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Tammy HallJul 28, 2025
What does error code A1 mean on a Hayward HDF400 Gas Heater?
- XxgarzaJul 28, 2025
If your Hayward Gas Heater shows the 'A1' error code, this indicates the switch circuit never closed when the blower turned on, or it re-opened within 10 seconds of the blower starting.