Carrier Infinity Thermostat Blank Screen [Fixed]

Are you wondering why you have a carrier Carrier infinity thermostat blank screen? If so then this guide will be helpful because we are going to be talking about all the common causes for the problem and all their possible solutions

Generally if your Carrier infinity thermostat has a blank screen this could be due to an overflow pan that is filled up and trips the switch, open furnace door,loose thermostat wires, tripped breaker or a blown fuse.

The table below shows a summary of the most common causes for this problem and the possible fixes

5 Possible reasons a Carrier infinity thermostat has a blank screen

Possible cause	Main fix
Dead thermostat batteries	Replace batteries
Loose thermostat wires	Check the wiring
Open door furnace	Close door furnace which has a switch
Blown fuse	Replace the 5 or 3 Amp fuse
Tripped circuit breaker	Reset the tripped Switches

Here are the detailed steps on how to troubleshoot the problem

Dead thermostat batteries

Dead batteries could be the first possible reason why your carrier infinity thermostat has a bank screen. There are models that use batteries and those that don’t use batteries but are powered by the C wire.

For carrier infinity models that use batteries, when these batteries die your thermostat will have a blank screen, you won’t see anything on the thermostat.

However in most cases you will have signs of dying batteries even before they die out. Here are some symptoms for a dying battery.

Faint display
Display abruptly going on and off
AC thermostat hardly responding to thermostat adjustments and
A thermostat’s display that completely goes blank.

In many cases a thermostat is programmed to warn you about your dying battery approximately 2 months before your battery completely dies out.

If you think you have flat batteries, replacing them with new ones should fix the problem

Loose thermostat wires

Another possible cause for the blank screen on your carrier thermostat could be loose wires.

Carrier infinity thermostats are communicating system thermostats that allow all three components of the HVAC system namely, outdoor unit, indoor unit and the indoor controller to communicate to each 24/7.

That means these thermostats have only four terminals that are wired A,B,C,D and out of these wires, C and Dcarry voltage and the reset transmit data.

Troubleshooting this issue might need to use a multimeter and test terminal C and D for continuity. Under normal working condition this should register 24 volts but fs there is no continuity ensure that the wires are firmly attached to the pin connectors

However, in some cases where this wire becomes loose from the thermostat terminal or dirt accumulates on it, that could also cause power issues and you thermostat screen to go blank

So ensure that the wires are in direct contact with the terminals and are tightly attached. This should solve the problem.

Open door furnace

Since a blank display on any thermostat means power issues, your thermostat could have a disconnection from the air handler. In many cases this is due to an open door furnace.

Furnace doors are equipped with switches which turn off power to the HVAC system when it is open.

There may have been someone within your household or office who had forgotten to firmly close the door after a routine filter change. Check on the air handler door and if everything looks good, move on to the next step of the troubleshooting.

Blown fuse

A blown fuse on the circuit control board of your furnace could cause a blank screen issue on your carrier infinity thermostat. Fuses protect your equipment and your thermostat from damage when there is a surge. The system’s fuse is typically located on the control circuit board.

To test it, you might want to use a multimeter to check if there is continuity, that is, if you can’t tell by looking.

Replace the fuse if necessary.

Tripped circuit breaker

Tripped circuit breaker could also cut power to your thermostat and this can cause your thermostat to have a blank screen. If there are tripped breakers you might want to flip them back

but be careful, the purpose of the breakers is to protect your equipment from damage when there is a power surge.

So there could be a short that could have caused the circuit breakers to flip. You can know the breakers trip again after flipping them back. You should call a professional if that is the case.

Tripped safety switch

HVAC systems come with a number of safety switches. These switches ensure that your system is protected from damage and also for your safety. When the safety switch is tripped the transformer supplying power to your system or possibly thermostat will stop and this causes a blank screen on your thermostat.

In case you are using a heat pump you might want to take a look at the condensate pan to see if it’s full. When this is full, it will trip the safety switch.

Defective thermostat

If nothing works, your thermostat might have just served its purpose in your house and needs a replacement. This can be the case especially if your thermostat is 8 years old or over.

Replacing the thermostat should fix the problems.

Final thoughts

As we have seen there are only a few issues that can cause your carrier infinity thermostat to have a blank screen. If nothing works out it’s probably high time you invested a little in a new thermostat or consult a local HVAC professional for advice.

More resources

https://www.hvac.com/troubleshooting/carrier-thermostat-troubleshooting/

Shalom.