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1st floor won't heat but upper floors do-why?

are you saying all the first floor radiators are hot but that the second floor is overheating and the first floor is still cold? if so it sounds like convection air currents carrying the first floor heat up..the house itself can act like a chimney also..try hanging a curtain between first and second floor at the top of the steps.. or close a door if it has one..this would pretty much tell you.

Comments

  • GW
    GW Member Posts: 4,676
    1st floor won't heat but upper floors do-why?

    Hi guys,

    I'm stumped on this one job we did back in September. 12 new rads, 4 per floor. All on TRV, all home runs to a manifold. Constant circ with outdoor reset, 2.0 curve, 190* or so high limit. Obviously there are many more details I could mention; I'm hoping this won't be rocket science. 1st floor rads are a bit larger, so I'm open to some flow rate issues. I'm using a 26-64 pump, 1/2 fosta-pex.

    The house was cold on the first floor. It's an early century house. The basement is insulated, 1st floor joists that is. The heat loss program I use has been very reliable, so I'm thinking it's a house issue.

    Is there any phenomenon causing heat to stack up and leave the first floor struggling? Actually, there are still two rads on the 3rd floor that have still not been installed yet, no paint on the wall, I guess.

    Thanks for any clues,

    Gary


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  • when you say

    the first floor wont heat, do you mean the radiators aren't hot or it seems even with them its still cold?
  • jim lockard
    jim lockard Member Posts: 1,059
    froze

    Gary--Can you isolate and purge the 1st floor loop? Maybe It was not being used and froze up along the outside wall?
    The upper loops would continue to heat, but the 1st floor will get nothing.Best Wishes J.Lockard
  • GW
    GW Member Posts: 4,676
    heat

    Nothing is froozen, all he first floor rads are cranking. I tried purging, they're all filled up with water.

    still stumped,

    GW

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  • jim lockard
    jim lockard Member Posts: 1,059
    me too

    Gary Wilson --the 1st floor supply tempture is? the 1st floor return tempture is? outside tempture? 1st floor tempture taken from the center of the largest room is?
    As Gary G suggested close off the stairway from 1st to 2nd floor. Do you have a ceiling fan or box fan that can stir up the air? maybe try that. Your very sure that the heat loss cal. is correct? recheck for air leaks around the permeter of home. Does the house over hang the basement? Best wishes J.Lockard
  • GW
    GW Member Posts: 4,676
    yes,

    that's what i was thinking too. I've never run into this, so now that you mention the chimney theory, I know I'm not nuts.

    Thanks, we'll give it a try.

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  • GW
    GW Member Posts: 4,676
    reply

    I guess anything is open for discussion, the heat loss loads have treated me very well over the years, so I have reasonable doubt that it's the calcs.

    The house is on a full basement. Again, this is an old house, I'm sure the basement is very leaky. What gets me id I've never seen this on other jobs, although I'm usually just heating one or two floors, 3 floors is uncommon for my small operation.

    The temps are running nice and hot, the delta T is useles w/o the gpm, if I have to I'll connect some gages to the fore and aft of the circ and calcualte the head loss/gpm.

    My guess is we're stacking the heat to the top of the house. There are no house fans. Thanks for the help,

    Gary

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  • What about insulation between floors ?

    I have a similar problem in my own home - it's usually much hotter upstairs in the winter . Would insulating between the 1st and 2nd floor stop heat from flowing up ? Is there much heat flow through the floors ? My house right now is 3/8 sheet rock with furring strips holding up ceiling tiles . The floor joists are 2 by 8 with no insulation . The upstairs is 3/4 ply with carpeting on top .
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928
    TRVs on all the rads?

    That does sound really odd.

    Where are the TRV sensing elements located? If the upper floor rads are on outside walls (particularly under windows) they could certainly be influenced by a cold draft making them "think" the room is cooler than it really is.

    Danfoss recommends against using TRVs with self-contained temp sensing elements when they are installed on the bottom connection of rads. Such placement exposes them to drafts--often magnified by the radiator itself. If for some reason you're getting a whopper of a warm convective current up stairwells and through rooms that warm air is likely well above the floor level. If it's cool down where the TRV sensor is located it will open and only add to the problem.

    You could try turning all of the upper TRVs down (relative to the first floor) considerably and see if things are more balanced. This isn't a solution but a possible way to pinpoint a problem. You also might want to take some air temperature measurements--near ceiling downstairs; near floor upstairs; "breathing line" upstairs; near ceiling upstairs; etc. Big temp differences will likely guide you to the problem.

