Two-story house on full basement with zoned AC units (located in basement and attic). Downstairs AC has never been a problem, but last two summers the upstairs AC has had problems (leak in brazed line 2 summers ago and kicker cap last summer).
Upstairs is the master bedroom/bath, jack & jill bath shared by two bedrooms (one converted to a mini home theater and the other to my study), and a 4th bedroom with its own bath. The Home theater was off all day yesterday, but the two PCs were on for part of the day.
Ok, I get up yesterday morning and its 74ºF upstairs because this is where the wife set the thermostat. I do the yard work between 945AM and 1145AM and come in. While catching my breadth, I turn on my PCs upstairs and set the thermostat to 73ºF. I like it cool, because I am a Yankee.
30-45 minutes later I’ve caught my breadth and decide to get cleaned up. I set the thermostat down to 72ºF (it had reached 73ºF by now) and hop into the shower. By the time I get out of the shower the thermostat is ready 74ºF (it went up) while its still set to 72ºF. Okay …
I go out and run my errands (groceries = grillable meats, beer, etc.). Ok, its now like 3PM and its still 74ºF upstairs with the thermostat set to 72ºF. I give up and shut everything off (which was only the two PCs) upstairs and go downstairs. BTW, downstairs the thermostat is set to and reading 74ºF and its cooler.
I stay downstairs because it is cooler, but I notice that at 8PM there is no change upstairs. I could care less because I am about to play some X-Box Live (Ghost Recon) with the guys, which means plenty of beer with all the shooting. But what irks is an alcohol thermometer my wife brought home read 29ºC, which is 84ºF and this is what it read at 1AM when I got done playing games!
Yesterday’s recorded high for my zipcode was 88ºF (93ºF Heat Index). Either the upstairs zone is having a problem, the heat load of the attic itself is making a warm impression on the second floor environment, or a combination of both. The ridge-peak in the attic is 18′ high with no firm place to put a ladder (moonscape uneven surface with blown fiberglass) so the DIY attic vent-fan idea is lost.
I am going to stick that alcohol thermometer up in the attic today and at 4PM take a reading. If it reaches 120ºF when 88ºF outside then a +30º loading is probably the problem. AC conduits are those round flex tubes. Its all FUBAR in the attic and not welcoming to anything less than a true monkey. Guess I can call a HVAC tomorrow and see what it costs for them to install one or two attic ridge fans.
Replies
So what'd you find out?
Nothing yet. When I last called my fave HVAC company they were busier than alley cats in the storm drain behind my house. Can't say that I blame them for being busy, but a working HVAC system (to them) is a low-priority.
I'll give them another call this week. I also have got to call the electric company and have them install a whole-house surge-protector. Last Thursday the f-ing lightning in and around Atlanta is taking its toll on my home electronics. Everyday for the past 2.5 weeks we have thundershowers where the lightning is downright mean (lost a monitor and video card).
And now I am out of LP and Brats sitting there saying, "grill me." Where's lightning when you need it?
Does the AC come on when you lower the temperature 2 degrees? Maybe the tolerance is larger than you think, or maybe the thermostat is bad. I had a couple of hunter programmable thermostats that went bad on me, and this is the type of behavior they exhibited (on heating though).
I think its just the way the builder and or HVAC installer designed the system, which is MB first and everything else last. I also noticed that there is no return in the master closer, water closet, or rest of the master bath. This means the master suite has four source vents and one return, but that return seems dang small (same size as the rest of the bedrooms which have one source vent).