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Boiler Not Keeping House Warm

Yes. I have doors that isolate the front entry vestibule (stairway) to the upstairs proper. These are always closed during winter.

I called the boiler installer and he had me set one of three dials from just below "5" to just above "5", then I set the other dial (aquastat) from 160 to 180 (he said this can go to 200 or 220). He said I can set it back down when it warms up a bit. He said if this does not work to give him a shout.

It's been over 40 minutes since I did that and it's gone up two degrees, from 60 to 62. The temp is set at 70. I have my fingers crossed that in the next hour I'm staring at 65 or 66. I really hate that it takes so long to pick up a degree or two.

Also, thank you so much to all who have taken the time to reply, it's deeply appreciated.


  • jacksonista1927848jacksonista1927848 Member Posts: 12
    Boiler Not Keeping House Warm

    Hello everyone,

    In April of last year we got a new hot water boiler and baseboard radiators installed in the house.

    Our house is 1300 sq ft downstairs (zone 1) and about 1100 sq ft up (zone 2).

    The boiler is a Locinvar with Taco controls and has two zones (2nd and 1st floors) with a third being the basement (I have a shut-off from the boiler on the basement rad as I have only one down there and rarely use the basement). Anyway, We got some very cold weather in November and I noticed for the first time that the boiler was not warming the house up as quickly as it should. I set the controls to 62 at night and 68 during the day. This cold snap passed rather quickly and I forgot about it, but I did notice that it took the boiler a while to heat things up.

    Last night outdoors it got down to 4 degrees F, I know, that's cold, but the temp for zone 1 (downstairs) was set at 62 and it was reading 58 in zone 1; the boiler wasn't even keeping up with 62 on zone 1. It took the boiler all day (12+ hours) to go up eight degrees. It never made it to 68. The upstairs zone was set to 61 (because we sleep covered up at night and don't need it to be warm). The only time zone 2 is turned up is between 8PM and midnight and it's set to 64 degrees F.

    I'm really having trouble with this and I'm disturbed that I just got the system and we're unable to get warm. I'm no heat hog, as you can see, but for gosh sakes, it's hard to be comfortable in 58 degrees and we didn't pay for that.

    I headed to the basement to check things out. We have a hot water system. Our boiler is a Locinvar and has Taco controls on the side. The boiler is a model CBN090-Input Rating of 90,000-Output BTU/HR of 73,800.

    I noticed when I went to check out the boiler that when the flames come on, they stayed on for a short while (8-10 seconds) and then shut off. The gauge on the side of the boiler read about 150 degrees F before it kicked on, and when the flames shut off it read 170 degrees F. I waited another minute for another cycle and that time it got down to 150 degrees F and turned off at 165 degrees F. Is this cycling too fast?

    The boiler has never heated up quickly and in Michigan (I live in south central Mich) we have plenty of cold days. Even on the more temperate days (highs of 28 and lows of 15), it takes a long time for the boiler to reach 68 degrees F.

    I'm planning on calling the contractor tomorrow to have them come out and look. However, I'd like to know what may be the cause prior so that I'm not handed a load of bunk. BTW, during the house remodel, every single exterior wall was insulated with R13 (it's an old house) and we have about 7 inches of insulation in the attic. We also got all new double pane Andersen windows. Man, I'm cold....
  • MIke_JonasMIke_Jonas Member Posts: 209

    Could be a ton of things, too many to list. You trusted him to sell and install this system, you should trust him to make it right, right?

    If you were my customer, the first thing I'd ask is have you ever tried NOT setting the thermostat back?

    I would ask the contractor to supply you with the load calc he used to size this boiler. I do one on every job and turn it over to the homeowner when the start up is finished.

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  • oil-2-4-6-gasoil-2-4-6-gas Member Posts: 641

    you should not set-back your thermostat in the coldest days
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    Setting it Back

    Okay, yesterday I reprogrammed the thermostat to a solid 70 degrees F. This morning at 5:30 it's reading 57.

    So what I'll end up doing, in order to get the kitchen from being 50 degrees F (which is what the thermometer is reading in that room) means that I will have to turn burners on on my stove. This is so darned backwards and frustrating.

