Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Gain access to PCB (use Insulation Mat as required)
Disconnect plug from diverter motor and make safe
Disconnect plug from diverter motor and make safe
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Test 1:
Press the reset button on the front of the appliance and while the boiler runs its start-up sequence measure the dc voltage between pin 7 and a suitable earth.
Expect voltage to fluctuate between 0V DC, 12V DC and 22V DC before settling on 0V DC after approximately 5 seconds.
Repeat test on pin 8.
Test 2:
Press the reset button on the front of the appliance and while the boiler runs its start up sequence measure the dc voltage between pin 15 and a suitable earth.
Expect voltage to fluctuate between 0V DC, 12V DC and 22V DC before settling on 22V DC after approximately 5 seconds.
Repeat test on pin 16.
Press the reset button on the front of the appliance and while the boiler runs its start-up sequence measure the dc voltage between pin 7 and a suitable earth.
Expect voltage to fluctuate between 0V DC, 12V DC and 22V DC before settling on 0V DC after approximately 5 seconds.
Repeat test on pin 8.
Test 2:
Press the reset button on the front of the appliance and while the boiler runs its start up sequence measure the dc voltage between pin 15 and a suitable earth.
Expect voltage to fluctuate between 0V DC, 12V DC and 22V DC before settling on 22V DC after approximately 5 seconds.
Repeat test on pin 16.
Isolate as per TOPs P4
and refit as necessary