Valliant Gas Water Heater MAG 325/7ATZW

by Thompson Curtis
(Waterbury, CT)

I have a Valliant wall mounted 3390 MAG325 natural gas hot water heater. The main burner will not stay lit. It lights up when temperature control is turned most of the way to the left (counterclockwise), stays lit for 30 seconds ...then the whole unit shuts down including the pilot light. What might be the problem? Any suggestions are most welcome!

The unit has a new diaphragm in place. Could this problem have to do with the thermocouple or the thermoelectric magnet?