Carrier bryant furnace blower high speed only

Are you saying that it will only run on high speed, or that you want to set it up to run only on high?

We just moved into this older cottage. The controller and motor were replaced in 1995. The motor (appears to be a 4-speed) runs fast (and very noisy) all the time. Motor has white (C), black (1), yellow (2), blue (3) and red (4) wires. The controller board (model # HH84A021) connects to the motor with white to white, black to black and red to yellow. It is a heat only setup with 2-wire thermostat wires connected to the R and W terminals on the controller board. In heat mode 'W' it's supposed to run on the low speed. I looks like from the schematic that the red wire is connected to the low speed contact of the Hi/Low relay. I have tried moving the red wire from the controller board to the red wire on the motor but it has little if any effect.

Yes, red wire on the blower motor is low, but there isn't a whole lot of difference between low and med, so you may not be able to notice the difference by ear. Some blowers are just noisy, especially if the return grill is very near the furnace.

If that's the case then whoever installed this furnace in this cottage did not do their job. I would say an 80,000 BTU furnace for 720 sq. ft. is grossly oversized. My previous home was more then double the size of this cottage and ony had a 70,000 BTU furnace. Considering the size of this place, maybe a lower speed motor would have been more appropriate. No big deal, we're leaving for Florida Jan 2nd and won't be back till the end of May or early June. We plan on replacing it then with a new heat/air unit. In my opinion whomever installed the present equiptment in 1985 was not interested in the comfort level of its occupants. In this place ALL of the grills are near the furnace. When the furnace comes on and the drapes and window blinds go bananas and you have to turn up the volume of the TV to hear it, it's an indication someone didn't do their job right!

You may very well be correct. There are a lot of hacks out there. However, its hard to say if the previous owner mentioned adding on in the future, and asked the installer to oversize accordingly. Just never know. Anybodys guess. Good luck with everything. Merry Christmas and Happy New Year.

Thank you for your input and Merry Christmas and Happy New Year to you.