Fig. 130. Checking the thermostat"s functionality
To check the thermostat's functionality, tie a piece of wire to it and lower it into a container filled with water (Fig. 130). Lower the thermometer in the same way. Make sure that the thermostat and thermometer do not touch the bottom or walls of the container.
Heat the water gradually and use a thermometer to determine at what temperature the thermostat opens.
The thermostat should begin to open at 85–89°C. At 100°C it should be fully open.
After checking, place the thermostat (still hanging by the wire) in cold water and see if it closes within 30 seconds.