Asked on Mar 29, 2012

What causes a pressure overflow valve on a gas hot water heater to intermittently drip.

Mr. Will.Plumber26Terry S


I replaced the valve and it still drips.
9 answers
  • Spikes in water pressure from your local water supplier. Get a pressure gauge and screw it to a couple of outside spigots to get a reading. If it is continuing to leak it usually indicates that the pressure is too high. Also check your inside pressure reducing valve to see what it is set for

  • KMS Woodworks
    on Mar 31, 2012

    Handy mentioned the basics...but these can also leak a bit if they have been "tripped". so the first trick is to get the cause corrected...then swap out the you know what you house pressure is?

  • Good point - I have noticed sometimes on the replacement release valves that they tend to stick open when tripped...not sure why. You may want to release the valve and see if it will reset

  • Larry W
    on Apr 1, 2012

    I don't know what the house pressure is. All of my neighbors are on the same city system and none seem to have this problem. I can see their "outlet" pipes sticking out of their garage wall and they are not dripping. I will try releasing the valve to see if it may flush out a piece of grit. The dripping seems to be worse right after an extended use such as a shower or a dishwasher cycle.

  • KMS Woodworks
    on Apr 1, 2012

    These items are not that pricey...about 12 to 15 bucks. If after a few attempts to get it working with out much luck I'd just swap it might even be able to return you old one as "defective" could be a crappy spring in there.

  • Larry W
    on Apr 1, 2012

    I'll try a couple of things later today or tomorrow. I'll post the results. Thanks for for interest.

  • Terry S
    on Apr 1, 2012

    larry i thought i was the only one with that problem. it is aggravating. mine is worse if i turn the water heater up. doesnt seem to be as bad if the water heater is set low , but the higher i turn it the worse it gets ..nobody can figure it out. we even replaced the water heater thinking that was it.hope you get figured out.

  • Plumber26
    on Apr 2, 2012

    it's from thermal expansion.... you need to have a thermal expansion tank or thermal expansion valve installed @ your water heater to cure this problem..... you'll spend $100 on replacing your temperature/pressure relief valve until you finally realize "this isn't working". if not good at soldering, call a plumber... should't be a very expensive service call (100-150 bucks)

  • Mr. Will.
    on Apr 4, 2012

    I've Replaced T&P Valve New that was bad from the Factory . It also can be to High Water pressure coming into the House. Get you a Water Pressure gauge about $13.00 which attaches to your outside Hose Bibb Front Yard which should be tied directly To your Water Service, before it goes thru a Pressure Reducing Valve to redure water pressure inside your hose. The pressure should read 55-65psi. Ihope this Info. help out Will B.

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