4.8 Frost protection FROST PROTECTION To prevent freezing the appliance is equipped with an internal frost protection. If the heat exchanger temperature falls too low, the burner switches on and the pump runs until the heat exchanger temperature is sufficient. When the appliance frost protection is activated the symbol code 7 is displayed (pre heating the heat exchanger). If the installation (or a part of it) is in danger of freezing, an (external) frost thermostat must be fitted to the return line at the coldest location. This must be connected in accordance with the wiring diagram (See § 8.3).
Note If the appliance is out of operation ( - on the service display) the appliances internal frost protection is still active. However, this means there will be no response to a request for heat from an (external) frost thermostat. Intergas Heating Ltd 15