Hi everyone, I need help on finding the right booster fan for my application. I know for a fact that you must already have a bad opinion at that point but hopefully I can explain why I think that this time, it just might help with my situation.
Initially the ductwork was made for a basic central system, that I finally replaced with a carrier greenspeed due to the insulation and airtightness of the house (long story short, everything is awesome and cost of operation is great)
only thing I now had as a problem is that it wasn’t efficient to climate the whole house down to 17C during summer when I only needed the 3 rooms of the 2nd floor at that temperature.
I managed to make modifications to the ducts and added a zoning system.
Now my problem : the second story bedroom vents (2 per room, 1x5’’+1x6’’, 6totals) run from the the mech room with lots of elbows. my new zoning duct is 14x8 or something like that and managed to connect the bedrooms to it.
anyhow, even with a good zoning damper as close as possible and everything full open and optimized as it can be with that setup, I require a high cfm from the carrier system to be able
to push air at night.
Now, the real problem I have is that there are 3 returns on the 2nd floor, one per bedroom, and there is a 18x18 register on the bottom of the the staircases (open/modern stairs) and there are two 12x12 opening on the intake side of the furnace. I had one cutout initially, but had to add a second one as it required a lot of return air when running full speed and there is just too much elbows, turns and duct lenghts on the returns of the 2nd story that the machine was cavitating without it.
Now you see where I am getting at! sorry if this was a long journey… So my problem now is that I can have sufficient AC in the bedrooms, its comfortable and such, but if I leave the doors open it will never be able to cool and the whole house will be cooled down for nothing. If I close all the bedroom doors before night cooling, there is a lot, i mean a lot of air exiting underneath the door, which is sucked all the way down through the house by the basement mech room 18x18 register. So again, the whole house goes down to 17C at night even if the damper/zoning shoots all
the air to the 3 bedrooms with the doors closed. Even on 22-25C nights we sometimes go down for breakfast and its 16C so we start the gas fireplace. (Sometimes I wake up for work earlier like 4:30am and I still want to keep the bedroom at 17 until girlfriend wakes up, and makes no sense to cycle from heating/cooling when its 25 outside).
So what I am looking for would be to add a booster fan on the return air from the bedroom. The three return ducts are joined togeter in a 8inch duct in the mech room. (just a reminder, these are the only returns ducts I have, the main returns is two 12x12 cutouts on the side of the vertical duct prior to the filter that feed from the 18x18 opening in the mech room wall at the bottom of the staircase)
Ideally, I could have a 8 inch booster fan running on that return duct at low speed when the system is working, but it would kick in fast speed when the system has the damper set to shoot air only for the bedrooms.
Note that right now, a kleenex does hold in place in front of the return vents in the bedrooms, but if I blow on it sideways it falls.
Or just a booster that doesn’t turn unless zone 2 becomes priority and then starts. I can wire any of those scenarios easy (i think), its a matter of knowing if such fans exist, are they energy efficient, and what do you guys think?
Thank you very much for your time and your help,
Sent from my iPhone using Tapatalk
Initially the ductwork was made for a basic central system, that I finally replaced with a carrier greenspeed due to the insulation and airtightness of the house (long story short, everything is awesome and cost of operation is great)
only thing I now had as a problem is that it wasn’t efficient to climate the whole house down to 17C during summer when I only needed the 3 rooms of the 2nd floor at that temperature.
I managed to make modifications to the ducts and added a zoning system.
Now my problem : the second story bedroom vents (2 per room, 1x5’’+1x6’’, 6totals) run from the the mech room with lots of elbows. my new zoning duct is 14x8 or something like that and managed to connect the bedrooms to it.
anyhow, even with a good zoning damper as close as possible and everything full open and optimized as it can be with that setup, I require a high cfm from the carrier system to be able
to push air at night.
Now, the real problem I have is that there are 3 returns on the 2nd floor, one per bedroom, and there is a 18x18 register on the bottom of the the staircases (open/modern stairs) and there are two 12x12 opening on the intake side of the furnace. I had one cutout initially, but had to add a second one as it required a lot of return air when running full speed and there is just too much elbows, turns and duct lenghts on the returns of the 2nd story that the machine was cavitating without it.
Now you see where I am getting at! sorry if this was a long journey… So my problem now is that I can have sufficient AC in the bedrooms, its comfortable and such, but if I leave the doors open it will never be able to cool and the whole house will be cooled down for nothing. If I close all the bedroom doors before night cooling, there is a lot, i mean a lot of air exiting underneath the door, which is sucked all the way down through the house by the basement mech room 18x18 register. So again, the whole house goes down to 17C at night even if the damper/zoning shoots all
the air to the 3 bedrooms with the doors closed. Even on 22-25C nights we sometimes go down for breakfast and its 16C so we start the gas fireplace. (Sometimes I wake up for work earlier like 4:30am and I still want to keep the bedroom at 17 until girlfriend wakes up, and makes no sense to cycle from heating/cooling when its 25 outside).
So what I am looking for would be to add a booster fan on the return air from the bedroom. The three return ducts are joined togeter in a 8inch duct in the mech room. (just a reminder, these are the only returns ducts I have, the main returns is two 12x12 cutouts on the side of the vertical duct prior to the filter that feed from the 18x18 opening in the mech room wall at the bottom of the staircase)
Ideally, I could have a 8 inch booster fan running on that return duct at low speed when the system is working, but it would kick in fast speed when the system has the damper set to shoot air only for the bedrooms.
Note that right now, a kleenex does hold in place in front of the return vents in the bedrooms, but if I blow on it sideways it falls.
Or just a booster that doesn’t turn unless zone 2 becomes priority and then starts. I can wire any of those scenarios easy (i think), its a matter of knowing if such fans exist, are they energy efficient, and what do you guys think?
Thank you very much for your time and your help,
Sent from my iPhone using Tapatalk
source https://hvac-talk.com/vbb/threads/2241614-Booster-fan-question-sorry-)?goto=newpost
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