Carrier Infinity Control Thermostat Problem

[Mylo299]

The first control was 4 degrees off too high the correct room temperature as measured by several different temperature monitors in the same location. The replacement is 3 degrees off too high. Currently the infinity control is set at 71 degrees, and is actually keeping the house at 68 degrees. The same problem with respect to the cooling system occurred this past summer. We had to keep the control set lower to get the actual desired temperature. We googled this issue and found that other homeowners have experienced the same problem, as far back as 2005. Can anyone shed any insight as to what the problem might be? Certainly, this is not acceptable considering the complete infinity system, heating (gas furnace) and cooling was just installed 2 months ago.

[beshvac]

In some cases with the infinity, 3 degrees lower than setpoint is okay. In certain modes the control allows the system to over cool 3 degrees for humidity control.

[Mylo299]

We do not have a humidifier operating with the furnace. During the cooling season, we set the humidity level at the highest point on the control so that this would not be a variable. The issue seems to be that the control is not measuring the correct house air temperature. The technician replaced the unit and while he was standing in front of it, the control was three degrees off compared to his pen thermometer. We have three thermometers all displaying 68 degrees, while the infinity control shows 71 degrees.

[beenthere]

Is there any chance that there is a supply duct in teh wall cavity that the control is installed on.

[mwjhvac]

There is a setting in the control to move the the off set. Have a tech set this.

Offsets:
This option allows calibration (or deliberate miscalibration) of the
temperature and humidity sensors. These offsets are added to the
actual temperature/humidity values (defaults=0).
S Temperature Offset: --5_F to +5_F (--3_C to +3_C)
S Outside Temp Offset: --5_F to +5_F (-

[Mylo299]

Sincere thanks to everyone who has offered help, advice, and suggestions on this topic. The control is not on a wall that has a supply duct. It is in the foyer, about 6 feet from the main entrance door. We previously had a programmable honeywell thermostat and a carrier system without having to consider getting into the offset setting. I wouldn't think the offset setting is designed to compensate for what could be a faulty temperature sensor. By bypassing the problem instead of actually resolving the reason for the faulty operation, this feels like a compromise, which while the system is still new and under warranty, is difficult to accept.

[teaysvalley]

Sincere thanks to everyone who has offered help, advice, and suggestions on this topic. The control is not on a wall that has a supply duct. It is in the foyer, about 6 feet from the main entrance door. We previously had a programmable honeywell thermostat and a carrier system without having to consider getting into the offset setting. I wouldn't think the offset setting is designed to compensate for what could be a faulty temperature sensor. By bypassing the problem instead of actually resolving the reason for the faulty operation, this feels like a compromise, which while the system is still new and under warranty, is difficult to accept.

I have a one degree offset for my indoor temp and 2 degrees for my outdoor offset. I calibrated using a lab thermometer. What makes you so sure your thermometers are correct. Most high tech pieces of electronic equipment give you capabilities to calibrate. So what if they have offsets. As long as they read correctly and consistantly after you calibrate, there is no issue. The Infinfity control is not your everyday programable thermostat you would buy at HD.

[Mylo299]

Agree that there might be a need for one or two degree calibration as you discussed. But a 4 degree discrepancy in one unit, followed by a 3 degree discrepancy in another, makes me uneasy. Various thermometers used have varied within .50 to 1 degree. Having googled this issue, it appears that there could be a quality control issue with the device. I will call Carrier to find out more. The techs who installed the control have said that it is not 'normal' for the unit to be off like this, and they did not even consider getting into the 'offset' setting. We have contacted someone who has this system and they indicated that their unit was 'on point' and did not need offset calibration. I would like to hear from more techs who install these Carrier and Bryant control units whether they routinely have to go into the 'offset' setting. I'm betting they don't.

[stebs]

Have you put a thermometer on the unit to see what it says the temp is right there where the thermostat is? You say its in the foyer near the main door. Is it catching any kind of breeze from there or possibly have sun shining on it through some glasswork?

[joemach]

Agree that there might be a need for one or two degree calibration as you discussed. But a 4 degree discrepancy in one unit, followed by a 3 degree discrepancy in another, makes me uneasy. Various thermometers used have varied within .50 to 1 degree. Having googled this issue, it appears that there could be a quality control issue with the device. I will call Carrier to find out more. The techs who installed the control have said that it is not 'normal' for the unit to be off like this, and they did not even consider getting into the 'offset' setting. We have contacted someone who has this system and they indicated that their unit was 'on point' and did not need offset calibration. I would like to hear from more techs who install these Carrier and Bryant control units whether they routinely have to go into the 'offset' setting. I'm betting they don't.

