Water Heaters - Residential Hot Water heater on the fritz

10 year old Ruud PVP50-1 not igniting. Vent fan turns on, ceramic coil gets hot, but gas valve is not opening when it should. Problem is intermittent. I have had limited succes (I know this is stupid, but it works more often than not) with taking a wooden handle and smacking the control assy or the thermostat housing. I cannot find schematic for controller anywhere online and I'm about ready to shotgun board if parts are available (unless someone can identify a part that is most likely to die over time). Otherwise I'm out $140 + shipping for a new controller.

That said, is there any way the thermostat could be keeping the gas valve from opening?

Background: I've changed out all the spade lugs to the controller, diaphram and gas valve. The system does occassionally function normally for short periods of time (hours to maybe a couple of days)before it gets hung up again.

I make a point not to work on these PowerVent water heaters because of the numerous issues, brands, models to cover the parts with.

I along with numerous other master plumbers farm this type of work out to a fellow who can afford to keep that type of inventory on the truck and have the call demand to support the inventory needed to make the repairs.


I will say that thermostats do go bad, and I do offer myself to those replacements...but I need confirmation of that task before I go working on those units, otherwise I'm not going to waste my time or the customers.

It's a great body of thinking but I don't have the call volume to support the move.