All Trane 624 Thermostat Problems and How To Fix Them

While Trane 624 is an excellent thermostat to have in your home, it’s unfortunately common for it to run into issues. Since your thermostat controls the HVAC system and ensures the temperature and humidity of your home are comfortable, it’s important to ensure your thermostat is working.

Trane 624 thermostats can run into issues like failing to run despite being turned on, overcooling or overheating, and even failing to work entirely. Most issues can be fixed by configuring your thermostat, but you may need to troubleshoot the HVAC system or call an expert for more complex issues.

In this article, I’ll be examining the most common issues that occur with Trane 624 thermostats and how you can fix them. I’ll also be highlighting scenarios where you may need to do complicated troubleshooting or call a technician. 

1. Fan Is Set to ‘On’ but Not Running

One of the most common issues Trane 624 thermostat users encounter is that their fans won’t run when they turn their system on. This issue is generally caused by an improperly configured thermostat, but it can also be caused by a broken system. 

How To Fix?

Check the system to see if the cooling target humidity is lower than the current indoor humidity. If the humidity in your home is higher than the thermostat’s settings, raise the target cooling humidity above the current indoor humidity to resolve the issue. 

You can also disable the Smart Continuous Fan (SCF) setting. Since the SCF feature automatically controls the HVAC system to keep your home’s humidity and temperature at ideal levels, however, you have to manually control your system without it. 

If raising the cooling target humidity above the current indoor humidity and disabling SCF doesn’t resolve the issue, you should check to see if your HVAC system needs expert repair services.

Read: Trane Thermostat Error Codes – Troubleshooting Guide

2. Heating/Cooling Turned On but Not Pushing Air Out

If you need to cool or heat your home, it can be frustrating to turn the thermostat on only to find that it won’t push any air out of the vents. There are a few configuration issues that can cause this problem with Trane 624 thermostats.

How To Fix?

The two most common causes of a Trane 624 thermostat not pushing air out of the vents when set to heat or cool are an unexpired fan delay time and a dysfunctional HVAC system. 

To fix them, do the following: 

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  • Verify that the thermostat doesn’t have an unexpired fan delay time. Wait at least one minute to see if the blower delay ends, and then check the vent grills to see if it has started pushing air out. 
  • If the thermostat won’t push air out of the vents even when the fan delay has expired, you should check the system thoroughly for any wiring issues. You may also call an HVAC professional. You can also try overriding the thermostat.

In some cases, you may notice your Trane 624 thermostat doesn’t work and doesn’t display that it was set to heat or cool the room. For the system to function properly, the desired temperature and delta “on” temperature should be set below the room’s current temperature to cool it or above the room’s temperature to heat it.

Read: How To Override A Trane Thermostat?

3. Trane 624 Thermostat Incorrectly Displaying Temperature

Knowing what temperature it is inside your home is important for you and your thermostat. Unfortunately, there are a lot of issues that can cause your Trane 624 thermostat to read the temperature incorrectly.

Before attempting to troubleshoot the thermometer, use a household thermostat for calibration. Tape your household thermostat next to the Trane 624 thermostat and leave it for 5 minutes to allow it to get an accurate reading. Then, check the difference between the actual temperature and the displayed temperature.

How To Fix?

To fix your thermostat’s temperature display, you should start by removing the cover and cleaning the thermostat. You may also need to replace the air filters in your HVAC system. Then, allow the system to run and see if the reading becomes accurate.

You should also check if the heat from the thermostat’s touch screen is being trapped, resulting in an inaccurate reading. If the body of the control seems strangely warm, relocate the touchscreen and ensure the system is properly ventilated.

Another potential cause of your Trane 624 thermostat displaying the incorrect temperature is air infiltration. Look at where the thermostat’s base plate is installed to verify that the wire hole is caulked. If not, you should add caulk around the wires to ensure the temperature reading is accurate.

Lastly, make sure your thermostat is wired correctly. If the thermostat is connected to the wrong temperature sensor, it will display the wrong temperature — and unfortunately, this is a common issue with installation. You may need to rewire your HVAC system or call an HVAC professional to have the issue resolved.

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Read: 4 Reasons Why Ecobee Thermostat Fan Keeps Running

4. Overcooling or Overheating Past Set Temperature

When your thermostat is overcooling or overheating your home to uncomfortable extremes, it can be a frustrating experience. There are a few common configuration issues that can cause overcooling and overheating — and luckily, it’s an easy issue to address.

How To Fix?

If your Trane 624 thermostat is overcooling or overheating the room, start by setting the delta “Off” to 0. For overcooling specifically, you may also need to disable cooling overshoot or change the cooling target relative humidity to a higher number. Lastly, you should change the compressor or indoor heat on time to a lower level.

You should also verify that your system is wired correctly. If the thermostat is receiving the temperature from the wrong sensor, it won’t be able to detect when the room is cool enough. You can verify this by checking whether the temperature shown on the display is accurate.

5. Thermostat Display Won’t Turn On

It’s easy to notice when your thermostat’s display won’t turn on. Considering that you won’t be able to control your home’s heating or cooling until it’s fixed, this is an important issue to address.

How To Fix?

Typically, the reason a Trane 624 thermostat display won’t turn on is that the batteries are dead. To start troubleshooting this issue, you should replace the thermostat’s batteries. If that doesn’t resolve the issue, try resetting the circuit breaker.

If these solutions don’t work, you should call an HVAC professional to investigate other underlying causes. If the R and C wiring or transformer has failed, the thermostat may not be receiving the 24V AC power it needs to function. 

If you can get the display to work in any form, you should check for the E4 Trane Error Code. This will let you know if the input voltage is out of range.

6. Trane 624 Thermostat Incorrectly Displaying Humidity

Like an incorrect temperature reading, an incorrect humidity reading on your Trane 624 thermostat can be frustrating — and it can cause the HVAC system to behave strangely too. This is generally the result of an uncalibrated humidity sensor.

How To Fix?

If your humidity sensor isn’t working properly, it will send incorrect readings to your thermostat. To resolve this issue: 

  1. Calibrate your humidity sensor to the correct settings. Start by getting a working humidity sensor and taping it to the wall next to the dysfunctional sensor. 
  2. Wait several minutes for the sensors to grab accurate readings. 
  3. Once you have readings from the dysfunctional and the working humidity sensors, navigate on your Trane 624 thermostat to Menu → Settings → Thermostat → Indoor Calibrations and adjust the humidity to the correct setting.

If the thermostat continues to deliver an inaccurate humidity reading, you must inspect the system or call an HVAC expert for repairs. 

7. Thermostat Fan Runs All the Time

One of the most frustrating issues with Trane 624 thermostats is that their fan never stops running. This can make the temperature of the home extremely uncomfortable, and it can waste a lot of power too. This problem tends to occur due to misconfigured settings.

How To Fix?

If your thermostat fan is running all the time, start by checking what the fan mode is set to. If it is set to “on” or “circ,” change the fan mode to “auto.” This will make it start and stop automatically, depending on the temperature and humidity of your home.

If changing the thermostat fan setting doesn’t resolve the issue, you need to check the function of the system or call an HVAC repair specialist.

Final Thoughts

It can be an extremely frustrating issue when your Trane 624 thermostat isn’t functioning normally. Whether they’re causing your home to reach uncomfortable temperatures or even preventing you from controlling your HVAC system entirely, it’s important to address thermostat issues as soon as you notice them.

With the right troubleshooting methods, repairing a malfunctioning Trane 624 thermostat is simple. And if conventional troubleshooting doesn’t work, you can rely on the expertise of an HVAC technician to get your home’s thermostat working as intended.