HVAC interfacing


Hey all,

I'm gettin ready to put my first order into hobby boards!

I know that x10 etc can interface with HVAC thermostats, however, i was wondering if there were any 1-wire methods?

I know there is a kit at hobby boards to monitor the hvac system, but how about driving it?

Aprilaire, HAI, and RCS are widely used. Each one may have one or more of the following interfaces : RS-232, RS-485, Zwave, or X10.

Never seen a 1 wire Thermostat.

depends on what type of system you have . . . most HVAC control is 24vac and controlled via relays . . . but most fans/pumps need more than the 3amp rating of the hobby-boards 4 Channel Relay module . . . you could you this module to drive higher rated relays to switch the fans/pumps in your set-up though . . .

. . . but this leaves you no 'easy control point' other than via the computer . . .

Pete C

I love my country, but fear my government.
The HAI omnistat rc-122 two stage programmable thermostat looks like the way to go. Its not 1-wire but does program over a rs-232 port and can interface with misterhouse (i think).

After googling around I found some documentation on building your own, but that's perhaps a little risky...