Hayward H300fdn IF code

[Johnnyduz]

Help!
I have a 4 year old Hayward H300fdn heater that starts and works normal for 30 minutes.
After 30 min it turns off and a IF code appears.
I read all the old posts. And tried almost everything. I cleaned the valves of any webs, bought new a heat sensor and a new ignitor sensor. I’m guessing it’s either the gas valve or the control board??? How can I tell which to change first?
Or could it be something else? Any help would be greatly appreciated!
Before I take a sledgehammer to it! Lol!!!

 

[ajw22]

Welcome to TFP.

Propane or NG?

Have you tested the gas pressures using a manometer? If so what are they?

If the heater shuts down with a IF it either lost gas pressure or it lost flame sense.

Have you checked examined the PCB for and creatures that crawled on it?

 

[Johnnyduz]

Welcome to TFP.

Propane or NG?

Have you tested the gas pressures using a manometer? If so what are they?

If the heater shuts down with a IF it either lost gas pressure or it lost flame sense.

Have you checked examined the PCB for and creatures that crawled on it?

It’s a NG heater.
I don’t have a manometer.
Might have to looking into getting one.
I checked the PCB (looks fine).

 

[ajw22]

Observe what happens to the gas pressure when the heater shuts down.