Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Remove black plastic covers from the back of the Control Box
Remove connector from X502 from control board
ON/OFF Switch in ON Position
Mode Selector Switch in Hot water position
Remove connector from X502 from control board
ON/OFF Switch in ON Position
Mode Selector Switch in Hot water position
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Test 1:
Check for approximately -24 Volts DC at link W25 on Control board and terminal marked N on the Main Switchboard terminal strip.
Test 2:
Check for approximately -24 Volts DC at connector S (black lead) on Control board and terminal marked N on the Main Switchboard terminal strip.
Note.
Voltages measured will be negative.
Check for approximately -24 Volts DC at link W25 on Control board and terminal marked N on the Main Switchboard terminal strip.
Test 2:
Check for approximately -24 Volts DC at connector S (black lead) on Control board and terminal marked N on the Main Switchboard terminal strip.
Note.
Voltages measured will be negative.
Isolate as per TOPs P4
and refit as necessary