2 days ago my water got scorching hot on the hot water side. The next day I had no hot water. Checked the breaker, it was good. But the reset on the top thermostat tripped. A little bit of research led me to believe the thermostat was bad and overheated the water then tripped the reset. Went to Lowe's today, bought the kit with new thermostats and elements. Figured I would freshen it up. Drained the tank, install was fairly simple and straightforward. Turn everything back on, no sparks and no leaks. About 2 hours later I had water running out of my laundry room. Cleaned up about 5 gallons of water, turned the thermostats down about 10 degrees (they were on 125). An hour later the PRV was open again pouring very hot water in the laundry room floor. I determined the water is getting hotter than it should and the PRV is doing its job. I'm lost. Did I buy a faulty thermostat? Could it be something else?
Thermostat problems?
- Thread starter Pgoss8
- Start date
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Do you have city water? Do you have a Pressure reducing valve? Do you have an expansion tank?
While it does sound like the tank might be overheating, I would want to check what the water temperature is actually getting to. The T&P safety valve is designed to open at 210 degrees, or at 150 PSI.
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A good thermometer. Not the dial type that you get with turkey fryers, those are notoriously inaccurate.
Nearest faucet. Anything more than what the thermostats are set at is too high.
Ok. I'll turn it all back on tonight. Hopefully I can get it warmed up and check the temp before it blows off again. Getting tired of cleaning up water haha. If the relief valve starts pouring water again, what is the best way to get it to stop quick? Cut the water supply and open faucets?
If there is no floor drain at the TPRV discharge tube (or discharge tube run to the outside), simply place a bucket under it to catch the overflow until the problem is found.
...sheesh...Shut the cold water supply valve, open the hot water faucet @ the laundry sink and cut the power.
Ensure the WH is fully filled and the system burped before restoring power.
How old is the WH? It may be a defective TPRV.
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...hmm...
While reading on this subject, I came across this-
Found within this website- http://inspectapedia.com/plumbing/Electric_Water_Heater_High_Temp_Cutoff.php
I think... ...if the TPRV opens because of an overheating (and resultant excess pressure) event, that the incoming cold water will cool the heated water in the WH and give some relief. It it keeps spitting, something is very wrong.
The safety switch should trip if a continuous overheating event and is not only a weak TPRV opening because of resultant excess pressure also,
While reading on this subject, I came across this-
Found within this website- http://inspectapedia.com/plumbing/Electric_Water_Heater_High_Temp_Cutoff.php
I think...
...if the TPRV opens because of an overheating (and resultant excess pressure) event, that the incoming cold water will cool the heated water in the WH and give some relief. It it keeps spitting, something is very wrong. The safety switch should trip if a continuous overheating event and is not only a weak TPRV opening because of resultant excess pressure also,
If municipal water, most likely there is a PRV @ the meter, and even with no free standing PRV in the system, the lack of an expansion tank may cause the TPRV to open (result of thermal expansion).
You need to (IMO) to put a 24hr test on system water pressure along with a water temp reading. When the TPRV opens, the water being exposed to air temp will be @ boiling while the actual water temp in the WH may be less.
richardcohen
New Member
A thermostat is designed to shut the temperature of the water off when it reaches the chosen temperature, but if the heat-sensing device goes bad, then the water temperature will continue to climb until the backup thermostat shuts off the power. Both thermostats need to be tested to see which one has failed. You will probably need a professional to pull it out and replace it. Also, you need to test the element.
An element is tested with an ohm meter; a small current is passed through the element to see if it is unbroken.
Central Heating Specialists
An element is tested with an ohm meter; a small current is passed through the element to see if it is unbroken.
Central Heating Specialists
