F4
AstralPool
Limit String Open (Safety Chain Open)
Heater displays F4; may occur immediately after start command.
Advertisements
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.
Advertisements
Possible Causes
Open high limit thermostat, Open flue temperature switch, Open water pressure switch, Loose wiring in safety circuit
How to Fix / Troubleshooting
Safety first: Turn off power. Do not bypass safety switches for operation.
- Inspect safety wiring harness: Follow the low-voltage safety loop wiring from the control board through each limit switch. Look for loose or disconnected spade terminals.
- Check manual reset limits: Some AstralPool models have manual reset high limits or flue stats. Press the reset button if present after the heater has cooled.
- Check for overheating causes: If a limit has tripped, verify water flow and flue ventilation before resetting.
If F4 remains, individual safety switches should be tested with a meter and replaced if open when they should be closed.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
AstralPool High Limit Thermostat
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements