281 Issue 1 - Service Manual - BX3
21
•
The gas valve has failed to open and has Detected as failure
•
Gas valve drive relay contacts fail to close
•
Short open or half wave
•
Gas valve drive triac fault
Service Check List:
1. Check the gas valve wiring has not been disconnected.
2. Check that there is no break in the wiring loom.
3. Check that the gas valve has not shorted or is in open circuit.
4. Check voltage to the wiring loom to gas valve.
5. Check the control board if board failure.
5.8 Seven Flashes – Over Temp Lockout
Reason
Too many overheats activations in latest heat cycle
Overheat activation continues longer than overheat fan and cool down
Service Check List:
Please refer to overheat conditions in this manual.
5.9 Eight Flashes – Frequency Lockout
Reason
•
Supply frequency outside operating limits
•
Microprocessor clock outside operating limits
The frequency check determines that the operating frequency of the micro-controller internal
clock is correct. Comparison against the known mains frequency signal, being 24v AC 50Hz,
shall be used to make this determination. The duration of this test shall be approximately 0.5
seconds A failure in the clock circuit shall enter the unit into lockout and flash the eight flash on
the LED status light.
Service Checklist
1. Check power supply.
2. Check polarity at power point.
3. Check transformer voltage.
4. Control board failure.
