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Tami HernandezAug 17, 2025
What to do if my Hayward H400FDP shows 'Ignition Failure'?
- LLori MartinezAug 17, 2025
If your Hayward Heater is experiencing ignition failure, you should inspect the ignition system for faults.
What to do if my Hayward H400FDP shows 'Ignition Failure'?
If your Hayward Heater is experiencing ignition failure, you should inspect the ignition system for faults.
What to do if my Hayward Heater displays a 'Communication Error Between Control Module and Display Interface Assembly'?
If your Hayward Heater shows a communication error between the control module and the display interface assembly, verify the connections between these components.
What to do if my Hayward Heater displays 'Temperature Sensor (thermistor) input failure'?
If your Hayward Heater shows a 'Temperature Sensor (thermistor) input failure', check the temperature sensor and replace it if necessary.
What to do if my Hayward Heater shows 'Ignitor Circuit Open'?
If your Hayward Heater displays 'Ignitor Circuit Open', check the ignitor circuit for continuity.
What to do if my Hayward H400FDP Heater indicates 'Keypad failure'?
If your Hayward Heater indicates a 'Keypad failure', the solution is to replace the keypad.
What to do if my Hayward H400FDP Heater displays 'Maximum return water temperature exceeded and / or rapid water temperature rise'?
If your Hayward Heater displays 'Maximum return water temperature exceeded and / or rapid water temperature rise', check the water temperature sensors and system settings.
What to do if my Hayward H400FDP shows 'Flame present with Gas Valve not energized'?
If your Hayward Heater shows 'Flame present with Gas Valve not energized', check the gas valve and ignition system.
What to do if my Hayward Heater displays 'Voltage polarity reversed, low voltage detected'?
If your Hayward Heater displays 'Voltage polarity reversed, low voltage detected', correct the polarity and ensure proper voltage is supplied.
What to do if my Hayward Heater shows 'Water Pressure Switch, Vent Pressure Switch, or Temperature Limit Switch Fault'?
If your Hayward Heater indicates 'Water Pressure Switch, Vent Pressure Switch, or Temperature Limit Switch Fault', inspect all associated switches for proper operation.
What to do if my Hayward Heater displays 'Blower Vacuum Switch open'?
If your Hayward Heater displays 'Blower Vacuum Switch open', inspect the blower vacuum switch for faults.
Describes the normal heating cycle sequence.
Details the sequence for when the heater fails to ignite.
Details electrical and control connection points for the heater.
Details electrical and control connection points for the heater.
Step-by-step guide to place the heater in bypass mode.
Guide to setting temperature lock-out features on the heater.
Instructions for measuring and adjusting gas pressure for proper operation.
Lists and defines diagnostic error codes for troubleshooting.
Lists part numbers for common replacement parts used in troubleshooting.
Troubleshooting steps for when the heater does not power on.
Troubleshooting guide for open FC1 or F2 fuses.
Troubleshooting guide for the 'LO' diagnostic code.
Details minimum and maximum water flow rates for the heat exchanger.
Provides instructions on how to inspect the heat exchanger for damage.
Illustrates common failure causes for heat exchangers.
Presents a schematic diagram of the heater's internal wiring.
Illustrates the overall wiring connection diagram of the heater.
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