Hayward 400 IO Failure code

[torchroadster]

I have a 10 year old Hayward 400,000 BTU Propane heater. Yesterday it gave me an IO (ignitor open) failure code and wouldn't fire up. Pulling the ignitor connector and measured the resistance at 15 ohms which is in the middle of the good range. Wiring looks good. That's where the Hayward troubleshooting manual stops.

Any ideas?

One note - the screws on the flame sensor are completely rusted off and the flame sensor is hanging in it's mounting hole. Although not good it doesn't seem that should create this error.

Thanks for the help

 

[ps0303]

What is the exact model of the unit? If the flame sensor screws are rusted off, I wonder what the condition of the rest of the insides look like.

 

[torchroadster]

The model number is H400FDP.

The rest of the inside of the heater looks good. At least everything behind the side panel that exposes the the blower and control boards. It seems the flame sensor screws didn't have a corrosion resistant finish

 

[ps0303]

Yes the manuals stops there as they are thinking that the ignitor will not test in the good range. All I can suggest it try a new ignitor and hopefully that is it and the reading you got was incorrect.

You could call Hayward support and see if there is any other testing they can tell you about. Other then the ignitor it could be the integrated control board of which the ignitor is plugged into.

 

[Hayward Pool]

Since the flame sensor is rusted and the connection is not good there may be a poor ground. Replace the flame sensor and if it does not solve the problem check all the wiring for the ignitor. If the wiring is ok, replace the ignitor at that point. As always we strongly recommend that this be done by a heater technician.

 

[torchroadster]

Reporting back on the resolution of this problem:

First there is no ground on the flame sensor so the rust is a non-issue from an electrical standpoint. The ignitor tested good out of the circuit so I saw no reason to replace it.

I removed the control board and close inspection found an open trace on a ground return path. I repaired the trace by soldering a wire between two vias in the printed circuit board at either end of the open trace. After reassembly the heater passed all self tests and fired up normally. I've now run it three different times over the past two weeks for extended periods and all seems fine. I was somewhat worried because I couldn't identify the root cause of the open trace, but perhaps it was animal or insect related since I did find evidence of both under the cover.

Thank you for all the advice and tips.

 

[ps0303]

Would seem off that a rodents scratched the board. The board is mounted so close to the firewall it would be a magical feet for something to get behind it. But I guess stranger things have happened.

Glad you found the issue and resolved it. Happy heating!