    Thank you for your comments. I'll be calling the contractor this morning and I'll ask them to come out. I'll also request a copy of their analysis used in determining system size, etc.

  • GWGW Member Posts: 2,583

    Is the boiler running non-stop? Can u see what the temperature is at the boiler?

    "Nothing" has changed with your house?? Nothing at all???????? No added heat loss, cable tv guys running around your attic? Do you have any ice dams hanging off your roof?

    ahh i just re-read the OP. Remodel????? Get a blower door test and IR camera guy there if you heating guy seems convincing. I've been in HIS shoes before, only I have those specialty tools I just mentioned. It's not always the heatings guys fault!!!!!!!!!!!!!!!!


    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    Gary Wilson

    Wilson Services, Inc

    Northampton, MA
  • Brad WhiteBrad White Member Posts: 252
    What we do not know...


    You mention baseboard radiation and boiler size, but we do not know how much actual radiation element you have- Is it up to the task? Do you know the actual heat loss versus the radiation you need to offset that?

    What has me thinking this is the short-cycling of the boiler.

    Picture a boiler in a house with all of the radiation it needs. Water leaves at say 170, comes back at say, 150 and it all keeps going.

    Take the same system and cut the radiation in half. Your water temperature will not drop like a full radiation array would do. The water will return too warm, satisfy the boiler and shut down.

    When you have less radiation output potential than the boiler can handle/drive, it wastes the boiler's capabilities. It strives to emit heat but the radiation may not be enough to do it's part.

    For that boiler output, I would expect to see at least 125 linear feet of element, if not more. This assumes about 600 BTUH per LF by the way.

    Also, if it is piped in series, too generously, one end may be hot and the return end may be too cold, exacerbating the effect. I really do not know, just tossing out ideas and things that I have seen too often.

    This is not to cast the installer in a bad light, but rather, let's eliminate what it is probably not, first.

    I am not saying that you have 50% of the radiation but the fact that water that hot is not getting you closer to target has me thinking along those lines.

    Gary Wilson has a very good point too. Just insulating is not enough, especially if it is just batt insulation. How "ideal" was the installation? A 10 percent gap can lose 30-40% of R-value. Air sealing is crucial.

    As Gary said, it may not be the heating guy, it may be the house, but it also could be a combination of things. By the size of the boiler compared to your presumed heat loss and SF, I do not think it is the boiler. Suspect radiation.
  • Dennis FoleyDennis Foley Member Posts: 21
    You need to have a professional evaluate the system

    My subject says it all. Any answers here are just educated guesses. You need to call the installer back, and if he can't evaluate and fix the problem, you need to hire a professional who can do the heat loss calculations, examine the system and explain what is happening and what can be done about it. Saying it's the boiler is just a guess. It could be all or a combination of the things that others have mentioned, plus circulator sizing, pipe sizing, piping details, faulty equipment, poor boiler piping practices, and etc.
    Hire a pro.
  • S EbelsS Ebels Member Posts: 74
    Could be this could be that.............

    Here's one thought..........Do you have a door that isolates the second floor from the main floor? I've run into cases where the second floor is turned down to 60 and the owners are trying to heat the main floor to 70 and it won't happen. This is because the hot air is rising to the second floor leaving the first floor "undersized" for what it's trying to do, which is basically heat both floors. If you have a door at the bottom or top of the stairs close it and see what happens.

    Obviously, if the boiler is cycling on/off there is less load on it than it's capable of providing. How many lineal feet of active fin tube to you have?

    I have -18 here this AM up in the Cadillac area. Bet you're not having much luck this morning. :(
  • tim smithtim smith Member Posts: 2,226
    Pat. one important piece is where are you located, You may

    be well below your local design temp per ASHRAE and now the boiler/radiator system is beyond what it was designed for. This is just a possibility. If outdoor temps are well below normal lows then this is very likely and nothing was done wrong. If you read threads here, we all try to size pretty close to design heat loss on houses for efficiency sake and this can be a little issue in 100 yr low temps/once in a blue moon, if thats the case.
    Sidenote, my guess is this is not the case as when you turned your boiler up to 180 the house is getting up to temp and the boiler was cycling off at 180 so it is doing the job although.
  • Mark EathertonMark Eatherton Member Posts: 5,584
    Quick math shows...

