RESISTANCE RETURN TEMPERATURE PROBE

Isolate Mains Power to appliance as per TOPs P4

Set Multimeter to Resistance

Remove the side panel
Remove the leads from the return temperature probe (blue leads)

Measure the resistance between the exposed
terminals on the return temperature probe.

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.

Note.
If you can't remove or partially remove the side panel you will need to remove the temperature probe to carry out this test.