Column 8
Handy fix-it folk take note. Lenore McCotter, of Springwood, has ”noticed in the latest catalogue to lob into my mail box that on Sunday, February 28 Bunnings will hold a DIY workshop, ‘How to install a leaking tap’. Unfortunately there doesn’t appear to be a follow-up workshop on how to fix it.”
Read more on Sydney Morning Herald
We moved into a new home three years ago and we have had a consistent problem with the upstairs cooling system. The home is two stories and approx 3100 sq/ft. There are two heating and cooling units, one for each floor. The first floor unit is in the basement and the second floor unit is in the attic. We have two compressors outside, a 2.5 ton for the first floor and a 3 ton for the second floor.
The first floor cooling works great. No issues.
The second floor system does not keep up. If we set the thermostat at 76 and it gets into the 90s outside, the upstairs temperature will rise to 82/83 degrees.
We have had several contractors come out to look at it and the main consensus seems to be lack of return air flow and inefficient design of the ductwork in the attic (many long runs of 6″ flexduct going in every direction.
The system has two supply trunks and one return trunk. Double the number of supply lines compared to return lines.
My question is, can I cut into the return trunk and add a couple of return air lines? There is room for two more lines or so. I will add registers at opposite end of the upstairs hallway.
I may also rearrange some of the existing flexduct lines to make the runs shorter (esp the supply runs) although I will make sure not replace supply runs with return runs and vice versa.
Any advice regarding whether this project on my part would make sense would be greatly appreciated. I am somewhat handy but definitely a novice with respect to HVAC issues.
Adding return will not be a negative to the system. As far as the supply runs, I always look at a ten percent loss when using flex and size up one inch larger diameter on average runs. If they are indeed long runs a 6 inch solid pipe would be figured as an 8 inch flex. Sounds like your system wasn’t properly sized from the get-go.
Old Lennox unit — Outside compressor unit – fan doesn’t run -fan housing is very hot – but spins freely and will begin running if you push start it by hand (either direction in fact). Compressor is not running either (both run off same capacitor)- but getting hot also. Any thoughts as to whether or not I’m possibly correct?
Likely the capacitor indeed. Do you happen to have a capacitor tester handy?
The capacitor you have may be a dual unit (3 terminals). Check the size, it should read something like this: 25-5 MFD, 470VAC or some other printed information. Buy an identical replacement (same MFD and VAC numbers). Be careful to mark the wires so they go to same terminals with the new capacitor.
The compressor is hot and apparently not running (at least when you were around looking at it) b/c an internal safety called the “overload protector” is preventing it from burning up and dying in front of your eyes. So turn the A.C. OFF before you lose your compre$$or.