Which are the same as the Carrier Infinity t-stats. I have seen no variance in temperature reading from my pocket thermometer. If the temperature reading is off on your thermostat and you do not feel that you should have to calibrate it, have Carrier get a new one.

[mwjhvac]

I have never ran into this problem nor needed to offset. I also never seen anyone monitor with so many devices

[2nu2no]

Is the wall penetration for the thermostat and wire insulated at the sub base with plumber’s putty? That would be my first observation, before diagnosing the t-stat

[Mylo299]

I watched the original tech remove the programmable honeywell thermostat and install the infinity control without using plumber's putty. And this could cause the variation? Interesting... Anything else to consider before implicating the unit itself? Thanks.

[tpa-fl]

One bad thermostat, possible. Two bad thermostats? Unlikely. Chances are your thermostat has a draft coming from somewhere. Either behind the unit or there's a supply vent that's nearby. I say move the 'stat to a better location or at least seal up the wall it's hanging on. My Infinity stat agrees completely with my NSF calibrated thermometer, calibrated about every 2 months.

[Mylo299]

The unit is not exposed to a draft. The other thermometers and the 2 previous honeywell thermostats, all registered accurately in the same location. Could the way the unit was wired be affecting this?

[tpa-fl]

The unit is not exposed to a draft. The other thermometers and the 2 previous honeywell thermostats, all registered accurately in the same location. Could the way the unit was wired be affecting this?

I'm still leaning towards a draft/air leak of some sort causing the issue, possibly the hole in the wall where the wires come out. I've seen this sort of thing happen when junction boxes are used for thermostat wire, leaving a large opening behind the thermostat. I usually have these stuffed with insulation then cram a wedge of ductboard in there. Honeywell thermostats usually isolate the thermistor rather well compared to everyone else.

Is your thermostat surface-mounted or recessed? If it's surface mounted it'll extend out from the wall by 1.5". If it's recessed, it's only sticking out by 3/4". If it's recessed, this could well be your problem. The Infinity stat ships with both a recessed backplate and a surface-mount plate. Switch to the surface mount plate and see if it changes anything (after insulating the hole in the wall, that is).

Could wiring problems cause this? Maybe but very unlikely. The sensor is internal to the stat, not like it's pulling the signal over the wiring. Signalling for the Infinity systems is digital as well, so even less chance of something happening. RF interference on digital usually means the signal drops out entirely, which isn't likely with the thermistor mounted directly on the circuit board. No long wire run to act as an inductor. About the only thing that could possibly cause a problem would be low voltage at the thermostat. If the red/blue LEDs flicker/dim when you activate the backlighting, then you've got a severe voltage drop and that's definitely a problem. Otherwise, it's not going to be the wiring.

[Mylo299]

All the units were surface mounted and don't recall seeing any openings. Thanks for your thoughts. I will ask the techs about this.

[AggieEngineer]

Generally there is a hole in the wall for the Tstat wire. It needs to be plugged. Had a guy's house one time getting really cold one at random times. The installer left the back open to the wall and for some reason (outside wind direction or door open or something) would cause a hot draft from the attic to come through the hole causing erratic operation.

[murphy6195]

Until reading Mylo229's problem I thought I was going crazy. My infiinty is 4 yr old . We have it "serviced" every fall and spring.
Right now it is saying it is 62 F and 27% RH in the house. My calibrated thermometer tells me it is 71.9 F in the same spot.

I have no problem calibrating the unit if only I could find instructions for doing so. A pevious post pointed out there were offsets but it did not indicate where. There is nothing obvious on the unit.

[teaysvalley]

Until reading Mylo229's problem I thought I was going crazy. My infiinty is 4 yr old . We have it "serviced" every fall and spring.
Right now it is saying it is 62 F and 27% RH in the house. My calibrated thermometer tells me it is 71.9 F in the same spot.

I have no problem calibrating the unit if only I could find instructions for doing so. A pevious post pointed out there were offsets but it did not indicate where. There is nothing obvious on the unit.

Press and hold Avanced button for 10 secs. Setup>Thermostat>Offsets>Temperature Offsets. You can only change it +/- 5F. I would check it with another thermometer first and place it right on the controller.