My 670 sq foot two-story condominium has an evaporative cooler on the roof, a furnace in an upstairs closet (air intake at the base of the closet), an d a two-wire thermostat. There is no independent fan control. The evaporati ve cooler is ducted directly to the upper floor, without using the ducting that the furnace heating system uses in the winter. The cooler just dumps t he bulk of the cool air down the stairwell to the lower level. Opening an u pstairs window does not help much. I would like to run the furnace blower i n the summer time to help even out the cooling of my condo. I am not allowe d to go into the walls. The thermostat wire feels like it's stapled in plac e inside the walls, so I think there's no way I can wire up a three-wire th ermostat with an independent fan control. The furnace closet has an on-off switch for securing power to the furnace. For the summer time, is it okay t o disconnect the multi-colored wire bundle going to the furnace control boa rd and use the on-off switch in the furnace closet to turn on the blower as needed? The wires to which I am referring appear in the top middle of this photo:
I discovered this possibility this weekend. I had removed my furnace's blow er for cleaning. When re-installing the blower, I accidentally did not plug in the multi-colored wire bundle. The blower ran constantly without heat u ntil I figured out my mistake.
As an aside, in the three condos/houses I have owned over 20 years, I had n ever cleaned the furnace blowers. I did the taxes for an HVAC technician th e other week, as part of a community service gig. We were chattering about HVAC design as I did his taxes. He said cleaning the blower was some of the best major preventive maintenance one could do for a furnace. This weekend , I went at it. My condo's blower was filthy -- full of dust, dirt and fluf f. I took it outside, both vacuumed and blew it out with low-pressure air, sprayed Simple Green on the blades and wiped them, and used a lot of Q-Tips . Then I re-installed it. What a difference. The air the furnace blows is n ow odorless. There seems to be less dust in the condo, and I think it warms up more quickly.