What Does the Flashing Snowflake on Your Thermostat Mean?

Written by David Lewis
5 Min read
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Table of contents

If you’re being greeted by the sign of a blinking snowflake on your thermostat, don’t panic. It isn’t a sign that you’ll soon be plunged into the next Ice Age. It simply means your system is going into delay mode.

Okay, so what does that mean?

In this blog, we’ll analyze some leading thermostat brands, tell you why you’re getting that flashing snowflake, and what it means for your system.

But, why don’t we start by telling you more about the snowflake?

So, why is the snowflake on my thermostat blinking?

As we said above, the reason you’re seeing that flashing snowflake on your thermostat is probably to indicate it’s going into (or is already in) delay mode or a delay cycle.

What happens when my thermostat is in delay mode?

Delay mode is, essentially, your AC or furnace’s defense mechanism against a harmful process known as short cycling. Put simply, this is when your system tries to turn on and off too quickly.

Typically, your system will stay in delay mode for up to 5 minutes to break the cycle and allow for recovery in both your room temp and its own functionality.

But, while delay mode is normal and a measure put in place to protect your AC (and your wallet), it’s also a good indicator of one or two slightly larger underlying issues.

So, now we know why the snowflake is flashing on your thermostat, let’s take a look at what that means for your system going forward.

What is short cycling and how does it happen?

We all know that our air conditioners and furnaces temper the air inside your home or office against what’s happening outside. So when it’s too hot they cool us down and vice versa in cold conditions – that’s why we buy them, right?

Generally, to temper your building against these external conditions, your system will click on and off or ‘cycle’ at set times or when the inside temperature hits a certain reading. 

When we experience extreme heat or cold, our systems are made to work harder to ensure those inside conditions remain mild. Usually, this cycling occurs up to every 20 minutes, but in those adverse elements, the cycling time can be as little as half that time.

Short cycling is when your system is turning on and off faster than it should, which causes your HVAC to work exceptionally hard. This excess strain can cause your precious system to stop working entirely.

So, what are the main causes of short cycling?

There can be any number of reasons why your system is in delay mode as a result of preventing a short cycle and now showing you that blinking snowflake.

But whatever the reason, it needs taking care of. Or you risk breaking your AC. Let’s take a look at 5 common causes of short cycling.

  1. Incorrectly sized AC or furnace
  2. Repairs needed
  3. Your system needs a clean
  4. Issues with your thermostat
  5. Your unit is incorrectly placed

Incorrect sizing

If your HVAC is too big or too small it will be heating or cooling your space too quickly. This will cause your system to enter a short cycle as the standard processes aren’t giving it the results it wants. Unfortunately, only a professional contractor will be able to tell you if your system is the wrong size.

Repairs needed

There could be an internal issue with your HVAC unit. From the flame sensor to the condensate switch many high-functioning elements can cause cycling issues. Or, without casting dispersions about your children or pets, someone may have just bashed into it while playing. Again this is one for the pros to sort.

Your system needs a scrub

With important pieces of equipment like ACs and furnaces, it’s important to stay up to date with general appliance maintenance. Dirty or dusty filters and sensors can cause warnings. If you have an exterior unit, it’s also always worth keeping the area around it clear.

Thermostat problems

If, for example, there’s a problem with your Honeywell thermostat, it can cause your system to enter a short cycle. On the other hand, if your thermostat is located too close to a heat or cold source, its sensors can be fooled into thinking your space is hotter or cooler than it actually is. 

Incorrectly placed HVAC

This is more of a problem if you have an interior unit. But, much the same as your sensor being improperly placed, if your unit is too close to a wall or window this can cause it to work harder too. Energy can escape through windows, whereas walls will just bounce the energy back at the vent.

Does the flashing snowflake mean the same thing on different brands?

Honeywell

If your Honeywell thermostat has a blinking snowflake it means your system is in delay mode. Give it five minutes and it should cycle on again. However, as we said above, it’s also a sign that a larger issue needs to be fixed.

White-Rodgers and Emerson

When your White Rodgers thermostat is blinking, it’s usually a sign of the compressor lockout feature or it’s in lockout mode. Again, this is a measure to prevent short cycling. The same goes for an Emerson thermostat showing a flashing snowflake.

Luxpro

While, so far, this pulsating symbol has meant a problem, when your Luxpro thermostat is displaying a flashing snowflake it’s actually an indicator of normal service.

In summary

So, generally speaking, if there’s a flashing snowflake on your thermostat it’s your system trying to save you some money and energy (Luxpro units excluded).

But, it’s also a pretty strong indicator that there’s something untoward happening in your HVAC system. We’d recommend getting a professional to give your unit a once-over just to be sure.

What does resetting a thermostat do?

Resetting your thermostat turns it off and essentially returns it to factory settings. You will then need to re-upload your preferred temperature or time settings.

What do I do if my AC isn't blowing cold air?

This could mean that your system is in need of a clean. dust and ice can build up in your AC system so it's important to keep it clear. It's worth having professionals check over your system yearly.

Does snowflake mean heating or cooling?

Usually, the snowflake displayed on your HVAC thermostat means your machine is entering (or in) a cooling cycle as the temperature in your space has risen above a pre-set level.

How do I reset my thermostat?

Switch the thermostat to the "off" setting and locate the breaker switch for the unit. Turn off the breaker and wait 30 seconds before switching the breaker and thermostat back on.

Appliances made simple. 

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