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)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Boiler ON/OFF switch ON.
Measure the voltage across terminals marked
1 and 4 on the connection marked
ST13 on the PCB.
Note:
On older PCB's ST13 is a terminal strip,
on newer PCB's ST13 is just a row of
soldered connections however test
positions remain the same.
Measure the voltage across terminals marked
1 and 4 on the connection marked
ST13 on the PCB.
Note:
On older PCB's ST13 is a terminal strip,
on newer PCB's ST13 is just a row of
soldered connections however test
positions remain the same.
Isolate as per TOPs P4
and refit as necessary