Troubleshooting Honeywell Thermostat (TOP 5 Most Common Problems with DIY Solution)

Troubleshooting Honeywell Thermostat

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 about troubleshooting Honeywell thermostat.

So you have a Honeywell thermostat and it’s not working properly and you want to troubleshoot and repair it yourself.

Let me tell you something I have been in the HVAC business for 6 years now and I have repaired hundreds of Honeywell thermostats. I know what’re the most common problems in the Honeywell thermostat and how you can repair it yourself.

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

Troubleshooting No. #1: Misplacing Wires (Putting 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 if it’s not working or creating any kind of short in the wiring. Then you must check the thermostat wiring. You might have placed the wrong wires in the wrong section and it is causing problems.

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 = Fan – Green wire

Y= Cooling – Yellow wire

W= Heating – White wire

R= Power – Red Wire

Rc= Power to Cooling

Rh= Power to Heating

C= Common – Blue Wire

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 wire (Blue wire) on the B terminal (as they think B for blue).

But the blue wire goes to the C terminal of the thermostat. If you put blue wire on the B terminal it might touch other wires and cause a trip/short. Also, you must check all the terminals and wires properly. Every wire should go into their respective terminals or they’ll create problems.

Also, Check Our Thermostat Bypassing Tutorial Click Here

Troubleshooting No. #2: Placing Jumper Between R and Rc/ R and Rh:

If you recently replaced your thermostat and your ac or furnace is not turning on. So you might want to check in the jumper that is placed between the R and Rc & R and Rh. R terminal is for power with the 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 & R and Rh. You must check for the jumper.

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 then just place a jumper in between them and check. If everything works then the jumper was 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 the furnace and ac to work.

Sometimes what happens is the new thermostat came with a setting to electric or heat pump. And this can cause your ac or furnace to not work. You must check that button and set it to gas and oil.

Troubleshooting No. #4: Check Wires On Control Board and Thermostat      

Most of the time what happens is after replacing the control board or thermostat. People place the wires on the wrong sections. You must check your control board and thermostat wiring.

If something is not working then you might have placed the wrong wires on the wrong terminals. This mistake can be easily overlooked as it is easy to get confused in the writing color code.

Troubleshooting No. #5: Make sure that you buy a Right Honeywell Thermostat  

You need to make sure that you’re buying the right thermostat. Sometimes what people do is they end up buying 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 bit about the C wire, it usually provides a return path so that the thermostat can be powered without disrupting the other wires.

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 and that can cause battery drain. So using 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.

Few More Tips On Thermostat That You Must Check

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 the fuse. You must turn the power off to the thermostat before removing it. 

Tip No. #2: Checking Bad Installation 

A bad or loose installation of the thermostat can cause problems down the road. Sometimes the technician doesn’t install the thermostat properly and it becomes loose over time and which can cause wires to dislocate from their location. You must check the thermostat from time to time.

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

You must check all the functions like fan, cooling, 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.

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