How Does A 2 Wire 24 Volt Ac Electronic Thermostat Work To Control A Gas Fired Furnace ?

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).

Tags: Control, Electronic, Fired, Furnace, Thermostat, Volt, Wire, Work

This entry was posted on November 16, 2009 at 6:30 am and is filed under Thermostats. You can follow any responses to this entry through the RSS 2.0 feed.