Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Disconnect grey wires (1) of 110°C high limit thermostat
on right hand side of boiler
Note:
The grey wires of the 110°C high limit thermostat are connected to two black wires (2) via male and female
spade connections
Disconnect grey wires (1) of 110°C high limit thermostat
on right hand side of boiler
Note:
The grey wires of the 110°C high limit thermostat are connected to two black wires (2) via male and female
spade connections
Measurement:
Measure resistance of 110°C high limit thermostat
(auto reset) across disconnected grey wires.
Reconnect wires after measurement.
(auto reset) across disconnected grey wires.
Reconnect wires after measurement.
Isolate as per TOPs P4
and refit as necessary