If you've been having this trouble since it was installed, you should have had your contractor check it.
Have you changed your air filter lately.
Water around outdoor unit.
There's water around the outside unit. I don't see it freezing up and a repair guy just charged it with coolant yesterday, but it seems like there shouldn't be any water out there. There's an identical unit right next to it for the lower floor and it doesn't have any water around it, but then it doesn't run constantly, either. It looks like the water is just condensing around the fitting for the copper coolant pipe that goes into the house. It has foam insulation around most of it, so not much is exposed, but there seems to be a lot of water considering the fact that it's 93F out there. The indoor unit drains in another place, so it's not from that.
durning the day it cant keep up and when the sun goes it has no problem and cycles. you go into the attic and it is very hot about 130. i will bet it is even hotter then that in the attic on a 90 degree day. i would tend to think an attic fan would make a world of differance. with all the heat up there and the lights, and stairs you loosing
Nominal 1.5 ton unit is appoximately 16,500 to 18,000 btus ,at 95° outdoors (OD) and 80° indoors(ID),you are wanting 72°,that's 8° less than the standard rating ID.
To adjust for this,even if the room was sized for 72°ID,you deduct835 btus,per 1000 cfms,for every degree below 80°.
8 X 835 X .6(600 cfms divided by 1000 cfms)=4008 loss in sensible btus .
About a half ton of cooling,I'd guess the system is too small,and do the calculations and add a mini-split system ,cooling only as the heat is likely fine ,as is.
Yeah, I wish I made my requirements more clear...
I wish I'd specified more clearly what my temperature requirements were before they installed the system. It just never occurred to me that they would install a system that ran constantly during the summer. That seems like it would wear the system out before long. I'm in Alabama. It's in the 90s during the day all summer long here.
I'm just not sure if this problem has existed since it was installed or is something new. I didn't use the room much for the first year, so I had the thermostat set to 74. However, I can't believe I wouldn't have noticed it not getting below 77F on warm days. Seems like I would have noticed it running continuously, too. If the problem is new, then something is wrong that can be fixed.
I'll put a meat thermometer up in the attic later today and see what the temp is up there. Yesterday, it was 93F outside when I guessed it to be about 130F in the attic.
I like the attic fan idea more than adding a split mini, but I did look up the Sanyo link. A small system would run on a 15 amp circuit, but I'd probably still have to run an additional circuit up there to do it. I might not need an additional circuit just to run a vent fan. I could also beef up the insulation. Some of it got trampled down when I had a roof leak a while back.
I appreciate all the comments. It will give me a better feel for what I'm dealing with without being totally dependent on what the repair guy says. By the way, the repair guy is from the company that installed it. That might limit his objectivity if the unit is under sized...
It's gotta be the attic...
I put the outdoor probe of one of those digital indoor/outdoor thermometers up in the attic, about 18" above ceiling level. Right now it says 122.8F and the room is still 72F. Outdoor temp is 93. Time is 12:30PM, so it probably hasn't peeked, yet.
One thing I did was to go through the attic and fluff up the insulation in the places where it got trampled down. The insulation was probably compressed to about 60% of it's normal thickness in those areas. None of the recessed lighting cans were visible above the insulation, though. If that fluffing makes even a little difference, then there's no doubt that the problem is the trampled down insulation and lack of sufficient ventilation attic ventilation.
I would never have thought that the the ceiling could be that much of a problem during the summer.
Dave, I think I am nearly in the same boat as yourself, and I'm in Atlanta. I, too, think that I have either an undersized unit or an insufficiently insulation second floor or a combination of the two. I also think someone's suggestion of an attic fan might help--I am calling someone this week to get a quote.
Originally posted by dave krueger
You guys probably hate questions like this, but I need to have some idea of whether I'm getting BS from the contractor.
I have a section of my house that is 624 sq ft (outside dimensions) which consists of one large room and one tiny bathroom. The main room has a ten foot ceiling. This room is less than two years old and seems reasonably well insulted: 2x4 walls with fiberglas batting and fiberglas in the ceiling that is at least 16" deep. Three of the four walls are outside walls.
During the afternoon, with outdoor temps in the high 80s or low 90s, the temp of the main room will not drop below 76-77F with the heat pump running continuously. The heat pump is a 1.5 ton unit installed less than a year ago. The air coming out of the ducts is about 58 degrees or so. The filter is new.
Given the duct temp, I'd say the unit is probably working ok which makes me think it might be under sized, but 624 sq ft doesn't seem too large for a 1.5 ton unit. I'm curious as to how much additional capacity is required for a 10 foot ceiling versus an 8 foot ceiling.
I'd be grateful for comments that might help me get a little perspective on this.
Three years ago when I started having a problem the sub-contracting HVAC company claimed the units were only capable of a 10º delta in outside/inside temp. Sorry, that seemed BS, and the next HVAC company I spoke claimed it was BS as well.
Oh well, live and learn. And my zoned unit ran all day yeaterday with nothing on upstairs. Recorded high was 88-89ºF, couldn't get it below the thermostat-reported 74º, while downstairs the reported 74º (separate zone) was much cooler.
Of course, a separate temp-measuring device hanging on the wall at the same elevation read 84º when I went to bed last night (1AM today!). I wish you luck. You are not alone.
Yes, as someone stated, undersized for your application, also you are cooling a basically empty room(no furniture etc), takes more to cool and empty room vs a room with objects that absorb air such as furniture and such, I know it sounds silly , but the laws of physics tell us this.
heat pump problem
The load on the room has to due with the exposed walls and windows, ceilings, electric load, number of people, exhaust fans(infiltration load) and duct loss (attic).
Your largest heat gain is probably your glass windows. If you can keep the sun off of them it would drop the load. Say awnings, eves or reflective coating on the glass, refect the heat before it goes through the glass and is trapped.
What's the CFM of this system?????
Amazing, that up to this point, NO ONE has inquired as to the manual load calc. Did original contractor calculate a load for the space?
Have you contacted the original contractor?
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