    Your boiler is roughly the right size. Around 30 btu/sq foot per hour.
    First, if the house is dropping significantly when you are in set back, its an indication of a need for tightening up the envelope. That will cause human discomfort.

    THe fact that the boiler short cycles indicates some other "problem", and it could be something as simple as air binding, r lack of output element, or improper piping.

    First thing I'd do is have it checked by the installers to make sure there are no slipping clutches, low tires or plugged air filters.

    Second thing I'd do is get rid of the set back program when it is cold outside. Losing proposition. You have no "EXTRA" capacity in this system for it to recover real well during cold weather.

    It obviously worked well before. What (other than the boiler) has changed?

    Cuddle for warmth :-)

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • GWGW Member Posts: 2,583

    that means a leaky building.

    Before I did this thermal envelope training i thought I knew everything there is to know. Wow, isn't life all about knowing what you don't know?

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    Gary Wilson

    Wilson Services, Inc

    Northampton, MA
  • tktk Member Posts: 36

    I would try turning the aquastat uo to 200º while it is cold. You mentioned the boiler shuts down at 170 I believe. Maybe the system was designed for 200º. If it works you can turn it back down after the cold snap.
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    It was -14 degrees Fahrenheit in Jackson

    I'm in Jackson. It was 14 below, not including windchill. Brrr! Come on spring!!!!
  • The Boiler Dr.The Boiler Dr. Member Posts: 163

    Minus 32F @ home this AM Wind Chill Factor -47F
    125 miles north of Grand Forks
    It was colder yesterday though and it should warm up in 3 months Gotta luv it!
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    Good Grief!

    Guess I better quit feeling sorry for myself and get those wool socks on! Oh, and grab a heating pad while I'm at it.

  • Paul FredricksPaul Fredricks Member Posts: 315

    Sounds like you might be on the right track. Remember what was said above, what I tell all my customers: When it gets really cold, leave the thermostat setting in one place!
  • Mark CustisMark Custis Member Posts: 539
    We still

    would like to know about your heat emitters and the short cycling.

    How many feet of baseboard do you have?
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    Footage of Baseboard Fin

    I measured approximately 85 1/2 ft. of baseboard fin. This does not include the shop radiator that is in the basement, it hangs from floor joists and has a fan. Over the top of this baseboard fin in some rooms there was a second layer of copper pipe running along the top, this double layer ran for approximately 37 1/2 ft. total.

    Does this make sense what I'm saying?
  • Brad WhiteBrad White Member Posts: 252
    Feet of Element- I think you need more....

    Per my original post and what you just added, my gut check still says that you do not have enough element. I do not think it is the boiler, but let's take a look.

    Your heat loss, assuming the boiler net output meets it, (73,800), divided by your SF (2,400), gets you to 30.75 BTUH per SF. That is "within reason" as a check figure only.

    EDIT: Mark Eatherton said as much- I agree with him.

    (I would hope you would have a calculation to back this up; from here in Boston, I am doing what I can :) so hoping you can work with me here...

    But as stated, I would hope you would have at least 125 LF of baseboard, assuming an average of 600 BTUH per LF. That would get you to 75,000 and max out the boiler.

    Now, you say that you have 85.5 LF of element. If your heat loss is the 73,800, then your baseboard has to emit 863 BTUH per LF on average. This rivals the output of some commercial baseboard.

    That part with the pipe within the cover helps a bit, but not much to take credit for it.

    Do you have a rating output, type, manufacturer, etc?

    I really think you need more element.
  • Mark EathertonMark Eatherton Member Posts: 5,584
    Mackwords Bath....

    Based on Brad's above statement, it would appear that you have been fiddle faddled by the fickle finger of fate, or dibbled by the dirty digit of destiny...

    In other words, the original designer used a MUCH higher water temperature when they designed your system.

    Go to

    There, you can see that in order to get 863 btu/linear foot, you will need average water temperatures of around 230 degrees F. Not a good idea...

