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Help Diagnosing Several Radiators that are not Heating

Jane_DJane_D Member Posts: 14

I live in an old house (built around 1936) that was vacant for several years (2005 - 2014). It is heated with a gas boiler (bought in 2014), and a combination of cast iron convectors, traditional cast iron radiators, and fin tube units that were installed around 2011). At one point the house was vandalized, with the thieves taking some of the copper piping and some of the cast iron convectors (that is when the fin tube units were put in). When the house was vacant there was no heat, so it is possible that some of the remaining cast iron convectors could have cracked (that said, they are not leaking).

I am having problems with several of my radiators, and I am hoping that someone can help me determine an orderly process for figuring out what is wrong. The convectors and the cast iron radiators worked without problems in 2005. As mentioned above, the fin tube units were put in around 2011; it is unclear whether the ones that are not working now ever worked when they were installed.

1. The radiators on one side of the house:

There are three rooms one on top of the other that do not heat: the family room, a small dressing room above the family room, and the attic (obviously, the attic is not on one side of the house, but the radiator that heats the attic is directly above the dressing room). The family room has cast iron convectors, the dressing room has a fin tube radiator, and the attic has a traditional cast iron radiator. I am attaching photos of the convectors in the family room and the large, traditional radiator in the attic.

When I bleed the radiators, no water comes out of the cast iron convectors in the family room, and no water comes out of the cast iron radiator in the attic. Neither the convectors in the family room nor the radiator in the attic gets warm to the touch. Water does come out of the fin tube radiator in the dressing room when I bleed it, and it gets only slightly warm, but it does not get warm enough to heat the dressing room.

2. Two of the three convector radiators in the living room:

Two of the three convectors in the living room are not heating. My recollection is that water comes out of one of them when I bleed it, but it does not get warm.

3. The radiators in the upstairs den, over the garage:

There are fin tube units in the upstairs den. The room is above the garage. Water comes out when I bleed the radiators, but the fin tube units don’t seem to get very warm.

Can anyone give me any ideas on the steps I should take in order to figure out what is going on in all or any of these rooms/radiators?


  • JohnNYJohnNY Member Posts: 2,443
    Can you post a picture of the boiler and the surrounding pipes and pumps and stuff?
    For troubleshooting and private consulting services, find John "JohnNY" Cataneo here at :
    "72°F Mechanical, LLC"
    Or email John at [email protected]
    John is the Boilers and Hydronic Heating Systems Course Instructor at NYC's Mechanics Institute, a professional Master Plumber, licensed by The Department of Buildings of The City of New York, and works extensively in NYC while consulting for clients in and out of state.
    John also oversees mechanical installations and maintenance for metro-area clients with his family's company, Gateway Plumbing and Heating along with his brother/business partner.
  • Alan (California Radiant) ForbesAlan (California Radiant) Forbes Member Posts: 2,334
    edited August 2019
    It sounds as though there are a couple of things going on.

    1) There is probably some air in the system that is preventing proper circulation of water. Flush the system to remove the air.

    2) If no air or water comes out of the air vents at the radiators, there might not be enough pressure in the system. Check the gauge at the boiler. If your boiler is in the basement and there are three floors above, the pressure gauge at your boiler should be at least 20 psi.

    There might be some other things going on. Pump not working, etc. Hard to tell from here.

    Post some pictures of your boiler and the piping around it.

    What part of the country do you live in? Do you have someone that can service your system that has experience with hydronic heating systems? Usually the old guys know the most.
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • Jane_DJane_D Member Posts: 14
    Thanks so much @JohnNY and @Alan(CaliforniaRadiant)Forbes for the quick replies. I’m not at home, but will take pictures and post them tomorrow.

    @Alan(CaliforniaRadiant)Forbes, I’m afraid I don’t know what it means to “Flush the system to remove the air.” Is that what what happens when I bleed the radiators? At the start of the cold season, I always turn on the boiler and bleed all of the radiators.

    I have not noticed “air vents at the radiators.” Is the air vent the valve that one puts the radiator key into in order to bleed it?

    In terms of pressure, last year I had a problem with one of the radiators leaking. @JUGHNE and @Grallert advised me to check the pressure, and told me that it should be at 12-15 psi. I had it lowered from 25 psi to 12 psi and the leak stopped.

    If the pump is not working, why would some radiators in the house work and others not work? I live in the Washington, D.C. area. I have a company that services the boiler once a year, but they say they cannot work on/diagnose any radiator issues.

    As I said, I will take more pictures tomorrow when I return home.
  • IronmanIronman Member Posts: 5,641
    edited August 2019
    You need to call Dan Foley at Foley Mechanical in Lorton. He's the best in the business.

    He's on the contractor locator on this site.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
    Rich_49Erin Holohan Haskell
  • I think you need a different company to service your system. A qualified technician should be able to service and troubleshoot any problems you may have. Servicing without knowing how the whole system works is like trying to drive with your eyes closed.

    You asked how some radiators can heat while others not when the pump does not work. Water becomes more buoyant as it’s heated and can move to radiators upstream if the piping is vertical. However, if there are long horizontal runs or if the water has to move down, gravity flow will stop and the radiators on that branch will not heat.
    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • Jane_DJane_D Member Posts: 14
    @Alan(CaliforniaRadiant)Forbes and @JohnNY, here are photos. I am not sure, however, exactly what I was supposed to be shooting, so I do not know whether the photos capture what you were interested in seeing . . .

    @Alan(CaliforniaRadiant)Forbes when you say

    I think you need a different company to service your system

    Are you saying that Foley Mechanical is not the right company to call?

  • IronmanIronman Member Posts: 5,641
    I think Alan was referring to your present contractor, not Foley Mechanical.

    Someone who can’t service the radiators is not a hydronic contractor.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • Jane_DJane_D Member Posts: 14
    @Ironman -- thanks. It is just stunning how little I know/understand.
  • The tech's. at Foley Mechanical are top shelf.

    "It is just stunning how little I know/understand."

    Have a little patience and you'll know more tomorrow than what you do now.

    Often wrong, never in doubt.

    Click here to learn more about this contractor.
  • Jamie HallJamie Hall Member Posts: 12,863
    Oh no -- Foley Mechanical is assuredly exactly whom you DO want to call. They'll take care of your whole system and do a top notch job of it.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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