Honeywell Thermostat Short Cycling [SOLVED]

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Is your Honeywell thermostat short cycling? There are a few things that can make your furnace and air conditioner system ‘short cycle’; and these range from simple to more complicated issues.

If your Honeywell thermostat seems to be short cycling, it could be a sign of an issue with your furnace or air conditioner system. In Many cases, a dirty air filter will cause your furnace or air conditioner to short cycle.

Things that can cause a Honeywell system to short cycle include:

  1. Dirty Flame Sensors
  2. Oversized AC system
  3. A furnace that is overheating

1.      Dirty furnace flame sensors

A flame sensor is a small device in your furnace that is designed to prevent the leaking of gas into your home.

It works by detecting the presence of flames 5 to 10 seconds after the gas valve opens. If no flames are detected, the sensor will close the gas valve, preventing possible gas poisoning or fire in your home.

However, over time, a flame sensor can become dirty and sooty. When this happens, it will not be able to properly detect flames when the furnace is turned on. This could be the reason for your Honeywell thermostat’s short cycling.

In order to resolve the dirty flame sensor issue, you’ll need to remove the flame sensor from your system and clean it. This is an easy job to do. See the video below.

However, there are times a flame sensor could be permanently damaged. In that case, you’ll notice that even after cleaning it, the short cycling problem won’t go away. If the problem doesn’t go away after cleaning the sensor, you can order one online.

A flame sensor is one of those spares of a furnace that are cheap to replace.

2. Oversized Furnace/ AC system

Another thing that can cause thermostats to short cycle is an oversized HVAC system.  When you have an oversized furnace for your home, it will cool your home too quickly and unevenly.

This will cause your furnace to turn off and on quickly in an attempt to reach the set temperature.

3. A furnace that is overheating

Another common cause for the short cycling of your HVAC system is an overheating furnace. Overheating is mainly caused by restricted airflow into the heat exchanger. 

Restricted airflow into your furnace/HVAC system comes about because of a clogged air filter or blocked return air vents. You must ensure that your filters are changed or cleaned on time (for the washables). 

Also, when your thermostat seems to be short cycling, check that no objects are blocking the return vents.  

When vents are obstructed, air getting into your furnace will be limited so the heat exchanger will heat up too quickly causing the high limit switch to sense this and eventually turn off the system.  

But remember, this can happen before the set temperature is reached. Because of that, the furnace will try running again. This happens too quickly, resulting in the system to short cycle. 

The best solution to prevent overheating of your HVAC system is to have regular maintenance. But if you do experience furnace short cycling from overheating, ensure that return vents are not blocked by objects and that your air filters are clean.

How does a dirty filter cause your cooling/ heating system to short cycle?

An air filter in your furnace or air conditioner helps to trap dust and other unwanted substances from getting into your system, which would otherwise cause problems with the normal working of your HVAC system.

If filters become dirty and clogged, they will restrict airflow into your furnace and when this happens, overheating can occur in your system.

Because your system is built with a safety mechanism, it will automatically shut down the furnace when overheating takes place. This can occur before the set temperature is reached.

When the furnace cools down again, it will start to try and heat to the set temperature. And that can happen too quickly could actually be the reason for short cycling.

 To prevent short cycling from clogged or dirty air filters, you need to regularly change or wash air filters.

How often should I change air filters?

How often to change your furnace air filters depends on a few factors. Some of the factors include the quality of your surrounding air, the number of hours the filter has served in your home, whether you keep pets or not, and so on.

Luckily there are HVAC systems that come with the filter checking led indicators. These indicators will tell you when your filter is due for replacement or cleaning depending on the number of hours your filter has worked.

As a rule of thumb, if your system doesn’t have this feature, replacing your filter at least once in a couple of months is recommended.


Is HVAC Short Cycling an Emergency?

Short cycling is a sign of an underlying problem with your air conditioner/HVAC system, and if you don’t address that problem, it could cause major damage to your system. However, it’s also worth noting that short cycling can be caused by a refrigerant leak or an electrical problem in your system. These are much more serious issues that require professional help to repair.

While you may be able to postpone it a day or so without causing too much trouble, you should call your AC repair professionals as soon as possible to have them check out your system and find out what’s causing the short cycling.

If they do find a serious problem and recommend an action to take, don’t hesitate; doing so can save you costly repair bills in the long run by preventing further damage.

Should I turn my furnace off if it is short cycling?

If your furnace is short cycling, you should turn it off immediately.

Short cycling could damage your AC compressor or your entire equipment if the problem is not addressed.

If the problem is a result of your furnace overheating, it may need to be cleaned, or the airflow may be restricted because of a dirty filter or closed registers.

 If you can’t figure out what is causing your system to short cycle, you will have to call a professional to check it out.

Once you have determined what the problem is, get it fixed right away, as short cycling in your HVAC system particularly your furnace can lead to problems such as:

·         Burning out the blower motor

·         Failing heat exchanger

·         Reduced energy efficiency

Why Does My Honeywell thermostat keep restarting?

Your thermostat batteries could be the reason your Honeywell thermostat keeps restarting.  Has it been over 10 months since you replaced your thermostat batteries? If so, then it’s high time you replace your thermostat batteries.

Honeywell thermostats are designed to warn you when batteries become low; about two months prior to completely dying out. However, you might have missed the battery warning message if you were away from home.

Don’t worry, there are still other signs of low batteries in a thermostat, including a faint display, your screen going completely blank, and a few others.

Final Thought on Honeywell Thermostat Short Cycling

We hope that this article has been helpful. So, whenever your Honeywell thermostat seems to be short-cycling, always check your air filter first, then your flame sensor (for your furnace.)

Otherwise, if everything seems to be in order but your system continues to short cycle, then call HVAC professionals to come and troubleshoot any issues. Thanks for reading.

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