Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove leads to flow thermistor
If required attach temperature clamp to the flow pipe
to determine temperature range

Measurement:

Measure for resistance across the exposed pins of the flow thermistor.
The resistance depends on temperature and should
conform to the table below:
Flow Temperature °CResistance in kOhms
10 - 2019.0 - 12.0
20 - 3012.0 - 8.0
30 - 408.0 - 5.0
40 - 505.0- 3.8
50 - 603.8 - 2.5
60 - 702.5 - 1.7
70 - 801.7 - 1.3