I would like to convert(hack/mod) a digital thermostat into a temperature controller. Most of it is fairly straight forward, extend the thermistor and hook up a relay to the appropriate hvac coded circuits to control the dependent circuit.
Most (all) digital thermostats (for homes) take 24VAC from the hvac system for power.
24VAC relays are expensive ($15); 24VDC relays are cheap($4).
Is there any reason I can't (shouldn't) simply supply the thermostat with 24VDC instead of 24VAC?
Thanks, Matt