Air Conditioning - 2 Odd central A/C problems
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Radarrider
06-12-06, 02:11 PM
Just wondering if anyone can shed some light on 2 odd problems I have going on. I live in the Houston area and have a home that is about 2500 square feet, 2 story with one A/C unit.
Problem 1. Upstairs, my daughter's room a/c vent is blowing out 55 degree air. The room right next to my daughter's is the game room and it has two vents, both blowing out 75 degree air. I have had the coil cleaned and the filters changed etc. However, I can not understand how two vents that are both hard piped off of the plenum are putting out air that is 20 degree different.
Problem 2. Downstairs, our master bedroom and living room are next to each other and the amount of air going to the living room is 10 times more than the air going to the master bedroom and the 2 a/c vents in the master bathroom. My problem is that I need to get MORE air flowing to the bathroom and possibly the bedroom to get more cooling in there. I do not believe I have any shunts in any of the hard piped duct work. It was suggested to me that I could get a blower/fan and install it INSIDE the a/c vent to pull more cold air out but that seems kinda drastic.
Any ideas?
Problem 1. Upstairs, my daughter's room a/c vent is blowing out 55 degree air. The room right next to my daughter's is the game room and it has two vents, both blowing out 75 degree air. I have had the coil cleaned and the filters changed etc. However, I can not understand how two vents that are both hard piped off of the plenum are putting out air that is 20 degree different.
Problem 2. Downstairs, our master bedroom and living room are next to each other and the amount of air going to the living room is 10 times more than the air going to the master bedroom and the 2 a/c vents in the master bathroom. My problem is that I need to get MORE air flowing to the bathroom and possibly the bedroom to get more cooling in there. I do not believe I have any shunts in any of the hard piped duct work. It was suggested to me that I could get a blower/fan and install it INSIDE the a/c vent to pull more cold air out but that seems kinda drastic.
Any ideas?
timajul
06-12-06, 04:18 PM
Air travelling through a duct work system is like water draining through a field...it will choose the path of least resistance. In many parts of the county dampers are a code requirement for branch line ducts. I'm not sure about the Houston area, but if you have a basement, perhaps dampers could be retrofitted. This may allow you to "balance" the air flow, (limiting the flow to areas close to the supply fan, thereby increasing flow to an area farther away).
Another common problem is a lack of return air vents. Think of it like blowing up a paper bag, sooner or later the bag will be full and no more air can be forced into it. The same thing can happen to a room, (if the door is closed), and there is no return air vent, then it only has a limited capacity to accept additional airflow.
The temperature difference can also be explained by the path of least resistance analogy. Perhaps the branch line to your daughter's room is a direct line with minimal elbows while the game room branch duct could be restricted, (or partially disconnected somewhere), which could allow the air to become warmed by ambient conditions, (especially if the duct work is routed through an attic space).
Another common problem is a lack of return air vents. Think of it like blowing up a paper bag, sooner or later the bag will be full and no more air can be forced into it. The same thing can happen to a room, (if the door is closed), and there is no return air vent, then it only has a limited capacity to accept additional airflow.
The temperature difference can also be explained by the path of least resistance analogy. Perhaps the branch line to your daughter's room is a direct line with minimal elbows while the game room branch duct could be restricted, (or partially disconnected somewhere), which could allow the air to become warmed by ambient conditions, (especially if the duct work is routed through an attic space).