What Do The Codes Mean On A Honeywell Digital Thermostat?

Honeywell has been a prominent name in the temperature control industry for decades. With so many different thermostat manufacturers on the market today, