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Dry returns are getting hot

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rsel04
rsel04 Member Posts: 36

I have a Richardson 2 pipe vapor system running on low pressure with a vaporstat installed. Boiler pressure stays pretty low but on very cold days, the dry returns on 3 of my radiators get very hot. Initially, i thought it might be the crossover trap venting into the dry return that failed but I was able to confirm that it was not the culprit.

I'm aware that the Richardson radiators are supposed to have a water seal and ball check in the return elbow. I'd assume pressure needs to build up pretty high to blow through the water seal but Vaporstat is set to cut out at 8oz. which I don't think is getting triggered since I don't see pressure gauge going over 3-4 ounces.

The boiler is cycling more often with the frigid days so I was wondering if maybe the larger radiators are staying hotter for a longer period of time and that additional heat is being just conducted to the dry returns by the steel piping rather than steam.

Would appreciate any thought/suggestions.

Thanks,

Rich

Comments

  • mattmia2
    mattmia2 Member Posts: 16,117

    the condensate is hot so they will get hot but they shouldn't get as hot as the mains. the radiators shouldn't be steam hot quite all the way to the return. if it is then the metering device in the valve is open too far/too big(don't remember what kind of valves richardson uses, if it is a metering valve with a stop or a separate adjustable metering valve in the valve body or if it has a built in orifice).

  • mattmia2
    mattmia2 Member Posts: 16,117

    looks like it is a valve with a stop. try turning the valve on the radiators that are hot all the way to the return a notch or so less far open and see if that changes things.

  • Jamie Hall
    Jamie Hall Member Posts: 27,060

    And do remember that the condensate is still hot — approaching steam temperature — when the system is running hard. It's a bit disconcerting to feel a nice hot return, but unless it is really steam hot — almost impossible to judge by hand — it's probably just that it's running a lot of condensate. But do try @mattmia2 's suggestion.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • rsel04
    rsel04 Member Posts: 36

    Thanks everyone. I will try the suggestion from @mattmia2

    While I'm here, is there an easy way for me to validate my vaporstat is functioning properly? Just want to make sure it's cutting out properly in case my pressure gauge is off.

  • mattmia2
    mattmia2 Member Posts: 16,117

    compare them to another gauge or make a monometer out of a piece of tubing filled with water.

    rsel04