THERMISTOR FLOW TEMPERATURE OVERHEAT

Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4

Set Multimeter to Resistance

Disconnect the low voltage Molex connector from the PCB

Measurement:

Measure resistance across the red wires of the connector.
Note:
Boiler will go to overheat lockout if the thermistor resistance goes below approx. 700 Ohms.

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Temperature Range (°C)	Resistance Range
0°C to 10°C	20.0kΩ - 32.0kΩ
10°C to 20°C	12.0kΩ - 20.0kΩ
20°C to 30°C	8.1kΩ - 12.0kΩ
30°C to 40°C	5.4kΩ - 8.1kΩ
40°C to 50°C	3.7kΩ - 5.4kΩ
50°C to 60°C	2.6kΩ - 3.7kΩ
60°C to 70°C	1.9kΩ - 2.6kΩ
70°C to 80°C	1.4kΩ - 1.9kΩ
80°C to 90°C	1.0kΩ - 1.4kΩ
90°C to 100°C	800Ω - 1.0kΩ

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.