Jacuzzi pool heater starts normally but shuts off when the pump speed is reduced (variable-speed pump systems).

Safety first: Turn off power to the heater before adjusting internal switches; pump programming can be done with power on.

Steps to correct low-flow shutdowns:

• Review pump programming: Increase the minimum RPM during heating cycles to meet Jacuzzi’s required flow rate.
• Adjust bypass valves: Reduce bypass flow so more water passes through the heater, but do not fully close a manufacturer-required bypass.
• Check pressure/flow switch: Some switches are adjustable; a qualified technician can fine-tune the setting so the heater remains on at normal low-speed flow.