Error Code h01 40: Return Air Overheat. The flue fan overheat switch has been detected as opened forcing the overheat cool down process to be initiated. So long as this switch remains open this fault condition is reported.
Brivis Error Code 40 Return Air Overheat: The flue fan overheat switch has been detected as opened forcing the overheat cool down process to be initiated. So long as this switch remains open this fault condition is reported.
For Heater Repair Tech Only
Reason: These errors will appear whilst an over temperature is current, the Over Heat Switch circuit is open, or the thermistor is measuring a temperature greater than 900 C. The heater’s fan will be forced to operate at maximum speed and the combustion fan will also be operating. All StarPro models have a supply air over heat switch located near the supply air discharge and is activated before the supply air reaches 90°C. This switch triggers at 110°C. StarPro SP 6 models are fitted with an additional over heat switch located in the combustion fan box to prevent the flue temperature exceeding 90°C. This switch triggers at 90°C. These switches directly interrupt the 24 Volt power to the gas valve if over heating occurs. If either or both over temperature switches open circuit indicating over temperature conditions within the Timed Safe Guard Period, then the following will occur during the over temperature condition: The power supply to the gas valve will be terminated. The fan will operate immediately, if not already operating. Once the over temperature condition has cleared and the switch resets, the normal heating cycle can commence again, provided the Networker is still calling for heat. The LCD will display “OHCooLDwn” for the next 60 seconds, alternating with the normal heating cycle displays i.e. HEAT= — — C0 . This is to indicate the heater has recently reset from an over temperature condition, but has now cooled sufficiently to resume operation:
If the Networker turns the call for heat OFF whilst the unit is in over temperature during a normal heating cycle, then after completing the “OHCOOLDWN” 60 second period the fan will then resume the normal CooLDOWN of the heating cycle. I.e. CoolDOWN as in the normal heat cycle according to the supply air outlet thermistor temperature. Service Check List: • Check the temperature registered at the nearest outlet to the heater, and compare this to the supply air thermistor temperature displayed on the NG-2 module. • Check the temperature rise value of the supply air thermistor and nearest outlet temperature, over the room temperature (Return Air intake temperature). A 470C. temperature rise will indicate a true overheat condition. • Check there are sufficient outlets open on the duct system. • Check the return air filter (if fitted) is sized correctly and is clean. • Check that the fan speed is sufficient for the system so that over heating will not result. • Check the fan motor is functioning correctly, and is not blocked or obstructed. • Check the ducting has not been crushed, damaged or incorrectly sized. • Check the return air intake is not subjected to a high temperature from an external source. • Check that the supply air thermistor is correctly fitted in the supply air duct. • Check the wire loom and plug connections to the switch are not open circuit, i.e. wire fallen off switch. • Check the supply air thermistor circuit is not shorted together or earthed. • Check the thermistor is not faulty, check that the resistance is approx 10 kΩ @ 20oC. • Check the link circuit on the NG-2 module between terminals 24 V. and STAT is open circuit.