I’ve had my Hayward HD100ID1 for 5 years now. Sadly, I have gotten very familiar with the schematics and have self-serviced this many times. This time, I am stumped!

The heater will run for about 10 minutes (up to an hour once) and then the gas shuts off way before reaching temperature. The fan blower is still running and but the gas valve is closed. Per the schematic, this can only be a couple things:

I did all of the following with no success (gas valve still shuts off and blower still runs):

• Jumped the two temperature sensors
• Jumped the air flow sensor
• Cleaned and replaced the flame sensor

Any other sensor in the system would cause the whole system to shut down, including the blower?

One odd thing, I do notice the blower fan is running "faster than normal" and the gas valve won't open again after restart until the whole heater cools down? Could it be a bad gas valve? If this is the case I wouldn’t expect it to open at all?

I replaced the control board a year ago, this one has a red LED that blinks 3 times consecutively, then pauses, and blinks 3 times again when the system shuts down. However, I can’t find anything about the LED codes.

I would love any suggestions you may have to try next… Please!

 

Welcome to the forums.

That appears to be a newer replacement board and since the older one didn't have fault codes.... they aren't listed in the service manual. Your board should have come with a manual describing the faults. I'd need the part number from that board to comment further on fault codes.

Those heaters have/had two major problems.... the board and the gas valve. It looks the board may have been upgraded and I'm seeing a 120v to 24v transformer for the gas valve which means they no longer use the 120v valve.

Service manual (pdf)

 

Thanks @PJmax. I ended up replacing the gas valve. Going to have a warm pool for the remaining months of summer/fall! Thanks!

 

Good job. Thanks for letting us know how you made out.