Raypak 406a Digital ignition trouble

[robpiat]

I've got a 406a digital nat gas heater. Its 3 years old.

All of a sudden it will not come on. I pulled the panel, checked the ground, and it goes through an ignition sequence. The pilot comes on, lights, and it appears the pilot flame sensor is not relaying. After a period, the display shows Ignition Failure.

The gas never fully rolls on. I don't see a part or wire for a flame sensor. How do I differentiate if I need to replace the pilot assembly, control board, or gas valve?

 

[Texas Splash]

Still working that issue? Just in case, I'm going to poke @Pool Clown for some help. Next time he's online maybe he can give you some pointers. Thanks for posting.

 

[Pool Clown]

The ignition cable and ground are whats used for the flame sensor. A good ground at the pilot AND at the transformer are crucial. Also remove and inspect the pilot assembly and make sure there is no corrosion or soot that could impact the flame sensing routine.