Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove the connector X401 from the control box
Measurement:
Measure resistance across the blue wires at the right hand side of the plug.
RESISTANCE SENSOR FLUE OVERHEAT AND HARNESS
| Temperature Range (°C) | Resistance Range |
|---|---|
| 0°C to 10°C | 33.5kΩ - 48.0kΩ |
| 10°C to 20°C | 23.6kΩ - 33.5kΩ |
| 20°C to 30°C | 17.0kΩ - 23.6kΩ |
| 30°C to 40°C | 12.5kΩ - 17.0kΩ |
| 40°C to 50°C | 9.4kΩ - 12.5kΩ |
| 50°C to 60°C | 7.2kΩ - 9.4kΩ |
| 60°C to 70°C | 5.5kΩ - 7.2kΩ |
| 70°C to 80°C | 4.4kΩ - 5.5kΩ |
| 80°C to 90°C | 3.5kΩ - 4.5kΩ |
| 90°C to 100°C | 2.8kΩ - 3.5kΩ |
Resistances vary with temperature and should conform approximately to the table below:
Note: Clicking on the resistance table will switch between table and graph view.
Isolate as per TOPs P4
and refit as necessary