AboutJim Barnhart Expertise Fifty + years in Heating, Ventilating, Air Conditioning, Sheet Metal Manufacturing.
Semi retired since 1995,
Experience Answer questions about , residential and commercial.
Answer questions about sheet metal fabrication.
Fifty years plus experience.
No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances.
I have a Ruud A/C Heat pump with gas backup installed in the attic of my home in Williamsburg VA. The problem is that the blower seems to operate independently of the tstat at times. Here is the scenario: the A/C operates just fine overnight and shuts off based on the tstat program. When the A/C shuts off the blower stops. Some time later in the morning, with no changes to the controls on the tstat, the blower starts on its own with no A/C operating and no indication on the tstat that the blower is running. In the evening, the A/C comes on and the cycle repeats the following day. This has occurred with the original Ruud manual tstat, a replacement Hunter tstat that didn't work otherwise and the current Honeywell tstat which is working fine.
Answer Terry,
Your blower is controlled by a blower relay in your air handler/furnace, the thermostat mode/setting directs the power to start the blower for use with cooling, with heating or just plain manually on.
You could have a shorted thermostat wire, your blower relay could be faulty, some blower fan switches are activated by heat.
Depending on what your attic unit is and how old it is, it sounds like heat from the attic is activating your blower on switch, It may be adjustable?
