Raypak heater won't stay on

[Pcmaker]

I have a Raypak heater that's around 7 years old.

It wont stay on. The ignitor would ingite the burner and it just shuts off. No error codes.

I jumped the pressure switch, the high limit switch, the flame roll out fuse and I replaced the ignitor with a brand new one. The flame looks nice and blue then it shuts off. What else could it be? Could it be a bad temperature sensor? Bad board? I have good water flow through the heat exchanger.

 

[Pcmaker]

Ok, now the flame is yellow. What does this mean?

 

[ps0303]

If the unit lights and then goes out it's highly likely the board.

 

[danpik]

How quickly after it lights does it shut off?

 

[Pcmaker]

Under 10 seconds

 

[danpik]

Check for a wire probe sticking into the pilot flame (I assume this has a pilot), that is the flame sensor. It needs to be cleaned. Steel wool will take care of it. Also check the wire coming out of it and see what the connection on the board looks like. Should be clean with no corrosion.

 

[ps0303]

Which model Raypak is it?

If you already replaced the ignitor, which is also the flame sensor, then I still am leaning towards the board.

 

[danpik]

Good point Paul. I missed the part where he said he replaced the igniter.

 

[Pcmaker]

Yeah, it's a brand spanking new ignitor.

Could be the board like you said. How about the gas valve? Does it have anything to do with it shutting off after a few seconds? I also haven't cleaned the orifices on the burners, I don't think that's got anything to do with it, though.

 

[ps0303]

The board controls what's happening. So the system lights, then the signal goes back to the board to tell it that its lit. If that signal doesn't get back to the board or the board just doesn't see, the system shuts down. The gas valve is a dumb part and only does what its told to do by the board. Sort of like a marriage. LOL just kidding.....

 

[Pcmaker]

What about the yellow flame? Is that normal?

 

[danpik]

Is the flame rolling out the front of the unit? Yellow is not good and may indicate a plugged up flue/heat exchanger.