Inline duct fan & American standard furnace

gjack22911

I'm sure this question has been asked numerous times but here goes.

I have an American standard furnace and I'm trying to figure out how to hook up a sun court duct fan the smart way. I opened up the furnace and noticed there are 2 free terminals (EAC-N) and (HUM-N), after doing some research I purchased a relay but I'm stomped, I'm a single mom and can not afford to buy a new furnace so I'm looking for help on how to install the duct fan to get more heat to my sons room so he can start sleeping in his own bed again:)

Any help would be greatly appreciated.

hvacfreak2

There are a lot of relays out there , some more specifics on the one that you have would help out a great deal . Do you have the fan physically installed in the duct ? Sadly this can sometimes be a difficult job with marginal results.

If this is a current sensing relay it will clamp around the main fan power lead and close when the main fan is running. If this is a control relay you could energize it from w and c to run on a call for heat. The power supply will connect to one side of the contact and the fan to the other ( like a light switch ) . The fan will require a neutral as well. Make sure to cap unused leads . Good luck.

gjack22911

Hi I have a 24 volt general purpose fan relay, I didn't install the fan yet I wanted to test it and make sure it's runs before I install it. I was trying to get it setup for hot and cold.
So it wouldn't be smart to hook it up through the emc or hum?

hvacfreak2

I would check the unit diagram before connecting to those. EAC is usually 120 volt. If hum is 24 volts you could energize the relay from there.

JUGHNE

Is the EAC on anytime the fan runs (Heating or AC) & 120 VAC?

The Hum-N implies 120 VAC also but on in heating only?

What is the amp draw of your booster fan?

JUGHNE

Looking at typical furnace install book, one says the max HUM &EAC combined load to be 0.8 amps. (about 96 watts). And both are 120 volt outputs. Your furnace wiring diagram (on one of the doors) would have this info.
Assuming you have an AC T-stat you could turn the fan switch to "on". This will usually give you the highest blower speed available. See if you get heat at this speed. I don't believe a booster fan will deliver more air than that. IMO
A booster fan may not improve cool air movement much.

Air flow to a far room often is impeded because of lack of return air ducting to that area, the return of the air helps the pressurized supply air travel to that area. Sometimes leaving a door open will compensate for lack of return air in one room.

John Mills_5

Fan on usually gives you heat speed or lower. Both HUM & EAC terminals on American Standard are 120V. Need a relay with 120V coil. Furnace control energizes relay, relay powers booster. From my experience, you tend to get more noise than air from a lot of boosters.

captainco

You could get a very inexpensive fan control, Klixon or Thermodisc that bring the duct fan on anytime the plenum gets to 90 to 130 degrees. This way you don't have to worry about messing with any other controls on the furnace.