    TRVs are somewhat "relative" in the room temp produced at a given setting but it shouldn't be too great.
  • in a wierd sort of way

    i would say insulation between floors would NOT help.. cause the temperature differential is actually the other way around..the higher floors are hotter and the lower floor is cooler..heat flows from hot to cold...okay here is my theory,,i have no basis on education for this, its just a theory..most homes around my cleveland ohio area have a third floor, and ive noticed this problem often..the senario is that on mild days, the upper floors are cooler than the first floor..on really cold days the upper floors are hotter than the first floor..my thoughts are that on a mild day, the radiators are hot for only a short spurt of time and transfer heat by radiation with not enough time for serious air convection currents to start..on real cold days the radiators are always hot..convection currents can now form and heat the air as well as the radiant effect heating surroundings..the heated air rises of course..this rise is aided by the increases differential between the third floor temperature and the outside of the roof temperature...at zero outside temperature the rate of heat loss should be double that of 35 degrees..so i would think the rate of inside heat movement must be double also...of course the third floor is still getting heat from its own radiators as this is taking place...like i said, its just a theory...
  • GW
    GW Member Posts: 4,676
    i agree

    it makes sense to me.

    These rads are always hot/warm; consant stratification affect.

    The house is comfortable in the 20s, but in the single digits the first floor suffers.

    Gary

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  • thats why i like

    hot water systems that can zone each and every room with their own pump..ive been doing some studying on ''mean radiant temperature'' that siggy touchs on in his book and also the following web site..makes zoning each room make even more sence to me. meanradianttemperature.com/
  • alanm
    alanm Member Posts: 71
    2nd and 4rd floor very warm

    Need help. House about 100 years old, 3 stories, one pipe system, thermostat in 2nd floor hallway.
  • alanm
    alanm Member Posts: 71
    2nd and 4rd floor very warm

    Need help. House about 100 years old, 3 stories, one pipe system, thermostat in 2nd floor hallway.

    Problem: example, thermostat set at 72, third floor is that , 2nd floor same , but first floor is about 68.

    What can be done to make first floor more in line with temperature on 2nd and 4rd floor.

    Thanks.
  • GW
    GW Member Posts: 4,676
    you may want

    you may want to start another thread, you'll get more replies! It looks like you're having the same problem I am, can you block off the first floor from the second and see if that helps?

    Gary

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    Gary Wilson
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  • GW
    GW Member Posts: 4,676
    wow

    a circ for each zone... I think we're talking about two different animals here- a constant circ rad job with TRVs is completely different that a typical BB system

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  • hi gary,

    yup, i'm just thinking outload that, that was why i liked zoning, cause alot of problems can be avoided..most systems around here are whole house systems also..and their particular twists that drive you nuts..
  • Boilerpro_3
    Boilerpro_3 Member Posts: 1,231
    Heat loss more than doubles at 0 than 35 degrees,

    Due to chimney effect. Take a look at the manual load calcs. For a medium tight home, the number of Air changes per hour at 35 F is about .75, at 0 F it is 1.1. Heat loss due to infiltration increases 135% not 100% from 35F to 0 F, and since the first floor is where the cold air typically comes into a structure, this is where most of the increase of infiltration for the WHOLE STRUCTURE takes place. That's alot of additional load on the first floor The heat loss programs I've seen dont take into account where a space is located in the structure.

    If you look at what the dead man did, the rads on the first floor where usually 20 % bigger than on the second, and this was when the second floor rads had to be sized to account for the heavy losses through uninsulated attics, where the first floor rads didn't.

    I always add additional loss to lower floor rooms and also on the windward side. If it is a completely radiantly heated home, you can probably add less to the first floor heat loads than if you're using warm air type heating (ie. scorched air furnaces, convectors, high temperature cast iron).

    Heat loss program calcs are a starting point, they need to be massaged for reality.

    Boilerpro
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Really sounds strange Gary...

    Have you checked your cv ratings and delta-p in the system at design conditions? TRVs (like other devices) have increased pressure drop with increased velocity.

    A low delta-t across a TRVd radiator implies higher output and higher velocity. High delta-t across a TRVd rad implies lower output and lower velocity.

    I suppose that the boiler isn't firing continuously at the cold outside temps. If it is firing nearly constantly (and your reset curve isn't already "maxed" at that outside temp) you could increase the reset ratio and/or base temp. If burner is cycling well but you're still not getting enough heat it would tend to point to some sort of flow issue...

    I'd compare the delta-t across rads both upstairs and downstairs.

    If delta-t is relatively low and consistent between the floors it would imply that the TRVs are delivering near max flow and the rads near max output at that temp. Solution would be to raise supply temp if possible. The TRVs should compensate by reducing flow & delta-t upstairs.

    If delta-t is relatively high and consistent between the floors it would imply a general circulation problem: circulator defective or too small; TRVs undersized; branch piping undersized; manifold undersized; etc.

    If delta-t downstairs is consistently higher than upstairs I believe this would imply a circulation problem causing too little flow downstairs: "weak" circulator; undersized TRVs/piping downstairs; balance problems at the manifolds; etc.

    If delta-t is downstairs is consistently lower than upstairs it would imply undersized radiation downstairs.
  • GW
    GW Member Posts: 4,676
    Thanks BP

    That makes sense, I talked with the owner today and seems there are still a few old steam pipe holes that still need to get plugged up in the basement, and I guess there's an old pipe chase that is sucking some big draft up out of the basement- so I think we're on the right track.

    I always wondered about beefing up the second floor on AC due to stacking, but I never thought about loading the 1st floor on Heat- I will certainly keep it in mind for future mulit-stories.

    Thanks,

    Gary

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