Air Conditioning
I have just moved into a house about 40 years old. Very nice condition and was a good buy. There anyway to modify the fan motor so when heat or air is required will torque up to a higher RPM. I had this in my previous house and it was great. I admit I have not done too much research on the motor, so this question is just for feelers and help.
Answer:
The standard air flow rate is 400 CFM / ton for cooling and whatever the heating (furnace or resistive heat) manufacturer recommends for heating. Don't go messing with this unless you know what you are doing.Your question is a bit confusing. Most of us are assuming that you are asking if you can have two different fan speeds - one lower speed for heating and a higher speed for AC. If so, then the answer is "usually." Many fan motors have multiple taps for multiple speeds and it is pretty easy to determine how to change those taps IF you know what you are doing. If not, then get some advice from somebody who has done this many times or integrate this simple modification with a routine service call for HVAC maintenance. The pro shouldn't charge you too much extra to "rewire" the motor as long as he is already out to your home for the annual maintenance call. Also, many tract home developments built around 40 years ago had the same furnace, AC and ductwork in most of the homes. If you locate a neighbor with the same setup as yours, then you can check out which taps are being used on his fan. This isn't 100% guaranteed, but it is usually safe. Many of us could make a good educated guess on which taps and fan speeds should be used, but I'm not going to make that blind suggestion over a newsgroup. Final comment: Be certain that whoever pulls out that fan/blower assembly cleans the squirrel cage if needed and lubes the motor. Fins on the squirrel cage can get clogged with dust, especially if the home has every had an electronic air filter which was neglected. Also, some motors are difficult to lube and some HVAC guys skip one or both oil ports on the motor.