Troubleshooting Honeywell Thermostats: Top Most Common Problems with DIY Solutions

A thermostat is one of the most important parts of any HVAC system. A single problem can lead to the whole system not working. There are different thermostat brands, but in this guide, we'll talk specifically about troubleshooting Honeywell thermostats.

So you have a Honeywell thermostat that is not working correctly, and you would like to troubleshoot or repair it yourself. I have been in the HVAC business for many years and have repaired hundreds of Honeywell thermostats. I know the most common problems with Honeywell thermostats and how you can repair them yourself. A thermostat is a crucial component of HVAC machinery. Thanks to these devices, we can easily adjust the temperature in our home or place of business, which results in long-lasting comfort. A Honeywell thermostat is among the most widely used of the many different types of thermostats available.

Even though these gadgets are excellent at keeping us comfortable, issues occasionally arise. We'll discuss some of the typical Honeywell thermostat issues in this post, along with some troubleshooting advice.

In this guide, I'll list all the common problems that can occur in the Honeywell thermostat and how you can repair it yourself. Repairing and troubleshooting the Honeywell thermostat is easy; follow the steps below.

Working Honeywell Thermostat

Is your Honeywell thermostat completely unresponsive? It can be challenging to solve this issue. Fortunately, you can try some simple steps to fix the problem.

Check the settings on your Honeywell thermostat.

To begin with, you can check the settings on an analog Honeywell thermostat to ensure they are set properly. You'll see that your thermostat has two switches: one for the fan's power and another for the heat, calm, and off. Turn on the heat setting and increase the temperature to see if that helps to resolve the issue. If it does turn on, your luck is in.

It's time to check your air conditioning right now. Set the fan to auto and the thermostat to the cool position. Reduce the temperature, after which wait a brief period. You're good to go if you hear the system is in operation. If not, another problem might be present.

Examine the unit's interior

If your thermostat is completely unresponsive, there might be an internal issue. To determine if there is a problem, you could look inside the thermostat. Turn off the power source to your thermostat by going to your electrical breaker box. The thermostat should be turned off before carefully removing the unit's top cover. Check the wiring to see if anything is disconnected, broken, or loose. Additionally, make sure everything is clean.

Your issue might be caused by dirty wiring or a dirty interior of your thermostat. If there are no problems under the cover, your HVAC system may malfunction, or you may need to replace your thermostat.

Blank screen on the Thermostate

A display screen that is blank when everything is turned on is another frequent issue. Fortunately, some Honeywell thermostat troubleshooting advice is available.

You may have dead batteries if your digital thermostat has a blank screen and doesn't display anything. Check to see if it helps to change your batteries.

If that isn't the problem, your HVAC system might be the cause. If an access door on your HVAC unit isn't completely closed, your screen might appear blank. A switch that enables the unit to function is activated when these doors are shut. This switch is off when a door is open, which prevents the system from operating. Make sure to inspect your unit and close all access doors.

Another possibility is that your circuit breaker has tripped. Additionally, a blank screen on your thermostat may result from this. Check the HVAC unit's circuit breaker to ensure the switch is in the proper position. HVAC units frequently have their own circuit breakers.

The thermostat from Honeywell won't turn on the heat

Does your thermostat fail to keep the house warm? Alternatively, does your thermostat never turn on the heat? In this case, if your display screen is blank, check your batteries. If the screen on your display is functional, check your wiring to see if there are any problems.

Make sure your thermostat is perfectly leveled, as another piece of advice. If it isn't, the thermostat's mercury switch could result in an inaccurate temperature reading. This may result in your system turning on and off repeatedly. Make sure your thermostat is perfectly level to try to resolve the problem.

The thermostat Reading Is Incorrect For the Temperature

Do you have a Honeywell thermostat that won't cool? Or does the temperature reading appear to differ from the actual temperature inside? There might be a problem with the temperature sensor in this case. Grab a thermometer and check the actual temperature close to your thermostat to diagnose the issue.

If these temperatures don't line up, there might be a sensor problem. You have two options: swap out the damaged sensor, or get a new thermostat.

Troubleshooting No. #1: Misplacing Wires (Putting the Wrong Wires in the Wrong Socket)

If your Honeywell thermostat is not working or creating any kind of trip in the fuse/breaker, then the main reason for this problem is misplaced wiring.

If you recently replaced your thermostat and it’s not working or creating any kind of short in the wiring, you must check the thermostat wiring. You might have placed the wrong wires in the wrong section. This can cause many problems for your thermostat.

Steps To Check Your Thermostat Wiring:

Step 1: First thing you need to do is remove the thermostat cover.

