So I finally got the relay card (Midon design 1WIO) and everything else set up. Just as a reminder I'm running the HVAC wires from the thermostat (instead of one wire in each screw in the thermostat coming from my AC system I have it also go to my relay card). The red wire (24VAC) goes directly to my relay card, bypassing the thermostat, and the blue one (unused in my system) is hooked up to the red screw for the thermostat. This way, when I want to allow thermostat control I have a relay that connects the blue and red wires, otherwise blue is left unconnected and the thermostat is off.
Now I thought everything was working, but because it has been rather cool lately I have noticed some weird behavior:
1. When the thermostat is set to AC, I can turn on both AC or heat using the relay card (at least I assume the heat is heat as it takes 3 minutes to come on and nothing else does after being shorted).
2. When the thermostat is set to heat, I can turn on the heat _but not the AC!_ In other words when AC is shorted to 24VAC nothing happens _only when the thermostat is set to heat_. Since I am just passing the AC connection basically directly (both the wire from the AC unit and the wire to my relay card tie into the screw on the thermostat, which I would imagine should just conduct any current and/or voltage) I am having a hard time seeing how this is possible, unless I am just completely missing something???
Any help would be appreciate with this dilemma. I'm stumped for the moment at least.
EDIT: Ok so apparently this is a fan issue as my fan is controlled by the thermostat but for some reason for both heat & cool in AC mode and only for heat in heat mode. I wired up another relay to the green cable. For AC its easy just turn on fan when AC turn on, turn off when AC turns off. For heat I know there is a delay in turning on and off; I can just mimick this delay with timing but is there any better method?
2ND EDIT: Ok never mind seems I only need to control the fan for AC which is easy (on for AC, off when turn off). Anyhow now I am using all 4 of my SPDT switches (1 for AC/heat, 1 for fan, 2 to either send 24VAC to tstat or myself but to make sure that this never happens in the power off NC connected state or the power on but no 1Wire which is NO).
Thanks
Misha
