Of Topic but, you guys are smart. Water heater relief valve

I have a water heater that is leak free and has a new top thermostat/maximum temperature cutout. Problem is that the pressure/temperature relief valve is opening and has been dumping off and on over the past three weeks. Opened early in the week and today at least. Top element is set at 125 degree F. Bottom element is set between B and C on a A/B/C/D scale. Water comes out of the kitchen faucet at about 125 degrees F. This is at a farm house I rent to a young couple. Can the temperature/pressure relief valve go bad? Never had the problem before. Since the water heater is probably 10 years old and the well produces hard water do you think I would actually be able to unscrew the relief? Looks like a pipe might screw into the tank. The breaker opened today as well, but that might be due to water splashing into the wiring/elements. Renter has the element covers off. Those will go back on tomorrow. The plumber that installed the water heater didn't extend the relief valve to the floor. That will be fixed tomorrow also. Fortunately the water heater is in the basement near a floor drain. Are there other issues that can cause the relief to open either due to heat or pressure?

I think most of the are replaceable.

They can go bad but their main function is to blow off when the temperature and/or pressure get too high. So not just temperature but pressure as well. Have you tested the water pressure in the house? The temperature may only be 125 but if the well pump has gone off the deep end, or in the case of municipal water, the pressure reducing valve has failed, you could be starting off with excess cold water pressure which is only exacerbated by heating the water.

At 10 years old this water heater is probably beyond its life expectancy. I would not hold out much hope for the TPR valve coming out of the tank, especially if there is hard water. Plan on replacing the tank sooner rather than later, and have a contingency plan in place before you start trying to remove that valve. In other words call your plumbing supply and make sure they have a replacement heater on hand just in case you need one.

I should have added that the house is on a well with a pressure tank. When the water heats and expands it should just push back to the
bladder in the pressure tank. Pressure tank is set at 45 psi.

If you are sure the pressure and temp are not too high you can replace the T&P valve cheaply from the big box store.

I've replaced a couple. Like any relief valve spring, they can weaken. Even though they say to trip them once a year, it does weaken the valve once it is tripped. Those calcium hardness crystals can keep them from closing tight. Try some limeaway and then wd on the threads and see if it will break loose. Might need a 24 and cheater. Be ready to buy a new if it doesn't come off. If an intermittent leak then you can buy time with a pvc extension to the floor drain. Next time around I am going tank less. More bux but then I can take longer showers.

Yes, they wear out. We used to carry spares on each service truck. Replacement is quick and easy.

If you go electric tankless those showers will actually be much shorter unless you like to alternately freeze and scald while showering. Voice of experience. TDF

Yup replace the relief Valve. Once they lift for what ever reason, especially in hard water, they will lift at a lower temperature.

We have hard water and I have replaced two of them.

One in the house and one in a RV.

Both came out fairly easy.

No more problems after we installed a softener.

"...Next time around I am going tank less. More bux but then I can take longer showers..."

On the two plumbing forums I read the professionals love those because they need a lot of expensive TLC - and they refer to them as "thankless" heaters from the customer perspective.

(quoted from post at 07:56:02 12/26/20) "...Next time around I am going tank less. More bux but then I can take longer showers..."

On the two plumbing forums I read the professionals love those because they need a lot of expensive TLC - and they refer to them as "thankless" heaters from the customer perspective.

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My experience with some high end commercial tankless water heaters is that they needed attention but mainly due to hard water. Tankless heaters are often undersized so the don't keep up. The industry, in the last few years has switched to constant pressure pump systems in new construction and replacements. Constant pressure pretty much eliminates temperature swings, And if you team that up with a boiler mate instead of a conventional water heater you can have the dragon pretty well tamed.