"mcsteve" wrote in message
...
Hello all...

I have an on-demand gas fired water heater. It is an Aquastar, model
# AQ 125-B. Recently, it has been leaking through what I believe to be a
drain
valve. When I run the hot water, the valve spews and won't shut off. I
have to
shut down the supply line and after I wait a bit it will cease leaking.
I want to know the purpose of this valve, and why it's 'acting up' in
this
manner.

Photo of valve: http://i37.tinypic.com/s41hrm.jpg

Photo of heater: http://i34.tinypic.com/30t1a43.jpg

The valve is mounted about 12" below the heater. Unit
is a wall mount. Valve is at the end of a horizontal cross
member that's 'teed' off the vertical pipe that I assume is
the outlet from the heater.

Hoping I can fix this myself. I've done my share of soldering
pipe in the past. This fitting appears to be glued, rather than soldered.
It is threaded.
I don't want to call a plumber.


TIA
--
Steve M

That's a pressure relief valve, it blows off on high temperature or
pressure. Either a control in the unit is allowing the temperature or water
pressure to rise beyond what it should, and the valve is just doing what
it's there for, or the valve has gone bad. The valve screws on to the
fitting and appears to have some type of dope or sealant on it. There is
also a possibility that the building water pressure is to high feeding into
the heater