Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect the yellow leads from primary sensor
Measurement:
Measure resistance across the exposed sensor terminals.
RESISTANCE SENSOR TEMP FLOW
Resistances vary with temperature and should conform approximately to the table below:
| Temperature Range (°C) | Resistance Range |
|---|---|
| 0°C to 10°C | 1.80MΩ - 3.30MΩ |
| 10°C to 20°C | 1.10MΩ - 1.80MΩ |
| 20°C to 30°C | 660.0kΩ - 1.10MΩ |
| 30°C to 40°C | 420.0kΩ - 660.0kΩ |
| 40°C to 50°C | 270.0kΩ - 420.0kΩ |
| 50°C to 60°C | 180.0kΩ - 270.0kΩ |
| 60°C to 70°C | 120.0kΩ - 180.0kΩ |
| 70°C to 80°C | 85.0kΩ - 120.0kΩ |
| 80°C to 90°C | 60.0kΩ - 85.0kΩ |
| 90°C to 100°C | 45.0kΩ - 60.0kΩ |
Note: Clicking on the resistance table will switch between table and graph view.
Auto Range may show resistance in Mega(M) or Kilo(k) ohms e.g. 750kΩ = 0.750MΩ
Isolate as per TOPs P4
and refit as necessary