James, I was hoping you can help me as well. Similar situation.
H400 Gas Heater about 10 years old. Just opened pool.
Turned heater on and set temp to call for heat.
I can hear blower, I see the "heat" light illuminate then it clicks and fails.
That cycle repeats two more times, then IF code.
I checked both the supply gas line is open and the gas control module is set to on inside the unit.
I included a picture here. I check the four fuses, all look good. I use a meter to check the igniter. It read 14 ohms.
I guess I have a newer style one? you can see it at the bottom of the picture. Any advice on next steps?
I have no idea how to check the gas pressure or regulator, and don't think I smell any during these cycles.

H400 Gas Heater about 10 years old. Just opened pool.
Turned heater on and set temp to call for heat.
I can hear blower, I see the "heat" light illuminate then it clicks and fails.
That cycle repeats two more times, then IF code.
I checked both the supply gas line is open and the gas control module is set to on inside the unit.
I included a picture here. I check the four fuses, all look good. I use a meter to check the igniter. It read 14 ohms.
I guess I have a newer style one? you can see it at the bottom of the picture. Any advice on next steps?
I have no idea how to check the gas pressure or regulator, and don't think I smell any during these cycles.
