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need seasoned radiator pro for this one

darc2020 Member Posts: 1
I live in a beautiful 85 yr old house with two floors.  All the radiators work perfectly..can't touch them for too long, as they're so hot......except for one!  But, it is a large 5' x 3' radiator on the first floor that has NEVER gotten so much as luke warm for the last 10yrs that I've lived here.  My system is a gas powered, closed hot water system with an excellent pump.  I have tried bleeding the radiator and here's what happens:  just out of curiosity I bled it for a long time, to the point where both the inflow and outflow pipes were extremely hot to the touch.  The top 2/3 of the radiator gets hot, but the bottom 1/3 is always cold.   An hour later the entire radiator will once again be cold.  Is this a case of sludge build up in this one radiator? Do I have to drain the entire system to clear this problem up or is it worth putting some type of chemical in the system?  This radiator is cast iron and probably weighs a lot......HELP!!!! 


  • Steamhead
    Steamhead Member Posts: 16,733
    Check the shutoff valve

    is it open or closed? If you can't turn it by hand, call a pro!
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • furnacefigher15
    furnacefigher15 Member Posts: 514

    Not likely a sludge issue, at least not in the radiator. Most likely a water flow, or balance issue. May also have a closed valve.

    I would imagine if there were that much sludge in the system, this would be a more universal problem.

    I would have someone look at it.
  • tim smith
    tim smith Member Posts: 2,743
    Re: radiator that won't flow

    Start shutting the radiators around it off, this will direct more flow and see if it starts flowing. It may have been repiped poorly and an air lock is in the pipe. We have gone so far as to shut all the radiators off in houses/bldgs to get a loop to force the air out. Do one at a time starting around it and when it starts to flow, you might just try opening the ones that are off up 1/4 to half. May have to do this on quite a few as there is not good balancing avail on these old pipe systems. Make sure the valves don't leak when you turn them or you could damage floors/ceilings etc.  If valves have not been opened/closed in a long while, they very likeley could leak at the valve packing nut.
  • billtwocase
    billtwocase Member Posts: 2,385
    may also be

    a balancing problem. Is is furthest from the boiler? Your heat cycle may be ending before the radiator has time to exchange water. It may also be a piping problem down below. Sounds like hot water is entering from the supply and return for that radiator when you bleed it, so my guess is the valve is open, and it is not "gunked" up. I would echo calling a pro. Out of curiosity, what thermostat do you have? System zoned for 1st and 2nd floor? GPH, or amperage setting on thermostat? Have you tried to throttle down some of the other radiators that are close to the thermostat?
  • nugs
    nugs Member Posts: 77

    How is the system piped?  Is it a mono-flow system or two pipe reverse return?  If it's monoflow there are a couple things that can be causing the problem.  One is that there is not enough space between the monoflow tee and the feeder tee so the water just passes right on through without the venturi doing it's thing.  You need a couple feet between tee's the other is that something has plugged in the venturi opening of the monoflow tee which can be flushed out by reversing the flow in the system. 
  • icesailor
    icesailor Member Posts: 7,265

    I had a customer with that problem. The system was installed in 1963. One radiator that went to a second floor bedroom had no mono-flow tee, There was a set of unused monoflow/regular tee plugged off and one connection should have been in a spare moniflow tee.

    Mark off all your pairs and make sure that you don't have something like that.
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