RESISTANCE DHW SENSOR AND HARNESS

Isolate Mains Power to appliance as per TOPs P4

Set Multimeter to Resistance

Disconnect connector from ST9 on the PCB
If available use the Worcester test PCB to assist resistance test

Measure resistance across pins 17 and 18 (Yellow) leads at the disconnected connector ST9.

Harness lead colours may differ, however the test points will remain the same.

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.