: 4,469
    Maybe

    You answered this, but, have you been able to effectively reduce the max firing rate of the boiler? If yes, then the boiler circ could be down-sized to match the max btus available, and stop feeding the excess heated water, directly back to the boiler.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    have you been able to effectively reduce the max firing rate of the boiler?

    Yes, but.



    I have three thermostat inputs to my boiler, and each has its own reset curve and most other adjustments.



    The boiler comes with the maximum firing rate for all these set at 94%. Older ones were set at 96%.



    For the thermostat hooked up the the indirect water heater, I left the maximum firing rate at 94%, since I had no reason to change it. I did set the target temperature to 175F instead of the default 190F because my hot water needs are small. A 30 gallon indirect would do the job, but I got a 40 because the price difference, compared to the price of the whole job) was trivial. I lowered the temperature because I hoped to get a little more condensing, and sacrificed the recovery rate that is always high enough for me.



    For the thermostat hooked up to the radiant slab, the greatest load (24,000 BTU/hour when it is 0F outside), I lowered the maximum firinig rate to 90%. I suppose I could lower it even more, but see no point because it rarely goes up that high anyway because the outdoor reset and the control itself tend to keep it lower to match the need.



    For the thermostat hooked up to my small baseboard zone, I set the maximum firing rate to 55% because the servo is a bit unstable with such small loads. With the firing rate lower, the low damping ratio is less of a problem.



    " If yes, then the boiler circ could be down-sized to match the max btus

    available, and stop feeding the excess heated water, directly back to

    the boiler."



    Other than the electrical cost of running the existing circulator (Taco 007) I do not see much point in changing the circulator. that would cost me the price of a lower capacity one and the labor charge of swapping it out. So what if the heated water comes right back into the boiler? The boiler would reduce its firing rate if it could do that in order to maintain the desired temperature in the system loop that the reset curve demanded.



    And if it could not reduce its firing rate because the boiler is too big,  what difference would it make if the excess hot water remained in the boiler, or went around the boiler loop?
  • SWEI
    SWEI Member Posts: 7,356
    Tuning the ODR curve

    sorry -- just re-read this and realized I missed your question above.  For a basic mod/con install, we plan on two follow-up visits after the initial commissioning.  One after a few days (or weeks) to make adjustments to things like the ODR curve, DHW settings, etc. and then a one year service (re-check combustion, gas pressure, re-flush and re-fill on older systems, etc.)  We build the cost of these into the contract.



    If the owner or their maintenance person are comfortable with making adjustments, we encourage them to do so -- but I have to mention that most boiler controls put the ODR settings in the same security level which unlocks a bunch of things they should NEVER be adjusting.  Given that almost all of of this information is available online, we can't really do much to prevent an overly adventurous owner from mucking things up.



    On larger jobs where we are providing controls, we utilize indoor feedback to adjust the ODR curve so the system "learns" as it is used.  Since everything runs as P-code, any adjustments we want the operator to have must be explicitly exposed via a UI that we control.
  • Paul48
    Paul48 Member Posts: 4,469
    None

    As long as the family doesn't mind huddling around the boiler to watch TV.The whole purpose is to make the heat, and move it to the system. Best Wishes

               Paul
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    None As long as the family doesn't mind huddling around the boiler to watch TV.

    "The whole purpose is to make the heat, and move it to the system."



    Of course.



    I thought we were talking about when the demand was so low that the boiler would not modulate low enough for continuous circulation, so it must go into bang-bang mode against the limits, with the duty cycle varying to get the proper heating rate.



    And when it is in that condition, pumping some of the hot water around the boiler loop will not get the rest of the house too cold. So no one will need to huddle around the boiler watching the bar graph showing the modulation rate and the target system supply temperature, the actual supply temperature, and the actual return temperature.



    The system loop will run at the desired temperature (on the average). The boiler loop will not get down low enough at low demand times. And at those times, it makes very little difference whether you run some hot water around the boiler loop slower than you otherwise might. If the boiler loop is insulated, it would just make it seem as though the boiler held four quarts of water instead of the actual three.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    most boiler controls put the ODR settings in the same security level

    My boiler hides just about everything, but it is a simple matter to read the installation manual and find out how to get to the ODR reset curves, It happens that it gives access to everything else too. Which is fine with me, but I imagine it would be unwise for the average homeowner to fool with them. In fact, the average homeowners I know do not even know how to adjust the temperature setting of a simple wall-mounted thermostat. They use it like an on-off switch. They think turning it up makes it heat faster, and turning it down makes it cool off faster, I have used a system that used a proportional thermostat (a finger moving up and down a resistor) and a motorized mixing valve when it was necessary to hold temperature very accurately with a very tiny (1/10 degree F) dead zone, but such applications are rare.



