AO4
Jandy
Air Flow Fault – Pressure Switch State Error
Heater displays AO4 and will not start heating cycle.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Pressure switch stuck closed, Incorrectly adjusted pressure switch, Shorted pressure switch wiring, Control board sensing error
How to Fix / Troubleshooting
Safety first: Disconnect power before testing switches.
- Check switch state: With the heater off and blower not running, the air pressure switch should be open. If it shows continuity, it is stuck or misadjusted and should be replaced.
- Inspect wiring: Look for pinched or shorted wires between the pressure switch and control board.
- Verify tubing routing: Ensure the tubing is connected to the correct port on the blower housing and not cross-connected with other lines.
- If AO4 continues: The control board input circuit may be faulty and require replacement by a technician.
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Repair Difficulty
Hard
4/5
Required Part
Air Pressure Switch
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