Controller displays FRZ or FREEZE and forces circulation through the Heliocol panels even when heating is off.

Safety first: Be cautious of icy, slippery surfaces around the pool and on the roof. Turn off power before adjusting sensors.

• Confirm ambient conditions: Check actual outdoor temperature. If it is near freezing, the FRZ indication may be normal operation to protect the Heliocol panels.
• Inspect freeze sensor: Locate the freeze/air sensor, usually near the equipment pad. Ensure it is not mounted in a location that gets colder than the general area (e.g., against metal or in a draft).
• Check wiring: Tighten freeze sensor terminals at the controller and inspect the cable for damage.
• Adjust freeze setpoint: If allowed by the controller, set the freeze protection temperature to the manufacturer-recommended value to avoid nuisance activation.
• Replace sensor if faulty: If the sensor reads freezing temperatures when the actual temperature is much higher, replace the freeze sensor.