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1 unit out of 19 is not heating up. Underradiated?

Abracadabra
Abracadabra Member Posts: 1,948
19 unit building.  All apartments seem to heat well.  1 unit does not.  I've just gone thru the building and revented every unit, including all mains. Radiators in the unit that's cold heat up quickly and all the way across. I've attached a chart showing temps across 7 units, along with the building average and outside temp.









I've sealed up all windows with window film.  All doors are weatherstripped.  No other significant air leaks can be found.  The temperature slope of the unit that is always cold is similiar to the other units, so I don't think it's an heat loss problem.  No radiators have been removed from the unit.  I'm thinking I need to add a radiator or two.

The unit that's cold is the 5003-1 (greenline)

Any ideas?

Comments

  • crash2009
    crash2009 Member Posts: 1,484
    ?

    Green was keeping up until the cold snap at 201.  Green never recovered after that.  Green should have got right back in line after the cold snap.  You missing any water?
  • crash2009
    crash2009 Member Posts: 1,484
    Orange and red

    What did you do to Orange and Red at 226?  They didn't fall the same way as the rest.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    chilly apartment

    is this unit on the top floor? is steam arriving at all the radiators simultaneously?

    don't bother about the room temps first; concentrate on the radiator temps. if you have good simultaneous steam arrival, then perhaps the radiators are a bit small--but why?--nbc
  • Abracadabra
    Abracadabra Member Posts: 1,948
    orange and red (and turquiose)

    orange (1966-2)

    , red (1962-2)  and turquoise (1968-2) got taken out of the building average at about that point, but that doesn't explain the slower heat loss on those units.  Insulation on these apartments is non-existent.  It's basically a 12" brick wall with lathe/plaster interior walls.  5003-1 and 5003-3 are on the same riser.  1 is the 1st floor, 3 is the 3rd floor.  Those apartments are on the end and have 3 exposed walls.  The weird thing is that the 5003-3 unit, which is the absolute furthest from the boiler is actually doing quite well.  What I've noticed is that as it gets colder outside, the temps of most of the apartments get closer together, instead of more spread apart.  The only one that's really giving me a heartache is that 5003-1 unit.
  • Abracadabra
    Abracadabra Member Posts: 1,948
    cold apt is 1st floor

    nbc, the cold apartment is on the 1st floor.  The 2nd and 3rd floor apartments are actually warm and heat up nicely.  The 1st floor LR radiator is quite large and shares the takeoff with the 2nd and 3rd floor LR radiator. The 1st floor BR, DR, and Bath radiators have their own seperate takeoff for each rad.  The 2nd and 3rd floor shares risers for the BR, DR, and Bath. Not sure that makes sense.  I can whip up a quick drawing if it doesn't.  Let me know.
  • crash2009
    crash2009 Member Posts: 1,484
    Stacked Radiators

    I had some difficulty with the one stacked/shared riser in this building.  Not sure this applys to all stacked rads.  I had to vent mine exactly the same.  I tried many different combinations and ended up with a Ventrite #1, opened to the max on both, to get both rads to heat at the same time.  This might apply to your LR1, LR2, LR3.  Mine is only stacked 2 floors, 1-Bath and 2-D.  In my case I had to equalise the exit pressure between the two rads for them to share the steam in the riser. 



    Recently, Steamhead replied in a post that he prefers to size the main venting using the 1 oz scale.  I asked him why.  His responce was vent the mains using the 1 oz scale, the risers using the 2 oz, and the radiators using the 3 oz.  The reasoning on this was 1 oz encourages the steam to fill the main first, 2 oz fills the risers second, and 3 oz fills the rads last.  This implies that there are three areas of venting, that require their own specific CFM. 
  • Abracadabra
    Abracadabra Member Posts: 1,948
    venting

    crash,







    Ya, I saw where Steamhead posted that and added those notes to my "cheatsheet" :-)  I've been doing venting adjustments, but in the end, the radiators in the cold unit are all heating up properly and the same time as the other units, all the way across. The only other solution I can think of is to undervent the other 18 units to get more and longer steam here, but that seems counter productive efficiency wise.  The largest radiator in this unit is fed off the same riser as the 2nd and 3rd floor units, which is strange when you look at the rest of the piping in this building.  Every other 1st floor radiator has it's own takeoff and riser.  Only the 2nd and third floor units share a takeoff and riser, which is consistent with every other 1-pipe steam system apartment building I've seen around here.  The 1st, 2nd, and 3rd floor radiators share a takeoff which then is teeed off and feeds the 1st floor.  Not sure if that makes sense.  I've attached a bad sketch here.  I'm not an artist, sorry.  Most radiators are piped like the stack on the right.  
  • Mike Kusiak_2
    Mike Kusiak_2 Member Posts: 604
    Radiators sized to heat loss?

    If the radiators in the cold apartment are heating up quickly and all across, then it doesn't sound like a steam distribution problem. Whats different in this apartment? Is it larger or does it have more outside wall area (corner apartment)? Are the radiators smaller than in comparable apartments?



    My guess is that apartment is underradiated and you need more EDR to meet the actual heat loss.
  • Abracadabra
    Abracadabra Member Posts: 1,948
    ...

    The unit has 3 exposed walls, but so do the 2nd and 2rd floor units.  2nd and 3rd floor units are fine temp wise.  Basement below is unheated, but so is the ceiling above on the 3rd floor unit.  The 3rd floor unit does have larger radiators( 2-4 sections more per rad, i think to take into account heat loss thru roof), but the 2nd floor unit has same size rads as 1st floor.  I have the total EDR for the rads at the building.  I'll post them here tonight.
  • Mike Kusiak_2
    Mike Kusiak_2 Member Posts: 604
    Radiator sizing

    With the unheated basement below, I would think you would need the same size radiators as the third floor, rather than the second which has a warm ceiling and floor.



    Don't assume that the first floor apartment ever was right. It might have always been cold. When fuel was cheap, standard procedure was overheat the other apartments so that the coldest was comfortable and the rest would open their windows!
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