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Water Leaking From Hot Water Relief Valve

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STvex
STvex Member Posts: 71
HI, Today I went to the boiler room and noticed water all over my floor. I attached three pictures. The bucket under the pressure relief valve was filled and overflowed. After I emptied the bucket water was still dripping from the relief valve. I tried to open the valve to see if it would reset but it still drips. The pressure reading is zero.

Common reasons why this would happen? I plan on changing the relief valve, expansion tank and pressure reducing valve. The zero pressure has me thinking the pressure reducing valve is letting water through. Any thoughts? I appreciate the advice.


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  • hot_rod
    hot_rod Member Posts: 22,341
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    yes to all three, replace the relief, check expansion tank, replace if water logged. Assuming it is a diaphragm type tank? The fill valve must not be allowing water into the boiler, it should go also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    STvex
  • STvex
    STvex Member Posts: 71
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    Thanks, is the pressure reading zero because there is no water in the boiler or because the boiler is filled with water? [due to bad expansion tank and/or fill valve]
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,735
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    @STvex

    If your into it that hard you can replace the triadicator. (pressure gauge /thermometer) or put a gauge on the boiler drain to check the pressure to see if the gauge is accurate
    STvex
  • STvex
    STvex Member Posts: 71
    edited April 2022
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    Thanks.  That Guage is brand new.  Do you mean garden hose Guage attached to drain valve?  That's excellent idea.  
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,735
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    @STvex

    Yes. It's just a way to check the gauge on the boiler without draining or removing the gauge.
  • HomerJSmith
    HomerJSmith Member Posts: 2,477
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    There are three reasons for water leaking out of the PRV.

    1. A bad PRV.
    2. An expansion tank that hasn't any acceptance (water logged). Shake the tank and note whether it feels heavy. Momentarily, press the tire valve on the bottom of the tank to see if water comes out. Any of these, replace the tank.
    3. The boiler fill valve (Pressure Regulating Valve) is bad and allowing boiler pressures to exceed 30 PSI, forcing water out of the PRV.
    STvex
  • STvex
    STvex Member Posts: 71
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    There are three reasons for water leaking out of the PRV.

    1. A bad PRV.
    2. An expansion tank that hasn't any acceptance (water logged). Shake the tank and note whether it feels heavy. Momentarily, press the tire valve on the bottom of the tank to see if water comes out. Any of these, replace the tank.
    3. The boiler fill valve (Pressure Regulating Valve) is bad and allowing boiler pressures to exceed 30 PSI, forcing water out of the PRV.

    Thank You!!
  • HomerJSmith
    HomerJSmith Member Posts: 2,477
    edited April 2022
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    I should have added: The expansion tank could still be good even tho it is water logged (feels heavy when shaken) because the air charge on the bladder air side is low or lost and water doesn't come out of the schrader valve on the bottom of the tank, in which case, one only need to recharge the air in the tank to 15 psi. This has to be done in a special way.

    Regardless, a leaking PRV should be replaced whether or not it is the cause of the leak because it can be damaged by a constant leaking situation.