HW Relif Valve Problem

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    • #274893
      Avatar photoMasterPlumbers

        Why is my new hat water tank relief valve leaking. I have a 10 year old, 50 gal. “Jetglas TTW Energy Saver” gas fired tank rated to run at 150 PSI…recently the Watts 150 PSI 10,000 BTU relief valve started leaking/dripping. I replaced the valve with another Watts valve of the same type…the leak continues…What gives? (I tried draining off water from the bottom of the tank to dislodge any setiment..but that hasn’t helped)

        Thanks in advance for any input.

      • #290685
        Avatar photoGuest

          BTW…I also reduced the temperature by draining off the hot and turning down the thermostsat…

        • #290686
          Avatar photoSylvanLMP

            You had better have a licensed master plumber check this out before you have a slight explosion or a ruptured tank Hey good luck

          • #290687
            Avatar photoGuest

              Thanks for the input so far…however…I’m really looking for some insight into the potential problem..

              If its not a DIY operation what could be the matter?

              What is a master plumber likely to tell me is the likely or potential problem?

              If a repair is doable? If so what is the repair and how much will it cost?

              Or do I likely need a replacement tank?

              Thanks again for your consideration.

            • #290688
              Avatar photojhollo

                You will have to install an expansion tank on water heater.This is a new thing and sometimes is caused by a town or city installing valves at the water meter.

              • #290689
                Avatar photoGuest

                  OK…so I installed a 40# expansion tank inline to counteract the check valve (even though the check valve has been installed since the house was new in 91) and after the local plumbing supply guy told me that probably the temp senser calcified and not operating properly…seemed to make sense…but now the RV is leaking as much as ever…checked the water temp of leaking water and it is nohere near to hot…valve stillo leaks when water is running… now I see a post about possible problems with Watts valves..ladies and gentleman …what is your verdict?

                • #290690
                  Avatar photoSylvanLMP

                    Just installing an expansion tank is not really the way to go.

                    As a LMP we check the actual BTU input of the heater and actually water the gas meter to make sure they match up.

                    We also check the specific gravity and heating value of the local gas supplier.

                    Throwing in expansion tanks and by passes and PRV’s is the handyman way of guessing.

                    Again I will strongly suggest you call in a professional as even though your T&P is doing its job you are putting undue thermo stress on this pressure vessel.
                    A T&P is not designed to be an operating controller.
                    Have fun

                  • #290691
                    Avatar photoSylvanLMP


                      Originally posted by jhollo:
                      You will have to install an expansion tank on water heater.This is a new thing and sometimes is caused by a town or city installing valves at the water meter.

                      Expansion tanks are really not a NEW THING as I am working on buildings over 80 years old that have “expansion tanks”

                      As far as valves at the water meter The US Post office has FISH TRAPS and PRV’s installed at the meter since the very early 1900s in lower Manhattan.

                      Pressure temperature relationships are nothing new.
                      This tank and piping arrangement should be checked out before there is a major problem.

                      It is like when a pipe ruptures we try to find the cause before we just replace a section.

                      There maybe a cold water relief valve some where in line not doing its job.

                      The actual burner may have become defective allowing too much fuel to heat this unit.

                      The operating control could be encrusted with mineral deposits.
                      There could be a lot more reasons this valve is failing and just throwing in an expansion tasnk does not find the cause of excessive pressure.

                      Without knowing the actual volume of this system how do you pick which size expansion tank to use?

                      Do you use a bladder or non bladder type?

                      What pressure do you set this expansion tank at or is it one size fits all?

                      Again calling in a professional cant hurt.

                    • #290692
                      Avatar photoGuest

                        Well…thanks again for all the advice…but no one has yet to hit on the answer…which is…ta da…a defect Watts T & P valve…after my last post I went to Sears, purchased a different brand T & P valve, installed it and voila…all fixed!!! : )


                        FYI…the expansion tank is an Amtrol Therm-X-Trol bladder type. Putting a tire guage to the in-service tank showed a system 75 psi…the pre-charged bladdertank checked out at 40 psi pre-installation…

                      • #290693
                        Avatar photoSylvanLMP

                          Great going Chuck, now just make sure if you ever have to recharge this bladder type expansion tank you do it isolated from the system.

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