Second thermostat trouble!

[Firewoodjoe]

I have a OWB and I installed a second thermostat to kick on only the blower to my gas furnace. That way everything was hooked up and workable year round. Propan, A/C and wood boiler. Well I had a furnace guy come and change the blower in the propan furnace last year. He screwed the wiring up and couldn't get all three to work. So I had him leave the A/C off. I've been trying to hook it up like I had it and no matter what I do when the second stat. turns on it turns my A/C unit on! What did he do! I just pulled the breaker to te Ac.

[r.man]

Normally there are thermostat connections for heat, cool, fan, and possibly others depending on the unit. Sounds like you are turning on the a/c instead of fan only. With the outer unit breaker off it would act just like fan only. Your a/c terminal should be attached to the appropriate coloured wire on the main stat.