    You'd be miles and dollars ahead to do as much energy conservation as you can... and as you have seen, increasing the water temperature does help, but it will also drain your pocket book via the gas meter.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    I guess

    I just got used to my old 50 year old boiler, I'd turn up the thermostat, and it'd respond and heat up my old radiators, the only problem was I did not have any heat upstairs and figured during the remodel would be an optimal time to upgrade and do the whole house. And that old thing heated up the downstairs in a house that had zero insulation in the walls! Ice dams be damned!

    The house is now up to 66 degrees, the thermostat is set at 70 and I'm leaving it there. We have two more nights of below zero before we catch a break weather-wise.

    I am planning on having the boiler installer come out and see if there is some other reason the house is not heating up well, even with the changes he had me make earlier. He said to call if we are still low heat-wise.

    So the gist I get from some of the posts is that there is (probably) not enough baseboard to dissipate the heat from the pipes and therefore it is returning water that is still too hot so the boiler shuts off feeling that it does not need to heat the water further?

    I don't like that fickle finger of fate!

    Images of the boiler can be seen at this link:

    Oh, and the temp just went up another degree to 67F, and this is while the temps outside are dropping. It's 5F here right now with a windchill of -13.
  • Noel KellyNoel Kelly Member Posts: 42

    "The gauge on the side of the boiler read about 150 degrees F before it kicked on, and when the flames shut off it read 170 degrees F. I waited another minute for another cycle and that time it got down to 150 degrees F and turned off at 165 degrees F. Is this cycling too fast?"

    A few thoughts.

    The short cycling might be indicative of absence of heat transfer i.e the hot water is leaving the boiler but the Btus are not leaving the emitters. Are the baseboard elements unobstructed? You must have good air flow over the elements - no furniture in front of baseboard or wall to wall carpeting. You should have at least a 20 degree delta across the loop. Especially with your outdoor temps. Then again - as mentioned above, if there is insufficient radiation you may not be able to release sufficient Btus. Which means that you will have to increase your operating parameters - see below.

    What is the rating of the baseboard? Is it high output or low?

    You mentioned a rad in the basement. Make sure that this is excluded from the loop as it will suck down enough Btus to starve the main loop. Then again, if this was the case your Delta T should be higher...hmmmm!

    All condensing boilers have programmable controls that allow tweaking e.g. changing reset curve. You may need a higher delivery temp - as mentioned before - and your installer should be able to make this change. I believe that this particular boiler control has a "Boost" mode that will override the curve if the heat call exceeds a certain time. It may be that you need to have the upper limit of this setting adjusted to a higher setting. Obviously this might impact the efficiency of the boiler but for the relatively few days that it is required, this is not a major concern.

    Noel Kelly
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    -12 degrees Fahrenheit this AM - 60 degrees F in house

    Well, the thermostat dial hasn't moved for two days from 70. The aquastat was set up to 190, the house is 60 degrees F.

    I'm not sure what is wrong and today the contractor will be called to the house to figure it out. I realize that because the house is a hot water system, the temps won't go up as quickly as forced air, but when it takes 8 hours to go up six degrees, there is a problem.

    I do believe it isn't the boiler but lack of sufficient footage of baseboard radiator. This of course makes me extremely unhappy as I don't know how this would be remedied except for major adjustments.

    I am a person who feels that, even on abnormally cold days, I should be able to turn up the heat and be able to get the house to a livable temperature (at least 68) as this is how it has been in any other dwelling I've lived in.

    On average, my kitchen is about 10 degrees cooler than the rest of the house, another indicator that there is not sufficient baseboard in there.

    Finally, I'd like to say thank you to all who have assisted and given ideas. Thankfully, I still have six months of my 1 year warranty with the contractor.

  • mikemike Member Posts: 161
    copper fin boiler

    Is this a low mass copper fin boiler? If it is not piped primary secondary then the boiler will short cycle due to BTU's not being able to escape before the high limit switch shuts off the boiler.
  • PerryPerry Member Posts: 141
    I'm guessing that the biggest change is this... and the fix is..


