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Random Cold Steam Radiators

Hello. I have 11 total radiators in my house. Each time my boilers fires 10 of the 11 heat up just fine, but there is always one that stays cold. The one that remains cold, however, isn't consistent and is seemingly random from a pool of four. Could someone list out some of the various reasons why this might be? I'm really scratching my head here. Thanks!

Comments

  • Fred
    Fred Member Posts: 8,540
    Is this a one pipe or two pipe system?
    Are all the radiators on the same Main off of the boiler?
    Is that main properly vented?
    If this is a one pipe system,Do you have vents on the radiators that are fast venting allowing steam to go toselect rads?
    Is this a relatively new occurrance or has it always done this?
    Do you know what you total Radiator EDR is and what your Boiler rated EDR (Sq. Ft. of Steam) is?
    Once you tell alittle about you system, we may be able to help.
  • mcvetyty
    mcvetyty Member Posts: 50
    Sorry about that.. Here are some more details:
    • One pipe system.
    • Two mains, the four options for cold radiators are not on the same main (2 on each actually)....
    • The mains are vented pretty well. Two Gorton #2's on each. Could probably use another 1-2 but I'd like to think this isnt the issue..
    • Yes, I have a couple of radiators that are heating up quickly due to large vents and have actually considered this to be the problem myself. Was looking to see if someone on here might corroborate that theory. Do you think the two 'hog' radiators are stealing the others steam? It just seems odd that its not the same cold radiator everytime, no?
    • This has been an issue for as long as I have been here (past 3-4 winters).
    • The boiler is slightly undersized, but I dont think this is the issue because for as long as I have been here, even on the coldest of cold days, the thermostat gets satisfied well before any of the radiators are even 50% full.
    Curious to hear your opinions! Thanks in advance...
  • Fred
    Fred Member Posts: 8,540
    edited November 2015
    The first thing I would do is put smaller vents on those two radiators. It sounds like they are hogging the steam and if they are only heating half way across, in the coldest weather, the vents are probably never fully closing. Steam takes the path of least resistance and those are probably in that path. It is not that unusual for the cold rad to move around when the rad venting isn't balanced. Different circumstances can influence that, like how cold it is, how warm/cold the mains get between cycles, how long the boiler runs, which rad vents fully close and which may only heat half way across, leaving the vent open etc. It's important to balance the venting across all the rads to get proper steam distribution.
  • Abracadabra
    Abracadabra Member Posts: 1,948
    mcvetyty said:


    Yes, I have a couple of radiators that are heating up quickly due to large vents and have actually considered this to be the problem myself. Was looking to see if someone on here might corroborate that theory. Do you think the two 'hog' radiators are stealing the others steam? It just seems odd that its not the same cold radiator everytime, no?

    Yes. I've seen this happen in several situations. Vent the radiators slower. If your mains are closely balanced, it could be a variety of factors which determines which side starts condensing first and vacuuming steam from the other side.