Cooling Question (A/C Fan Speeds)?

Question

I have an aireflow blower/furnace unit currently being used for cooling. its hard to keep the house consistantly cool, as it is large with 2 floors. i was wondering if theres a way to set this particular model to run constantly in a low fan mode (consuming less energy when the compressors arent on. The model number is AF90MPE100U4B and it is a 4 year old AireFlow model. there are no visible selectors in the unit suggesting that this can be done with a quick flick of a switch. Thanks for any info in advance. il post any updates if you need more info. Eric.

Answer 1

"Former" is correct. You need to add a relay to provide this function. They do it all the time for people with electronic air cleaners they want to run 24/7.

But even in the slow speed, although much quieter, it is still a little bit of white noise all the time.

Answer 2

Ther is no way of doing this without addin any extra relays. I could explain how to add a 24 volt relay to run your fan at low speed and have it switch to high speed when the air comes on, but it would serve you just as good to go ahead and just run the fan at high speed even though the air isn't on. Your air circulation would be much better for what you are trying to achive. And the extra cost on electric will not be that much.

Answer 3

Some thermostats have an "auto" or "on" selection for the fan. You might check that. The "auto" selection turns the fan on only when heat or cooling is on. The "on" selection will leave the fan on continuously.

Answer 4

to my knowledge all, (never say all), indoor fan motors run at about 700 cfm for central air in ac mode. this is high speed for blower motors. gas and other forms of heat run at low/medium speed, including heat pumps, (i think it's about 400 cfm). i think electric heat runs at the same 700 cfm, but i may be mistaken on that. if i am, e- heat is low or medium speed for the blower motor as well.

typically, the indoor blower motor is hard wired for the correct specifications. they do make some really sophistcated efficient motors now that switch speeds depending on the heat load on structure.

you have to remember, it has to do with air flow across your coil, and simply increasing or decresing cfm of the motor will not make unit more efficient. in fact, it will cripple efficiency! hope this helps.

un, if you own this property, you should consider a load calculation and possibly a new efficient unit with zone heating and cooilng and possibly better insulation. but lowering the blower speed and laeving the outdoor fan and compressor on longer is not a solution. bet that!

i guesss you could make it where when the outside unit cut off, your indoor fan would stay on and switch to low speed, but i'd just use ceiling or box fans for all a that.

Answer 5

HVAC Tech.: The amount of electricity a motor uses is based on its voltage and amp draw, not its speed.Whether it runs fast, medium, or slow it uses the same amount of electric. The voltage and amp load don't change. As it is required that the air be turned over 10 times an hour in a given space, that is what determines the size and speed of your blower. Hope that helps you understand.