Water heater Woes

Frio39

Recently noticed my water heater leaking from teh CPVC attached to the T&P relief valve. Drained the tank and changed the valve, still leaking. INstalled a pressure gauge on the tank and when in use it spikes over 140 nominal pressure seems to run around 60-80. Thought of installing expansion tank but only have about 4 inches after the pipe comes out of the wall before it hits the cold water shut off, also can not find the main shut off for the house to even begin. Any ideas??

Sammy

I would check the thermostats for the upper and lower elements.

Sounds like either they are turned too high or one of them is failing causing the tank to overheat and blow out the TP.

Frio39

How would you recommend checking the thermostats??

Frio39

I have them both set to about 125 upper and lower

Sammy

Turn off the power and verify that its off. Tag it out if you cant see the water heater from the panel

Try pushing the reset button normally on just the top thermo and see if it is tripped.

Disconnect the wires from the heating element.

Set the thermostat to the lowest setting.

Measure resistance/ohms across the heating element wires coming off the thermo. You should get an open/no conductivity since the tank should already be hotter than the temp your calling for. Then try turning up the temp setting while watching you meter. It should show conductivity when it hits the tank temp. Do this for both upper and lower thermos.

Check your elements while disconnected by measuring resistance across the two element terminals. Should be 10-20 ohms for a good element.
Then measure resistance between each element terminal and the metal tank. Conductivity would point to a grounded element that will need replace.

AllanJ

If you have a thermometer that goes that high you can measure the hot water temperature directly after letting the water run awhile. Never run a glass thermometer all the way to the top or let it rise fast otherwise it could explode and send mercury or staining fluid all over the place.

Are the spikes to 140 PSI very short and only when someone turns the water off after using? Could be just the effects of water hammer but could still make a relief valve open momentarily. Somehow a standing (or ambient) 60 to 80 psi in your water system looks high to me and a pressure reducer unit on the cold water line just inside the house (before the meter if that is also inside) would be appropriate.

Sometimes the main shutoff is outside and perhaps buried in your lawn although it should have a control rod you can see. If that is the only shutoff, have another shutoff installed inside. A water heater should have shutoffs on both inlet and outlet.