I was scared seeing my Honeywell thermostat blank screen after changing batteries because it was still in tiptop condition. I am sure, a blank thermostat is terrible news for most households as well.
Let me assure you first, it’s not always a serious issue. But to prevent future problems, you need to fix the issue quickly.
There could be plenty of reasons why is your thermostat display not working. I will cover all those probable reasons and exactly what you should do to solve the problems. Keep reading!
Common Reasons for Blank Thermostat Screen
A blank screen not necessarily means your air conditioner, heat pump, or furnace is broken. In fact, there are some easy fixes that I am about to talk about.
But first, I think you should know why the thermostat is not working in the first place. Once you know the reasons, you can come up with your own solution. Here are some common reasons:
- It’s Turned Off!
If you are not living alone, maybe someone else has turned it off unwittingly or knowingly. So, you are seeing the blank display simply because it’s turned off! It does not hurt even a bit to check whether it is turned or not.
- Tripped High-Limit Switch
If your thermostat is running for a longer period of time, it will reach its max capacity for a single period of time and trips its high-limit switch to protect it from overheating. That’s when you can see a blank screen.
If that’s the case, let it cool down for a while.
- HVAC Power Is Off
Some HVAC system has their own power switch and if it’s turned off, switch it back on the ‘On’ position without wondering why is your thermostat is blank.
- Low Brightness
Most of the battery run electrical equipment automatically reduce the brightness level when exposed to too much light to save the battery life. These thermostats have their own programmable feature where users can set their own brightness level.
The same may be true for your thermostat. If the brightness is set to too low, you will see a blank screen.
Before you go on the repairing mode or next level of seriousness, double-check the brightness level. If the brightness level is set to medium to high, move to the next cause.
- Dead Batteries
If your thermostat is not hooked up with the HVAC system, it runs on some batteries most likely. And whenever the batteries run out of juice, you see a blank screen.
Even if it’s hooked up with the HVAC system, you can still see the blank but will explain that later.
Replacing the old batteries with the new ones will solve the problem. It’s probably 3-volt lithium or AA alkaline batteries. But you should check the old batteries before you get the new ones.
But let’s see why you see the blank screen even your thermostat is connected with the HVAC. During the middle of recharging the thermostat, it can still show you the blank screen.
The display should return momentarily and if it does not, keep reading…
- Loose Wiring
You should look at the most obvious reasons first when you deal with such problems. A wiring problem or simply a loose wire connection may be the reason your thermostat is not having the power to keep it functioning.
There are plenty of reasons why you can have a loose wiring scenario. Maybe the thermostat is in a crowded place and the vibrations from the people walking make create a loose connection scenario.
Sometimes, rats and rodents affect the wiring chewing it. You can fix the loose connection yourself only if you have an electrical background.
Again, if you are confident, you can run a diagnosis or call an electrician to do the same for you.
- Blown Fuse or Tripped Circuit Breaker
If your thermostat is on the same circuit breaker that is used by other heavily electricity consuming devices, the circuit breaker may trip sometimes upon voltage instability.
A tripped circuit breaker also means your thermostat has no power connection, so you are seeing the clear screen. The same will happen for the blown fuse too.
Simply flip the circuit back on and your thermostat should come back in life. If you have fused, you must replace the fuse.
If should fix the problem. If not and the circuit breaker trips or fuse blows again, call a professional to fix the HVAC problem.
- Tripped/Triggered Safety Switch
Your HVAC system has a safety switch as a safeguard against the unsafe situation of voltage instability. Just like the fuse or the circuit breaker, you may have a tripped safety switch problem as well.
And if you do, your unit won’t have any electricity supply from the transformer and you will see a clear screen problem. Fixing the tripped safety switch is not as easy as fixing a blown fuse.
If it’s the faulty air conditioner or the heat pump you are dealing with, check whether the condensate pan is full or not.
However, doing so will trip the switch. Make sure to empty the pan and check whether the electricity is restored to the thermostat or not. If not, call a professional.
You should call a professional if it is the furnace you are having trouble with instead of wondering why is your thermostat display not working.
- Check The Furnace Door
It’s worth checking to solve the problem according to the many professional electricians. Some thermostats will turn off if the furnace door is not closed properly.
Of course, this level of sensitivity varies according to the brands you are using. But it’s worth a shot closing the door securely to see if the problem goes away or not.
- Old Thermostat
It will simply give up when it’s really old. If everything mentioned above checks okay and yet it still not working, maybe the service life of your thermostat has simply expired.
On average, a typical thermostat lasts around 10 years. If yours is older than that and you don’t see any other fixable problems, it’s time to replace it with a new one.
Here is a short video explaining how to fix the blank screen problem of your thermostat.
I ordered the above causes in an orderly fashion from the easy to fix to hard nut to crack. You should follow that order to fix the blank thermostat problem without fretting.