Set Appliance State:
Mains Power Off
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Boiler Thermal Store must NOT be at maximum temperature, otherwise the Cold Start Thermostat will operate and prevent the measurement of the Normally Closed Contacts. To achieve this, run off some Hot Water.
Boiler Thermal Store must NOT be at maximum temperature, otherwise the Cold Start Thermostat will operate and prevent the measurement of the Normally Closed Contacts. To achieve this, run off some Hot Water.
Measurement:
Measure a Short Circuit resistance between Connection 9
(on the 12 way Terminal Block) and Connection 2
(Brown - on the rear of the Cold Start Thermostat).
Note:
This test can only be performed on appliances with THREE WIRE COLD START Thermostats.
Some early appliances were fitted with two wire 'Clickson' type Thermostats
(fitted at low level, L/H side of the Thermal Store).
If a two wire Thermostat is fitted select the "Short circuit" option below.
(on the 12 way Terminal Block) and Connection 2
(Brown - on the rear of the Cold Start Thermostat).
Note:
This test can only be performed on appliances with THREE WIRE COLD START Thermostats.
Some early appliances were fitted with two wire 'Clickson' type Thermostats
(fitted at low level, L/H side of the Thermal Store).
If a two wire Thermostat is fitted select the "Short circuit" option below.
