Display shows Er4 or ERR4 and ozone or auxiliary devices do not operate
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.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power at the GFCI breaker before working on accessory circuits.
Er4/ERR4 indicates a fault on an auxiliary output such as ozone.
- Inspect ozone generator: Locate the American Whirlpool ozone unit and check for water intrusion, burnt smell, or melted housing.
- Disconnect accessory: Temporarily unplug the ozone generator or accessory from the control pack, then restore power to see if Er4 clears.
- Check wiring: Ensure accessory wiring matches the spa's wiring diagram and that no wires are shorted to ground.
If Er4 clears with the accessory disconnected, replace the ozone generator or faulty accessory. If it persists, the control board auxiliary relay may need replacement.
Repair Difficulty
Required Part
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