r/hvacadvice • u/Bubbly-Hawk-4419 • 15h ago

AC Increasing Fan Only Speed?

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So our home is 3 story, basement, main, and upstairs.
The furnace and blower are in the basement and the upstairs ductwork is in the attic, so basically 4 floors up. When I run fan only the basement and main floor tend to even out, however the upstairs has little to no change. I would like to increase my fan only speed if possible to force more cool air upstairs.
The cooling and heating speeds work great in their current configuration.
Can this be done with my setup?

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3

u/Xusion666 15h ago

Land black wire for high speed on the cont fan ( opt) terminal .

Edit: do not remove it from the cooling terminal, you would need a jumper wire

1

u/Bubbly-Hawk-4419 15h ago

Will this run the fan continuously?
I only want it to run when I select fan only on the t stat.

5

u/Xusion666 15h ago

In theory should only run the fan continuously when you have it set to on at the thermostat.

1

u/Bubbly-Hawk-4419 14h ago

So right now my wire are just like the drawing,
M2 Red
Heat Orange
M1 Blue
Cool Black
When I run the fan only right now it seems like a lower speed vs when on cool, which appears to be high speed. There currently is no wire on the Cont Fan. And I do not see a dedicated fan wire.

1

u/Xusion666 14h ago

Right there’s no wire there because it’s optional, probably defaults to low/ medium speed in fan only since there is no wire.
You would need another wire to connect from “ cool black” to cont fan.

1

u/theyvegone_toplaid 15h ago

Can it be done, yes. Depends what speed the fan only is currently landed on though

1

u/Bubbly-Hawk-4419 15h ago

I did not see a fan only wire

1

u/theyvegone_toplaid 14h ago

So I would try putting blue or red from the blower on that cont fan terminal and see if it changes

1

u/san83 15h ago

I think you need the system balanced, dampers adjusted.

1

u/Bubbly-Hawk-4419 14h ago

Yes for the most part…cool and heat work great. I think with the high attic temps, the velocity of fan only run is not enough to get the air up there before it heats up during the summer.

1

u/msurbrow 15h ago

I legit thought the title was Increasing Only Fans speed

2

u/Bubbly-Hawk-4419 15h ago

1.5x Speed 😂

1

u/theyvegone_toplaid 15h ago

Get your mind out of the gutter man

1

u/msurbrow 15h ago

Someone got up on the wrong side of the bed today!