Carrier Infinity System - a bit of free advice!
I'm poor at making long stories short, but ...
I had the Carrier Infinity system installed at my new house (including 24ANA a/c and 58MVC furnace).
During the winter, I noticed that the temperature readings were incorrect -- high -- due to sun exposure on the a/c condenser, where the outdoor air thermistor is located.
Because of my lot, and the size of the a/c, there was no shaded location available.
The system uses outdoor temp data for THREE things:
- Display "outdoor temperature" on the thermostat
- Determine the difference between outdoor air temp and outdoor coil temp
- Determine whether, and how much, to roll back indoor relative humidity to prevent condensation
Bad information ... because of sun ... was likely to screw up at least the first two. My HVAC guys said I had to live with it.
Regional Tech Support, similarly, told me to live with it.
Repeated nagging calls and e-mails, however, to Carrier corporate, yielded the following information:
Allegedly, this auxiliary air temp sensor is ALSO the source of the humidity rollback trigger.
Originally Posted by Carrier
The auxiliary sensor was installed today -- in a location selected by Carrier's instructions (north side, up high, covered, etc., etc).
The first problem is solved: the outdoor temp display is accurate. I may test the second function (by freezing the display and watching the RH setting, at the panel) or ... wait until winter.
I presume the third function (OAT vs. OCT temps) is fine, using the sun-enhanced temp.
I can't tell you how many hours and phone calls I had into this. The HVAC contractor finally told me that Carrier wasn't going to "re-engineer the system just for me."
So ... to those considering the system, owning the system, selling/installing the system: you may want to throw in the aux temp sensor for ANY install where the condenser MIGHT receive sun ... at any time of year.
It was a REALLY cheap/easy fix to a REALLY silly problem ... that shouldn't have taken ME so much time and trouble to resolve.
Hope it helps ... somebody
What was so hard about that? We've been doing that for years. I'm still amazed at the information or lack of information provided by tech reps to their customers.
Perhaps you should have read the instructions before calling.
When they installed our Evolution System 2 years ago, the controller came with an OAT Sensor. When I questioned them about it they said it is included for scenarios like yours. So I gues you have to blame the installer for not installing it at the time of the install, unless Carrier does not include them anymore with the controller.
In our case they did not install the OAT sensor because the Outdoor unit is on the North/East side. We do get some high OAT reading in early am when the sun hits the unit.
Part # for Outdoor Air Temperature OAT Sensor
Thanks for the information. I too had an Infinity system installed and my heat pump unit gets afternoon sun so the outdoor temps are off each afternoon.
Q. Anyone have the part # for an OAT sensor that works with the Infinity zone controller board?
Q. How about part # for the LAT and/or HPT sensor?
Since my old system was a Carrier Comfort Zone II zone system I temporarily hooked up a Carrier P/N 920076 but it always diaplsays 75 degrees F on the User Interrface no matter the air temperature.
Any help appreciated.
That can be an issue with any system using an outside sensor, for dual fuel, humidity control, whatever. Hard to beat into the installers' heads, put on the shady side of the house!
OK...I did some research, found in 25HNA6 manual a thermistor ohms vs Temperature chart and cross referenced with a Type II 10K ohm thermistor curve.
Originally Posted by rlpenny
Hope this helps others.
Last edited by beenthere; 11-10-2009 at 05:06 AM.
Reason: Removed DIY info
I am Curious is the sensor on the performance HP located were all the electrical and refrigerant lines are located? If so I know I am going to need the OAT additional sensor.
My HP is located in a corner that will see sun from about 1pm on and the corner with all the hookups is facing the sun. I am worried about it saying it is hotter outside than it really is.
Is the additional sensor included with the infinity controller that I bought and just an optional install item? Our install is mostly done, just waiting for Elect Inspector sign off (they are rediculously slow here), but would like to have my installer install this if they come back out, as I know my unit will get direct sun all summer from 1pm-5pm.
I have the Performance HP and the outdoor temp probe is inside a panel where you connect the thermostat wire coming from the furnace. I've occasionally checked the OD temp reading on the controller. It does read a little high in the summer afternoon when the sun hits it, but that doesn't concern me much as much as how it does in the winter when it controls my hybrid settings. In cooler weather it reads pretty accurately. My feelings are if it's within a couple of degrees, I'm fine with it. You can adjust it with an offset in the advanced menu.
Originally Posted by lamrith
As far as I know the optional OD temp probe for the Infinity thermostat does not come with it.
I can see this being a bit of an issue if you have a straight cool system, but less so with a heat pump. When my unit's not running for hours at a time, the temp sensor DOES read high. BUT once the heat pump starts up the sensor reads very close to the outdoor temp due to all of the airflow around the unit. Then again, my unit is sited so that the sensor faces the building / plants rather than having the refer pipes & panel exposed to the sun.
Correct. The Infinity User Interface (i.e., the main controller) does NOT come with an external temperature sensor for outdoor measurement.
Originally Posted by teaysvalley
However, Infinity condensors or heat pumps do come with a built in temperature sensor (thermistor) that does read pretty accurate once the airflow starts up. As others have alluded to, it really doesn't impact system performance to any degree (pun intended) if it reads high in the sunny afternoons during summer and mine has run more accurate at the lower temps thus far.
The secondary outdoor air sensor is truly an optional and not needed sensor but the geeky engineer types (I'm allowed to say that) will want them. I'm also wanting the HPT and LAT sensors for informational purposes so I'll know the air temperature on both sides of my hydronic coil.
How high off the ground should the auxiliary sensor be mounted? Anyone that can share information on specific's regarding the most ideal scenario in terms of location etc would be most appreciated. My tech is coming by tomorrow as I decided I wanted the Infinity thermostat after all
Originally Posted by NBeener
North side soffit
If your circumstances (home design, ability to have wire run, etc.) I'd recommend having the OAT sensor mounted on the north side of your home in the soffit which puts it in the 7' to 9' range if on a 1-story home or higher if on a 2-story part of the home. Height isn't that critical but I'd prefer it be higher than most folks could reach to keep accidentaly tampering to a minimum. NOTE: I'm just an informed and well read homeowner so take my advice appropriately.
Originally Posted by he8833
Well I have it installed on the North side of the house behind a bush.(no sun) .....and its not picking up the correct temp. Its reading 5-6 degrees warmer than the air temperature.....Its only 1ft off the ground. Although it would be ideal to have it higher to avoid less chance for "tampering" how it could the temp be so far off. Any ideas?
I'm all for it being run higher but the wires coming off the sensor are only 2ft in length. Now thats fine for the current location as their long enough to get through the foundation wall. And then they used wire nuts to connect the 18 gauge 2 wire to the furnace. However if you go outside your going to need to connect the two sensor wires with 18 gauge using wire nuts? Wont this require a box to protect it from the elements then?
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