What CHECK FLOW means
The heater isn't seeing enough water pressure: the pump isn't running, pump pressure is low, the pressure switch has a fault, or a variable-speed pump is set too low.
Likely causes
- Pump off or too slow
- Dirty filter or full baskets
- Closed valves
- Missing return eyeball fittings
Safe first checks
- Make sure the pump is on and, if variable speed, at a high enough speed.
- Turn the pump off at the breaker, clean the filter and baskets (release pressure first), open the valves, and make sure the return eyeball fittings are in place.
When to stop
If flow is good and it stays, have a qualified tech check the pressure switch. Never bypass it.
Parts that may help
Only order a part once the checks above point to it, and match the part number to your model.
Checked against: Jandy JXi gas-fired pool and spa heater installation and operation manual (H0574300). Codes can differ by model and year, so confirm with your owner's manual.
