Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Gain access to PCB (use Insulation Mat as required)
Selector switch to DHW position
CH temperature selector to minimum
DHW temperature selector to maximum
Selector switch to DHW position
CH temperature selector to minimum
DHW temperature selector to maximum
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Allow fan to run and burner to ignite.
Measure the voltage across the modulating solenoid terminals. Approximately 8-10 volts should be present.
Measure the voltage across the modulating solenoid terminals. Approximately 8-10 volts should be present.
Isolate as per TOPs P4
and refit as necessary