Set Appliance State:
Mains Power Off
Set Multimeter to Resistance 
Turn Hot Water Tap On
Boiler ON/OFF Switch OFF
CH Temperature Selector OFF
DHW Temperature Selector Max
CH Temperature Selector OFF
DHW Temperature Selector Max
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
It may be necessary to reduce flow rate at tap to assist temperature rise.
Allow Boiler to run and heat DHW to approximately 60 degrees C.
Turn Hot Tap OFF.
Disconnect yellow wire from DHW Sensor.
Measure resistance across the Sensor Terminals. Resistance should be
between 2-3 kOhms.
Reconnect wire after test.
Allow Boiler to run and heat DHW to approximately 60 degrees C.
Turn Hot Tap OFF.
| Isolate Mains Power to appliance as per TOP's P4 |
Measure resistance across the Sensor Terminals. Resistance should be
between 2-3 kOhms.
Reconnect wire after test.
Isolate as per TOPs P4
and refit as necessary