Scenario: Water Heater, Pressure Building, Release Valve Stuck...

This was something I had always wondered about... The water heater is next to my room... Literally about 9 feet away... It's a gas water heater to boot... Probably the gas would not catch on fire, but you never know...

Wouldn't you know it, the MythBusters have tested this! LOL... cool...


Uh, thought I should offer some how to info on water heaters...

Both gas and electric water heaters have a safety device called a pressure relief valve. In the event the tank over-pressurizes, the relief valve opens and releases the pressure. If the valve does not operate correctly, the tank can over pressurize and explode.

Duh, now what do we do? Maintain!
Water Heater Maintenance

I just thought of something regarding this. Wouldn't the pressure (of steam) never be greater than around what your water pressure is, because if it exceeded that, it would start to push the water back through the supply line?

Originally posted by ben91069
I just thought of something regarding this. Wouldn't the pressure (of steam) never be greater than around what your water pressure is, because if it exceeded that, it would start to push the water back through the supply line?

I think the pressure will only build in the tank itself.. There is the release valve that should work if this every happens, but if it doesn't work the tank will potentially explode... It wouldn't leak back into your pipes because the pipes are already full of water and water can not be compressed, however the steam vapor can be... But you could turn your bath on or take a shower which would release some of that pressure I'm sure... But if you are asleep and the thing keeps heating it wouldn't take long before boom... I think in the video the tank reached around 350 PSI before exploding... Did you see how high it went into the air and what it left behind... That would scare the crap out of me or kill me one or the other for sure..

But you should send a message off to myth buster and ask them about this.. because they didn't test the heater in a full home environment, so your theory isn't completely disproved yet... If they setup a normal home with a water heater like they did with full plumbing we might find faucets blowing instead of the heater itself... Hard to say, would be interesting to find out...