Normally, when the “cool” light starts flashing on your honeywell thermostat, there’s nothing to worry about. this usually means that the air conditioning unit is starting to work.
If you leave it for a couple of minutes, the light should go out when the air conditioner starts working properly.
However, if the light does not turn off after 5 minutes, this could mean there is a bigger problem. It can be confusing trying to figure out how to fix the problem, especially if you don’t have the manual handy!
We will guide you through some steps you can take to solve your problem.
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why is my honeywell thermostat flashing “cool”?
so before we talk about how to classify a honeywell thermostat that constantly flashes “cool”, we need to know more about how it works. the “cool on” light is one of the operating modes that your thermostat controls.
Like the “heat” setting, “cool” just tells you that the thermostat is starting to cool your home.
You should be used to seeing “cool on” flashing on your thermostat for short periods of time. this does not necessarily mean that something is wrong with your thermostat. this is a safety measure that comes with the thermostat to protect the compressor.
The “cool on” function allows the system to run through its elements so it can do its job properly. if you have a power outage, you can also flash then.
how to troubleshoot the “cooling” light
Don’t you feel cold air entering your system? Has the “cooling” light been flashing for much longer than 5 minutes? then we have some solutions for you to try and we hope they will help you solve the problem.
lowest thermostat setting
One of the easiest solutions is to test if your thermostat can control the cooling in your home. turn it down to the lowest setting and leave it for an hour or two to see if the temperature changes at all. it could be as simple as the system just needs to cool down.
make sure your honeywell thermostat is set to “cool” mode and the fan setting is set to “auto”. set the thermostat to the lowest temperature reading possible.
Once it has been left to do its job, check to see if anything has taken effect or if there is a change in temperature in your home.
Is the clock set or is the thermostat in setup mode?
One factor that can cause your honeywell thermostat to flash “cool on” repeatedly is when a power outage has occurred. If you came back from vacation and noticed your thermostat flashing “cool on” repeatedly, it could be an indication that this has happened.
no need to panic! all this means to your thermostat is that it has switched back to setup mode. this can cause the “cooling on” light to flash repeatedly. once you’ve set your thermostat back up, this problem should resolve itself.
It’s also worth checking the time setting on your thermostat to make sure it’s not turned off or showing as set. this could also be a factor preventing your honeywell thermostat from working effectively.
check the thermostat batteries
Sometimes the thermostat will not be able to work properly if the batteries do not have enough power. you won’t be able to heat or cool your home if the batteries don’t have power! Fortunately, this is a fairly easy thing to fix.
all you have to do is change the batteries in the thermostat.
Look at the screen to see if the “low battery” light is flashing. As soon as your thermostat starts showing this warning, you typically have about 2 months before the power starts to fail.
then if it’s a flashing light that you noticed before you saw the “cool” light flashing, this could be the problem.
Do you have a thermostat that runs on 24 VAC instead of batteries? then you will have to check the wiring. you need to make sure you do it safely, otherwise you could get electrocuted. remember to completely shut down the system first.
When there’s no power to the thermostat, you can remove it from the wall. you will need to unscrew it from the wall to do this.
check the thermostat for the c wire to make sure everything is working properly. If you’re not entirely sure how to check your wiring, it’s best to call an electrician for help.
Do the air conditioning unit, furnace and air fans have power?
After following the steps above and noticing that the “cool” light keeps flashing after a long time, it will be crucial to take a deep breath and try to be as patient as possible. we know it can be a frustrating process trying to figure out what exactly went wrong.
Every time you check your honeywell thermostat, be sure to notice if there are any strange buzzing or clicking noises. this could give an indication that something else is wrong.
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Be sure to check your thermostat kit thoroughly. is everything getting the right amount of power it needs to function properly? look at the connectors, power supplies, and plugs.
Is everything plugged in properly and all switches turned on?
Look at all the components of your honeywell thermostat kit. Do all the doors close properly? Is there any part that has been unscrewed or loose? Does something seem to be blocking the computer or preventing it from doing its job?
then take a look at circuit breakers. Does anything seem unusual? turn the equipment off and on again. try doing this on the circuit breaker as well.
If you still can’t figure out what exactly is going wrong, you may need to take more technical steps with a voltmeter to see if any fuses have blown.
Is it necessary to change the indoor air conditioning filter?
If you need to replace your internal filter, this can throw the whole system out of control. even if everything else about your honeywell thermostat equipment works fine.
An interior filter that needs replacing can affect everything from your air quality to your thermostat and your equipment. it can even affect your energy bill!
It’s important to remember that your air conditioning filter will need to be changed every three months or so. When your air conditioning filter becomes dirty or clogged, it can affect the performance of your air conditioning unit.
the unit will have to work harder, which can cause the filter to break down faster.
a dirty filter could also affect the components of your thermostat and cause a drastic change in temperature. this can happen when the indoor coil partially freezes or if it blocks the thermostat registers.
Are the AC coils dirty?
Another component you can check is the AC coils. you should check if these have become blocked or dirty like the filter. after a couple of years, dirt can build up on the coils. this will prevent the airflow from getting through properly.
A dirty or blocked coil will not be able to cool the air or absorb heat as well as it has in the past.
By looking at the AC coils, you should know if this is the problem or not. there will be a buildup of dirt on the fins. Before cleaning your air conditioning unit, it is important to practice basic safety and turn it off.
If you want to prevent the air conditioner from clogging faster, be sure to clean the surrounding area. You’ll also need to leave enough space between the air conditioning unit and anything else you have in your home that might affect its airflow.
this will include things like plants or leaves.
reset your thermostat
Now that you’ve made sure there are no issues with all other aspects of your thermostat, you can reset it to its original factory settings. the program and preferred settings you have installed will be deleted, so remember to write them down before doing so.
You won’t want to forget them!
Reset your honeywell thermostat will vary between different models. if your particular thermostat is powered through the c-wire, you’ll need to make sure to turn it off before doing anything just to be safe.
Models that come with a menu button can be reset simply by holding down this button for several seconds. this should trigger a “reset, factory, or factory reset” message. you can find this in the “preferences” option of your thermostat if it is a different model.
Once you’ve reset your thermostat to factory settings, you’ll be able to select your preferences.
see the manual
One of the most obvious solutions, of course, is to consult the manual for your particular thermostat. this should have some information to help you determine what exactly went wrong if you can’t figure it out. there may even be tips specific to your particular honeywell model.
Don’t you have your manual anymore? As long as you know the model number of your thermostat, you should be able to find it on the honeywell website or by contacting their customer service.
call an engineer
sometimes you can try everything and still not be able to figure out what the problem is. in this case, it will be time to call in a professional engineer. If your hvac system has been working perfectly fine up until now, it might be an easy fix for them.
A professional engineer will be able to fix any damaged or faulty wiring, a blown fuse, a blocked sensor, or a faulty capacitor. They can also check to see if your hvac system’s fan motor, condenser, or compressor needs further attention.
Newer installations might have a solution as simple as making sure all cables are in the right place. a professional engineer can also help you set up the system correctly with your thermostat.
Hopefully you have now been able to resolve your issue as to why the “cool on” light is flashing on your honeywell thermostat! You should now know what exactly this light means and how you can fix it if it has been blinking for more than 5 minutes. Hopefully I’ll save money and be back up and running in no time!