Set Appliance State:
Mains Power Off
Set Multimeter to AC Volts 
Water heater switch set to constant
Set thermostat to MID position
Set thermostat to MID position
Gas On
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Allow burner to ignite, system to run and reach set temperature.
Does thermostat operate when temperature is reached?
To detect operation of thermostat measure the voltage across connection 4 (blue lead) and connection 24 (yellow lead) on the control module.
Note.
Before operation voltage will be present,
after operation no voltage will be present.
Does thermostat operate when temperature is reached?
To detect operation of thermostat measure the voltage across connection 4 (blue lead) and connection 24 (yellow lead) on the control module.
Note.
Before operation voltage will be present,
after operation no voltage will be present.
Isolate as per TOPs P4
and refit as necessary