    I wish it gave access to the damping ratio of the PID controller, but I notice that these controls were already far too complicated for the installing contractor to manage, and my new contractor for service does not know how to use them either. And unless you know quite a lot about feedback control systems (I designed those things in a former life) I would not want to let a technician get access at all. On my boiler, there is no way to adjust that. You would have to modify the U-control board and I am sure Weil-McLain would not want the headaches they would get with support if anyone could touch that.
  • Gordy
    Gordy Member Posts: 9,546
    Jean

    I think you have tweeted your system as much as possible from reading your many posts.



    Basically there is about 150 days a season that require heating in the Midwest

    Depends say late Oct. to late march 5 months.



    So out of 30 days Curts designs go off line and refire 20 times a month avg.

    You'll never come close to that with out a boiler to fit the loss, and an eccentric mind for developing control strategy for the system.
  • SWEI
    SWEI Member Posts: 7,356
    Damping and feedback

    -- basic concepts we learned in high school electronics shop, both still quite relevant when talking about the physical world.  May also apply to the financial world, perhaps to a degree which many might like to deny.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    edited December 2013
    I absolutely agree.

    "Damping and feedback

    -- basic concepts we learned in high school electronics shop, both still

    quite relevant when talking about the physical world.  May also apply

    to the financial world, perhaps to a degree which many might like to

    deny."



    I absolutely agree. But you cannot expect politicians and news reporters to attain the level of expertise you have. They are not interested in reality, but only in getting re-elected and obtaining the perqs of elected office. They have not been educated; the politicians have only a law degree.  And the so-called reporters are just groupies that like to associate with the class of people they will never be a member of.



    You must have had an especially good electronics shop class. When I went to college, they did not get to feedback control systems until Graduate School. But the college I went to was not especially good at engineering. I learned most of that on-the-job where I associated with a small group of exceptional electrical engineers, some of whom designed automatic airplane landing computers.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    You'll never come close to that with out a boiler to fit the loss

    Actually, I do come close to that with my radiant zone (needs 24,000 BTU/hr on extremely cold days). At such times the boiler may receive a call for heat in late evening and run straight through until late the next afternoon, then not run until the next day. This can amount to less than once a day. It is not often that cold around here for an extended time though. But about twice a day it fires up anyway to keep the indirect comfortable, and the little upstairs baseboard zone wants heat, and that little zone is the problem. I have lots of baseboard up there, but not enough that I can use radiant slab temperatures in the baseboard to provide much of the heat.



    I actually do that. When the radiant slab zone has priority and is heating with the radiant slab reset curve, if the baseboard zone wants heat too, I allow the water to go through those baseboards. It does provide some heat to the zone, so it does not cool off as fast as it normally would, but it will not maintain the desired temperature indefinitely that way.
  • Gordy
    Gordy Member Posts: 9,546
    Tracking your loads

    I think one would be shocked at how low loads actually are compared to a heat loss program.



    If you are fortunate to have a way of tracking a systems run time (heat call) in a 24 hour period. You can't when calculate the heating degree days per square foot each and every day. Usually within reason that sf load is pretty much linear baring extreme wind loads, set backs, extreme ventilation, and solar gains.



    I have been doing this daily for my own home with a generously oversized boiler for the last couple years now. You can back calculate off of the numbers to see your btu requirements for a design day or even. Lower.



    Usually and it's been said many times here programs are 15, 20,and even 25% padded.



    In my case with an average insulated 50s construction 2000 sf ranch with four masonry fireplaces, 35% glazing.

    Calculated loads is 80k. Using HDD formula is about 58k.





    Most of the season is going to average 35k. Daily



    Mod/cons like working up hill.clawing at the heat loss to be replaced. I always believe in getting the most performance out of any piece of mechanical equipment it's designed for that is money well spent.



