Hi, My grandmother's electric hot water flooded the basement a few days ago. When she discovered the problem, the entire basement was sitting about ankle deep. The water was coming from the pressure relief valve. I went to lowes today and bought a new valve that is the same size, psi, and temp setting as the old valve. My question is, the old valve states 100,000 btu and the new valve states 105,000 btu. What does this mean and will this difference cause a problem? Thanks!

For your safety's sake, the most important question needs to be addressed; What Caused the original pressure relief valve to open?

I'm not sure what orginally caused it to open. I just assumed it was time to replace the valve. I have talked to some other people and they are saying that the tank could have over heated and popped the valve. If that is the case, wouldn't the valve have closed once the temp and pressure in the tank dropped with the loss of water for an extended time? The entire basement was flooded so the water must have been coming out for awhile. I just figured that with the water running that long the temp should have gone down enough to close the valve. Am I missing somthing? I'm open to all suggestions!

It opened because of temperature or pressure that was too high. Is the house on a city water supply with a pressure reducing valve ?

Yes the house is on a city water supply and I'm assuming it has a pressure reducing valve sinse this is the first time this has happened and the house been built for 30+ yrs.

NC is right, the safety valve on the water heater is a T/P (temperature/pressure) valve.
Since you are on a city water supply, you could have a bad PRV (pressure regulator valve)

If you put a "lazy hand gauge on your system overnight and it "spikes" above 80 psi, your PRV could be bad.

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a little off topic but if I remember t and p is 150psi, 210 degrees- it may be different down south- but a t and p is a t and p. Is this a boiler? cause then btu is relevant?

If it were temperature that opened it, then it should have closed when the water cooled down, unless the valve also failed. If pressure opened it, it would NOT stop until the pressure dropped to its low setting, but if you are on a city system with high pressure, that will NEVER happen, so the valve will run "forever". If that is the problem, it should happen with the new valve also. Check your water pressure.

quote; I'm assuming it has a pressure reducing valve

Bad assumption, because NOT having one is more likely, unless you are in a high pressure area.

The btu is irrelevent, as long as it is HIGHER than the heater's input capacity, which for an electric heater is very small.

a TPRV should be tested / 'worked' ANNUALLY as a minimum

if left 'static' they will become 'sticky' over time

side issue: why did the floor drain not work ? if no floor drain HAVE ONE INSTALLED as per code

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