Thread: Self contained ceiling air conditioner

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2. If it's not ductless it must be setup for ducts. Do they want you to run multiple supply ducts to the same room? I say if the all the supplies and returns are balanced properly anf the coil sees the same CFM and the fan motor the same static pressure it will work. Balancing a such a simple system should be a piece of cake.

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The manufacturer is saying that this unit should not be connected to multiple rooms as unbalanced air flow may occur creating positive or negative pressure in the room. But I am trying to find a way to convince them that you can connect the unit to multiple rooms as long as you have equal amount of CFM going into the room and coming back from the room to the unit from both the rooms.
They are against it big time.

4. Originally Posted by Samart
The manufacturer is saying that this unit should not be connected to multiple rooms as unbalanced air flow may occur creating positive or negative pressure in the room. But I am trying to find a way to convince them that you can connect the unit to multiple rooms as long as you have equal amount of CFM going into the room and coming back from the room to the unit from both the rooms.
They are against it big time.
Yes, I know, I've read the whole thread. Which EXACT unit is it? Are you a homeowner or an installer/technician? Are you trying to put this in your own home?

5. Originally Posted by dlove
you cant be negative in a room that doesn't have enough air supplying it. It only becomes negative if your returning more than what your supplying.
Isn't that what my math was showing? 267 CFM Supply minus 800 CFM Return equals -533 CFM.... therefore more return than supply equals negative pressure.

Samart: I don't think there is enough external static pressure for your AC. 0.15 inches is pretty low and some of the take-offs from trunks can add 30+ ft to the effective length of the duct (check Manual D for exact effective lengths).

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Based on the feedback received from everyone so far, is it safe to say that there will be no problem as long as there's balanced airflow -enough CFM going in to the rooms and same cfm coming back to the unit? I mean if it is done based on the maximum external static pressure, CFM of the evaporator fan and appropriate length of the ducts.

Please let me know how many of you agree with it and how many of you disagree with it.
Thank you

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Thread relocated to "Tech to Tech"

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9. Originally Posted by hcong
Isn't that what my math was showing? 267 CFM Supply minus 800 CFM Return equals -533 CFM.... therefore more return than supply equals negative pressure.

Samart: I don't think there is enough external static pressure for your AC. 0.15 inches is pretty low and some of the take-offs from trunks can add 30+ ft to the effective length of the duct (check Manual D for exact effective lengths).
I stand corrected

BYW there is no such thing as negative PRESSURE. You can only have one at a time.

10. Originally Posted by BURL-REF
10 to 1 its a Movincool

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