Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Remove DC connector from pump.
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Reset boiler, wait 10 seconds after power is reinstated, press and
hold reset button for 5 seconds, then release.
Measure the voltage across 3rd terminal (white wire) from top of ST18 and
DC neutral terminal as illustrated.
Voltage should be seen to drop after 10 seconds from boiler reset, then
rise to 5 VDC after 30 seconds from boiler reset (times and voltages are approximate).
Note :
To repeat test, press and hold reset button for 5 seconds then release.
hold reset button for 5 seconds, then release.
Measure the voltage across 3rd terminal (white wire) from top of ST18 and
DC neutral terminal as illustrated.
Voltage should be seen to drop after 10 seconds from boiler reset, then
rise to 5 VDC after 30 seconds from boiler reset (times and voltages are approximate).
Note :
To repeat test, press and hold reset button for 5 seconds then release.
Isolate as per TOPs P4
and refit as necessary