Problem with Atwood water heater

ScottG wrote:

Old-Biscuit wrote:

ScottG wrote:
Once a TPO spews hot water because of being over temp, it's shot because there's wax in it that melts. You have to replace it after fixing the root problem.

Where do you get this idea of 'wax' melting? It's not a fire sprinkler.

A T&P valve operates on 2 principles

1) High pressure (150#) overcomes spring pressure opening valve disc off seat and discharges water until pressure drops (125#). Drop in pressure is due to pressure being relieved thru T&P and the influx of cold water

2) High temperature (210*F). The probe is a thermostatic element that expands and lifts the valve disc off the seat relieving the overheated water which allows the influx of cold water. When the temperature cools below 210*F the thermostatic element will contract allowing the spring to close the valve disc against the seat.
And the T&P is ready to function again and again and again on high temp/high pressure situations.

You can (and should yearly) test the valve function by manually opening valve via lever and allow it to snap shut.

There is no wax that melts.

You are wrong on #2. There is wax in the section for temperature control (That's what expands) and it can and does fail completely. It is not designed to be triggered repeatedly. Link


Can you not discuss differing opinions without employing rudeness? Can you not offer another opinion and conduct yourself as a gentleman?

I misspoke.....
There is a wax fill inside the probe.

The wax doesn't melt and become unusable..it expands due to heat and then contracts when it cools. The wax is the means of the thermostatic element function. Can be used over and over and over.
T&Ps end up having to be replaced when spring tension weakens and/or valve disc/seat no longer seal.......not because they have operated.