Carrier Infinity Thermostat Replacement/Evap Icing

[Buckaroo5]

Posted on this forum last week about replacement needed for circa 2002 Carrier Infinity Thermostat. Thanks to all that responded but the thread was blown away in the recent GJ server issue.

To update, very happy that the original installing HVAC contractor replaced the thermostat under warranty with the SYSTXCCITC01-B. Current problem - we have had two occurrences of evap icing to the point that air flow was severely limited but no error messages. Did not have this problem before the new thermostat. We will of course have the contractor back out if needed but trying to understand potential causes. Looking to make sure we do not have restricted air flow but nothing else was done to the HVAC system except the thermostat replacement....perhaps thermostat set-up incorrect? Suggestions where to look?

Buckaroo

 

[yeldogt]

Does the fan seem to be going through all the speeds ... there are fan limitations.

The system should go through a fan/duct/cfm test .... I wonder if this was lost with the new thermostat

 

[Buckaroo5]

I think that static pressure test is a step in the thermostat install? Have a copy of the install manual and going to read about it. One thing, the humidifier damper was in the winter position (open) when the tech installed the thermostat. My son and I corrected it after the first icing incident and had a conversation about humidifier operation and maintenance. But the icing happened again. Maybe the static pressure test step needs to be repeated? Does the system only do the test when commanded or does it do it periodically on it's own?

 

[Buckaroo5]

Regarding your question about the fan going through the speeds - do you mean is it ramping up to high speed?

 

[yeldogt]

I think the default is for the system to test everyday .. at 1am. But -- I believe that's more to make sure there is no greater restrictions ... I'm not sure if it fully resets

When it ices up -- what is the status of the compressor when you pull up the stage. I forget was this a two stage unit ?

Did you run the system in constant circulation prior ?

Did they change the filter?

Freezing coil is often low refrigerant ....But, the system should catch that with an error code. Did my first Infinity I guess around 04 (2 speed) .... so that's the earliest one. I don't own the house any more ....