    I am sure that one of the things you are wondering is why your old boiler keot your house warm - and the new one does not. I doubt that you actually reduced the number of radiators with the boiler change - and I doubt that the setting for water temperature greatly decreased as well.

    I have had a somewhat similar experience - although I can keep my house warm (by raising the circulation temperature 15 degrees on a design cold day). Fortunately, my boiler controls automatically raise the temperature to keep the house warm.

    The problem is that I cannot keep the basement warm as it has no radiators.

    What happened was I used to have a huge radiator in the basement - the old boiler. The basement used to be the warmest place in the house; and heat drifted upstairs to help keep it warm too.

    Now, the new boiler does not radiate at all - and the only radiator in the basement is a single loop of 1 1/4" pipe with 1/2" risers going to radiators on the 1st and 2nd floor of the house.

    The radiators for both the 1/st and 2nd floor of the house are sized to within 2 Ft total of the theoretical needed by the Slantfin heat loss / radiator selection program for 140 F water - on a design day.

    But, the basement needs about 12,000 Btu/Hr of heat that it does not get. Thus, the only way to keep the house warm is to increase the water loop temperature in the rest of the house to compensate for the missing heat in the basement.

    I am planning to install additional and appropriate radiators for the basement when I get the $ to finish the walls in the way I want to. I do note that when I installed the new boiler that I had 1" copper stubs put in on the monoflow-T circuit start and end so that I could add heat in the basement if needed.

    One factor to consider is that a good chunk of the basement heating requirement is not dependent on outside temperatures - and since I run my house heating on a reset curve (heating water temps from 90 F - 165 F), what I need to do is size the basement radiation so that it can be comfortable at say 110 F heating water, with the appropriate controls to reduce water flow for higher heating water temps (TRV's - or similar).

    So - how cold is your basement compared to the past. It is likely a lot easier to add heat to the basement than it is to add heat to the rest of the house.

  • Brad WhiteBrad White Member Posts: 252
    Warm-Up Times


    No doubt that many warm air systems seem to turn over the air and get up to temperature quickly. Hot water can do so also if you have enough element.

    I always design for a surplus, such that even 140F entering water will work. This allows you to run at a lower temperature year-round. Still, if your system were designed for 180F entering (say 170F average), this is still fine.

    That your kitchen is cooler is, as you say, reflective of a lack of radiation. Kitchens are tough that way.

    You could install a kickspace heater for the kitchen, given that the rest of the house has baseboard. They are compatible. If you do this, I would get that heater on it's own thermostat to run the fan and not use the clip-on aquastat.

    As for the radiation issue, another way to look at it is, "why have that much more boiler than you have radiation to distribute the heat?" I mean, maybe 10% is fine, but not having a 40% surplus.

    That all said, you are maintaining a reasonable temperature for your efforts. You can imagine how it can be with the requisite 125 to 150 feet. Faster responding, too.
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    Basement Radiator

    I have a large shop radiator with a big fan in the basement. This was originally in the house when I bought it. In fact, there was a second shop heater that didn't have a fan, it was quite a bit smaller. When I bought the house, it had rads on the 1st floor only (6 of them) and an old Homart boiler. I wrapped the copper pipes trying to keep that water warmer coming upstairs (the basement was very temperate). Later, when they redid the heating system, I was told not to wrap the copper as the runs help heat the floor above and also keep the basement warmer. It has not been bad cold-wise in the basement and the shop heater down there does an excellent job of taking off the chill.

    The basement windows are old, but all have been sealed with that styrofoam spray and this keeps drafts out. I have even been contemplating putting R-19 between joists where the hot water pipes do not run in an attempt to warm things up.

    I just know that I spent many dollars on the system and feel that when it's cold I should be able to get to 68 in a reasonable amount of time. I lived in TX for 20 years (I was raised in Michigan so cold is nothing new) and my sister says I'm a TX wimp who can't handle the cold.....

    I do realize however I can do more to insulate and I will act on this as time and money allow. Next winter, I will be even better insulated and prepared for the cold.
  • jacksonista1927848jacksonista1927848 Member Posts: 12
    Boiler Images at Flickr

    Follow this link for a look-see
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