Posts Tagged ‘ Fired ’

Have moved into a house where previous owner replaced simple mechanical type thermostat (with mercury bulb) with an electronic unit. Mechanical type obviously just closes a contact to complete the gas valve circuit and so get 24V across gas valve coil.
Obviously 2 wire electronic unit cannot do this because the unit needs to draw power for the electronics.
The new thermostat is giving unreliable operation, am thinking of replacing it with the old unit which I found and appears to be functional (checked with multimeter).