Water Heater Eruption

[mb576]

It erupted through the relief valve. Only place it can right? What could be the causes and how to prevent this again. Gas heat, temperature set at one less than scalding. Four settings below this. I turned it back by one anyway, just in case. Boiler is less than a year if that has anything to do with it. Please help. Its -10 with wind chill here in conn.

[Pilot Dane]

That valve can open (erupt) for two reasons. Either the water in the tank is too hot or there is too much pressure. Like anything, the valve can go bad but they tend to be quite reliable. You could replace the T&P valve since they are pretty inexpensive.

How hot is the water coming out of the heater? Have you changed anything recently (water heater temp. setting, water pressure...)?

[mb576]

Yes. I turned up the heat setting a couple of months ago, and since the eruption lowered it.