Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
DHW Demand
Disconnect the 2 wire plug from the programmer
Use insulation mat as required
Use insulation mat as required
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the resistance at the two exposed pins on the programmer.
Resistance should be short circuit (zero resistance).
Resistance should be short circuit (zero resistance).
Isolate as per TOPs P4
and refit as necessary