Velocity of airflow central air vs my furnace


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Old 05-31-17, 01:40 PM
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Velocity of airflow central air vs my furnace

Hi all,

I just had a new Amana 3 ton 14 Seer central air unit installed. I live in Northern Michigan, so it really hasn't got even close to hot enough to test the unit properly. I have run it though, and Ive noticed that the velocity of the air coming out is much lower than the velocity when I run the furnace. Is this normal?
 
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Old 05-31-17, 07:11 PM
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Are you referring to airflow in cool mode or with the Fan switched to the On position?

If you refer to Cool mode airflow then I would verify that the Y wire from the condenser and the Y wire from the thermostat are connected to the furnace Y terminal. ( this may not apply to some air handlers with electric heat)

Back in the 80's gas furnaces ran the same fan speed for Fan or Cool. This changed in the early 90's but many old timers do not know this fact. They just connect the condenser Y wire to the thermostat Y wire using a wire nut, bypassing the furnace. This will result in very poor airflow in the cool mode.

But..
If you are referring to low air flow when only running the Fan in the On position, this is normal.
 
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Old 06-01-17, 04:57 AM
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Cool mode vs Heat mode

I was referring to cool mode vs heat mode. Much more velocity coming out of the ducts on heat mode. So it sounds like this is not normal? It will be 80 degrees here on Saturday, so I will get a chance to test out the system this weekend and see how effectively it cools the house down. If it doesn't I will b calling them back and I will mention the Y connection thing.

Or I may try and figure out how to connect the Y wire to the furnace terminal myself if I can figure that out lol
 
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Old 06-01-17, 05:34 AM
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There is a possibility that you have a greater load on the system in heat mode than cool mode.
This is never the case in my neck of the woods.

Northern Michigan probably runs much colder than anything that I see in Texas.
 
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Old 06-01-17, 04:23 PM
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I did verify that the Y connections from the condenser and the thermostat are both connected to the furnace Y terminal. Maybe its all in my head, but it sure does seem like heat mode blows through the ducts at a much higher velocity than cool mode.

Its supposed to be close to 80 degrees here on Saturday. I guess all I can do is wait till then and see how effectively the ac unit cools the house.
 
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Old 06-01-17, 04:36 PM
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I had a new high efficiency furnace with a variable speed blower installed in 2008. With my old furnace, the blower speed was the same in heat or cool mode. With the new furnace, the blower speed in heat mode (once it's ramped up to max speed) is very high. It sounds like a mini hurricane blowing out of the vents. In cool mode, the air velocity is noticeably lower. I would guess that the blower speed in cool mode is ~1/2 that of heat mode.
 
 

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