(fyi, totally not trying to DIY here -- just trying to see if anyone else can figure out what our HVAC installer can't, so we know which way to turn with this!)
Three years ago, I had a two-zone system put into my house (one for 1st floor, the other for 2nd and attic, in old house). We have two Carrier heat pumps, blowers, and thermidistats.
The first floor system works perfectly, but in the 2nd/3rd floor system (with identical equipment), they've already replaced thermidistat twice and it still has the same problem (though it's no longer under warranty): When the AC is on, the temperature in the room where the thermidistat is mounted is frequently at least 4-5+ degrees lower than the setting or reading. It will be set to 75, it will say it's 76 (so still running) but a thermometer set just a foot away will read 70 or lower. We've confirmed the accuracy of the thermometer we're using several times, our HVAC contractor's professional thermometer confirmed that this was happening, and the fact that we find ourselves freezing confirms the lower temp as well.
And this is just the room where the control is mounted -- one of the other bedrooms has gotten at least 8 degrees cooler than the reading on the thermidistat.
So he's replaced it twice, but we still have the same problem -- but it's not consistent enough to, say, set it at 80 and know it will actually be 75. If we set it at 80 sometimes it will actually be 80, and sometimes it will actually be 72. In the mean time, the 2nd floor system is running like crazy, to the point where the first floor is cooled several degrees lower than where it's set.
This appears to be independent of the fan setting, the humidity control setting, or anything else (or at least anything else we've thought to check). It also only happens with cooling - the temp is always very accurate with heating.
If anyone has any clue as to what might actually be the cause of this, I'd appreciate it. I really don't want to go with a different HVAC company, both because I trust and like these guys, plus I don't want to spend $$ for yet another company to come in and scratch their heads and say, "well... no idea what's going on." I'm hoping instead to start with seeing if anyone else has encountered this, so that I can then talk to my contractor and ask him to consider whatever's been suggested here that makes sense.
Thanks for whatever ideas you might have, or for sharing whatever similar experiences (and solutions!) that you can share.
Three years ago, I had a two-zone system put into my house (one for 1st floor, the other for 2nd and attic, in old house). We have two Carrier heat pumps, blowers, and thermidistats.
The first floor system works perfectly, but in the 2nd/3rd floor system (with identical equipment), they've already replaced thermidistat twice and it still has the same problem (though it's no longer under warranty): When the AC is on, the temperature in the room where the thermidistat is mounted is frequently at least 4-5+ degrees lower than the setting or reading. It will be set to 75, it will say it's 76 (so still running) but a thermometer set just a foot away will read 70 or lower. We've confirmed the accuracy of the thermometer we're using several times, our HVAC contractor's professional thermometer confirmed that this was happening, and the fact that we find ourselves freezing confirms the lower temp as well.
And this is just the room where the control is mounted -- one of the other bedrooms has gotten at least 8 degrees cooler than the reading on the thermidistat.
So he's replaced it twice, but we still have the same problem -- but it's not consistent enough to, say, set it at 80 and know it will actually be 75. If we set it at 80 sometimes it will actually be 80, and sometimes it will actually be 72. In the mean time, the 2nd floor system is running like crazy, to the point where the first floor is cooled several degrees lower than where it's set.
This appears to be independent of the fan setting, the humidity control setting, or anything else (or at least anything else we've thought to check). It also only happens with cooling - the temp is always very accurate with heating.
If anyone has any clue as to what might actually be the cause of this, I'd appreciate it. I really don't want to go with a different HVAC company, both because I trust and like these guys, plus I don't want to spend $$ for yet another company to come in and scratch their heads and say, "well... no idea what's going on." I'm hoping instead to start with seeing if anyone else has encountered this, so that I can then talk to my contractor and ask him to consider whatever's been suggested here that makes sense.
Thanks for whatever ideas you might have, or for sharing whatever similar experiences (and solutions!) that you can share.
