What Does This Error Mean?

Chromagen frost protection works by circulating warm tank water through the collector when temperatures drop near 3°C. If the controller is off or the pump has failed, frost protection will not activate — pipes on the roof can freeze and burst overnight in cold climates.

Affected Models

Chromagen STD series (frost-protected)
Chromagen TS series (frost-protected)
Chromagen Soltherm
All Chromagen systems with frost protection

Common Causes

Controller powered off — frost protection requires the controller to be on 24 hours a day including overnight
Circulation pump failed — frost protection pump cannot run without a working pump
Frost protection temperature threshold set too low — factory default is 3°C, some regions need 5°C
Thermistor sensor fault — controller cannot detect low collector temperature without an accurate sensor
No frost protection at all — thermosyphon (passive) Chromagen systems do not have electric frost protection

How to Fix It

Leave the controller powered on at all times.

Chromagen electronic frost protection requires the controller to be powered on 24/7 — including overnight and in winter. Do not switch off the controller circuit breaker at night or during cold weather. If the controller display is blank, the frost protection function is inactive and the system is at risk.
Check the frost protection setting in the controller.

Access the Chromagen controller menu (hold the SET button for 3 seconds) and navigate to the frost protection temperature setting (labeled FP or FROST). The factory default is usually 3°C — in areas with hard frosts, increase this to 5°C or 7°C. The controller activates the circulation pump when the collector sensor reads below this threshold.
Verify the circulation pump is working.

When frost protection is triggered, the circulation pump runs to move warm water from the tank through the collector pipes to prevent freezing. Listen for the pump running on a cold night — a soft hum or flow noise from the pipes near the tank is normal. If the pump makes no sound or shows a fault on the controller, the pump has likely failed and needs replacement.
Drain the collector if pipes are already frozen.

If the system is frozen and not producing hot water, do not try to force flow — cracked pipes may be holding pressure. Allow the system to thaw naturally during the day. After thawing, inspect all collector pipe connections and the collector itself for splits or cracks before running water through the system again.
Consider pipe insulation for extreme cold climates.

In regions with regular hard frosts (below -5°C), foam pipe insulation on the roof-mounted collector connections provides an additional layer of protection. Insulate the exposed inlet and outlet pipes to the collector with high-temperature outdoor-rated foam lagging. For very cold climates, a Chromagen-authorised installer can also add glycol to a closed-loop system as permanent freeze protection.

When to Call a Professional

Frozen and burst collector pipes require a plumber and possibly a solar technician. Prevent further damage by turning off the water supply to the unit. After thawing, have the system inspected before resuming use.