    Now most designers do not have the luxury of monitoring a structures energy consumption so interpolating the programs, and the variables they have as tools is part of the game.



    So how many cycles per hour? Is cycles per hour a good gauge even?



    I think if the equipment, and system is properly designed to a T rarely will it be off.



    Other scenarios if you can burn at least 10 min to achieve a good efficient flame would be a minimum. Anything more is getting better.
  • Danscrew
    Danscrew Member Posts: 130
    Efficency /Offtime

       I hear what you guys are saying. But where is the line drawn comparing run time to off time. If it satisfies the House in a certain amount of time and shuts off isn't that efficient? When its running and its in condensing mode with return temps below 130 that is prime Efficiency correct. I know there is a bunch of other variables involved.

     House temps satisfied and the boiler off is that the most efficient time for the Boiler?

    Running a WM 97-110

     I would like to lower the Min Btu from 22,000 to 14,000 I looked into the parts breakdown on the WM -110 and the WM -70 and the only thing that is different on the two boilers is the pri/sec circulator.  The venturi gas Orifice from a 040 to a 027 all that needs to be done is change the software setup in setup from the 110  to a 70 and change the cartridge on the Taco pump to one from the 70. That would lower my low end for my basement zone and i know my hole house is not more then the Max 70,000 the boiler puts out . Where can I buy just an Honeywell orifice and not the gas valve and the venturi housing together from Weil Mclain .thanks for all your help Dan 
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    I think if the equipment, and system is properly designed to a T rarely will it be off.

    That is what I try to do (almost). In fact, my reset curve is ever so slightly hotter than that, but I would like the thermostat to be off only 1/4 of the time and in one big block. In other words, on 18 hours, off 6 hours. The reason for that is if the wind outside is too great, it leaks a bit into the house, increasing the heat demand some, and when that happens, the system can just call for heat the other 6 hours and keep up.



    This does not work on my little zone though. I could probably do it if I could modulate down to 600 BTU/hour in that zone though.



    "I think one would be shocked at how low loads actually are compared to a heat loss program."



    I do not know about shocked. I was surprised at how low the heat loss of my house calculated out to be. And experimentally, it seems to be less than I calculated. I blamed the difference on the inaccuracies of the inputs I used for the old Slant/Fin program, not the program itself. Because I know only in general terms what the construction of my house is. Walls are 2x4s on 16 inch centres. They had so-called builders batts in there, but they do not do much, so I had them filled with urea-formaldehyde foam. But I do not know about how the corners are constructed, nor much about how the windows (Marvin) are framed.



    It was pretty clear that my old GE boiler was oversized even though it had a 1/2 gallon per hour nozzle in it. It took a lot of adjusting to get it to cycle slower than 45 seconds on, 90 seconds off. It must have been a pretty good piece of machinery to withstand that. The original GE burner (an amazing device) quit, and the heating contractor put a 70,000 BTU/hour input Beckett flame retention burner in it. That lasted from about 1976 to 2009, and it was still running then. I set the temperatures low (130 to 140F) so there was probably a lot of condensing in there. Used up vent pipes, but the 60 year old boiler never leaked.
  • Gordy
    Gordy Member Posts: 9,546
    Theoretical

    Dan can't really argue the fact that a boiler which is off is efficient.



    Of course I'm speaking theoretical......so far in boiler, and control management offerings to date that's not possible, but it's a goal.





    One always has to shoot for perfect, and like I said getting the most out of equipment investment is efficient also. When a boiler is off you don't need it either. The day Will come of infinite boiler modulation, and much lower minimums. Sipping minimal amounts of NG, or LP an hour to where shoulder seasons are matched with no off times, and very little fuel to do it.



    This thread kind of turned into what's theoretically a goal to achieve verses real world. But it should be a design goal/ even passion.
  • Danscrew
    Danscrew Member Posts: 130
    Gordy anything on last Paragraph ?

    Gordy

            Anything on the last Paragraph changing the orifice to smaller?  thanks Dan
  • Gordy
    Gordy Member Posts: 9,546
    Can you sacrifice

    Your top end output?



    Your basically turning the boiler into the 70 which means the total output will be lower not just the low end modulation. Unless you get a cold snap, and swap everything back.





    Or unless you want to experiment. Having the option to go back to original setup. Not sure but I don't think the warranty will be honored.