Hayward HDF400 Pool Heater Error Codes A1 and A2

[Beyer6505]

Good morning all,

Went to kick on the heater today and it turned on, but didn't fire up and isn't heating. At that time it was giving an error code of A1. I turned it off, flipped the breaker, and let it sit for an hour before trying it again--same thing. It turns on, I can hear the gas start flowing but the ignition isn't firing and it doesn't heat. Again, error code A1.

I went into the manual and of all the codes listed, A1 isn't one. So I pulled up an old thread here on TFP and went through the steps suggested of removing the cover and checking the electrical and hose connections to ensure everything was properly seated.

After doing that, we flipped the breaker again and tried turning it on. With the cover off, I tried blocking the Combustion Blower at the Natural Gas Fuel/Air mixer with my hand and the A1 code went away but an A2 code came up. If I held my hand their longer and it tried to light but would just cycle again and again. The A2 code isn't listed on Hayward's diagnostic list.

I've sent an email to Hayward though I'm not sure they're open weekends. The four Hayward tech options in our area also aren't open weekends. The other TFP thread suggested it may be the differential pressure switch, but am wondering if anyone else has experienced this and if so, what your fix ended up being?

Thanks in advance for any ideas or guidance!

ETA:

 

[Texas Splash]

Hello and welcome! You made this post about a week ago but haven't received a reply. Still need help?

 

[h2oskibilly]

Good morning all,

Went to kick on the heater today and it turned on, but didn't fire up and isn't heating. At that time it was giving an error code of A1. I turned it off, flipped the breaker, and let it sit for an hour before trying it again--same thing. It turns on, I can hear the gas start flowing but the ignition isn't firing and it doesn't heat. Again, error code A1.

I went into the manual and of all the codes listed, A1 isn't one. So I pulled up an old thread here on TFP and went through the steps suggested of removing the cover and checking the electrical and hose connections to ensure everything was properly seated.

After doing that, we flipped the breaker again and tried turning it on. With the cover off, I tried blocking the Combustion Blower at the Natural Gas Fuel/Air mixer with my hand and the A1 code went away but an A2 code came up. If I held my hand their longer and it tried to light but would just cycle again and again. The A2 code isn't listed on Hayward's diagnostic list.

I've sent an email to Hayward though I'm not sure they're open weekends. The four Hayward tech options in our area also aren't open weekends. The other TFP thread suggested it may be the differential pressure switch, but am wondering if anyone else has experienced this and if so, what your fix ended up being?

Thanks in advance for any ideas or guidance!

ETA:

I have the same issue!! I’m monitoring your thread for resolution

 

[swamprat69]

Hayward is always FUN to troubleshoot as it is difficult to find the exact manual for different models with the included parts list with parts numbers. Photos of the air pressure switch and its label along with photos of the blower motor and its label might be helpful. Better yet would be the actual installation and service manual for the specific model. The obvious "A" code errors could be due to a number of causes and troubleshooting the root cause would involve using a manometer to check the setpoint of the air switch against actual pressure that the air switch is seeing and then tracing the cause if the pressure that the switch is seeing is marginal.