Posting this hoping it'll help save someone else from a similar headache.
Opened the pool this year and the heater (Pentair MasterTemp 400) wouldn't ignite. Blinking "Pool Heating" light for ~30 seconds, click, smelled gas outside, no light. Heater tried this three times and the "Service Heater" light came on.
Okay, we smell gas out the exhaust so it's probably a bad igniter. Replaced the igniter. Same result.
Shut off the gas, removed the igniter from the combustion chamber, tried again. Definitely glowing red hot, so we knew it wasn't a bad igniter.
Even though we smelled gas, I began to suspect the gas pressure was for some reason incorrect. Hooked up a manometer in line before the heater and tried again. Pressure was 8" WC, but dropped straight to zero as soon as the gas solenoid in the heater clicked open. Bingo!
Went outside and looked at the gas pressure regulator and, sure enough, the holes on the vent limiter were clogged. Cleaned 'em out, and the heater started right up. Problem solved!
Problem was the two little holes inside the brass vent cover in the middle of the picture above were clogged with dirt, probably a mud dauber nest or something. The original igniter probably wasn't even bad. We also had a mechanical company come out and look at it, and the tech was convinced the igniter was the wrong one because it didn't extend far enough past the insulation into the combustion chamber. He didn't even check the gas. But the fix was stupid simple the whole time.
If your heater won't ignite, it might be this, might be something else. But at least check the vent on your gas pressure regulator before you do anything more involved or pay someone to come look at it for you. If you don't have a limiting device on there, it's even more susceptible to this.
Opened the pool this year and the heater (Pentair MasterTemp 400) wouldn't ignite. Blinking "Pool Heating" light for ~30 seconds, click, smelled gas outside, no light. Heater tried this three times and the "Service Heater" light came on.
Okay, we smell gas out the exhaust so it's probably a bad igniter. Replaced the igniter. Same result.
Shut off the gas, removed the igniter from the combustion chamber, tried again. Definitely glowing red hot, so we knew it wasn't a bad igniter.
Even though we smelled gas, I began to suspect the gas pressure was for some reason incorrect. Hooked up a manometer in line before the heater and tried again. Pressure was 8" WC, but dropped straight to zero as soon as the gas solenoid in the heater clicked open. Bingo!
Went outside and looked at the gas pressure regulator and, sure enough, the holes on the vent limiter were clogged. Cleaned 'em out, and the heater started right up. Problem solved!
Problem was the two little holes inside the brass vent cover in the middle of the picture above were clogged with dirt, probably a mud dauber nest or something. The original igniter probably wasn't even bad. We also had a mechanical company come out and look at it, and the tech was convinced the igniter was the wrong one because it didn't extend far enough past the insulation into the combustion chamber. He didn't even check the gas. But the fix was stupid simple the whole time.
If your heater won't ignite, it might be this, might be something else. But at least check the vent on your gas pressure regulator before you do anything more involved or pay someone to come look at it for you. If you don't have a limiting device on there, it's even more susceptible to this.