Step 2: After removing the cover, check all your wires. The main thermostat terminal will be labeled as:

G (Green Wire) = Fan

Y (Yellow Wire) = Cooling

W (White Wire) = Heating

R (Red Wire) = Power

C (Blue Wire) = Common

RC = Power to Cooling

RH = Power to Heating

Step 3: Now check for the common wire. You might have placed it on the B terminal. Most people do this by mistake. They put common (blue) wire on the B terminal (as they think B for blue).

But the blue wire goes to the C terminal of the thermostat. Putting blue wire on the B terminal might touch other wires and cause a trip/short. Make sure to check all the terminals and wires properly. If every wire is not in its respective terminal, it will create issues that impact your thermostat's performance.

Troubleshooting No. #2: Placing Jumper Between R and RC or R and RH

If you recently replaced your thermostat and your ac or furnace is not turning on. So you might want to check on the jumper placed between the R and RC and the one connecting R and RH. R is a terminal for power with a red wire connecting to it.

RC means Power of Cooling, and RH means Power of Heating. There will be a jumper in between the R and RC, along with one for R and RH. You must check for these jumpers. Sometimes after replacing the thermostat, most people forgot to put the jumper in between these terminals, and then nothing seems to work.

If you think these terminals and jumpers are causing the problem, just place a jumper between them and check. If everything works, then the jumper is the problem.

Troubleshooting No. #3: Set Your Honeywell Thermostat To Gas And Oil

If you tried to replace the thermostat recently. Then you might not know that there is a button on the back of the thermostat which must be set to gas and oil for some of the furnace and ac systems to work.

Sometimes it happens that the new thermostat comes with a setting to an electric or heat pump. This can cause your ac or furnace to not function. You must check the button on the back of the interface to guarantee that your thermostat is set up to run with the corresponding system.

Troubleshooting No. #4: Ensure that You Bought the Right Honeywell Thermostat

You need to make sure that you’re buying the right thermostat. Sometimes people buy a thermostat that doesn’t have a common section in it (Battery powered thermostat).

So you must choose a thermostat that does have a common section. A little about the C wire, it usually provides a return path so that the thermostat can be powered without disrupting the other wires.

The thermostat screen blackout can be caused due to the c wire. So most thermostats will have different features like wifi or a screen to display, which can cause battery drain. So using a C wire can give you constant power, which can be used in case your battery dies.

You can also buy a two-in-one thermostat which has a battery and c-section.

Tips to Keep in Mind When Replacing a Thermostat

Tip No. #1: Check Before Replacing Your Thermostat

Sometimes people just remove the thermostat normally without taking any precautions. You must remember that there’s current in those wires, and if you move them recklessly, they might end up tripping or blowing a fuse. You must turn the power off to the thermostat before removing it.

Tip No. #2: Checking Bad Installation

A bad or loose thermostat installation can cause problems down the road. If the technician doesn’t install the thermostat interface properly, it will become loose over time. This can cause wires to dislocate from their location. You must check and potentially tighten the thermostat from time to time.

Tip No. #3: Proper Inspection After replacing the Thermostat

You must check all the functions like the fan, cooling, and heating of the thermostat if you recently replaced it. You need to make sure that all the functions are working properly. Also, if you’re replacing your thermostat by yourself make sure to cut the old head of wires and strip it down a bit.

Always select a reputable HVAC consultant

Because of their increased sophistication, it can be challenging and frustrating to troubleshoot these issues with Honeywell thermostats. Anytime you have a problem with your HVAC system or any of its components, calling an HVAC expert can be a very wise move.

The following are risks associated with servicing your HVAC system:

electric jolt
causing systemic damage
causing harm
Increasing the difficulty
causing yet another issue
voiding the warranty on your system

While changing batteries or making a small adjustment to your thermostat is not dangerous, working with your HVAC system's electrical components can be very dangerous. We strongly advise calling an HVAC expert if you ever feel uncomfortable troubleshooting issues with your thermostat or HVAC system. They are adept at what they do and can identify the issue quickly.

Pay attention when installing your thermostat to try to prevent future thermostat issues. Learn how to operate a Honeywell thermostat so you can ask questions about common thermostat issues. Your Honeywell thermostat should also include a manual, and that manual should include a section on Honeywell thermostat troubleshooting. When attempting to solve these issues, this can be a valuable resource.

It might make sense to purchase a replacement thermostat if you frequently experience thermostat problems. Over time, this equipment degrades, and a new model may offer numerous benefits. In fact, since your old thermostat may have contributed to your home's inefficient use of energy, replacing it with a new one could result in significant energy cost savings.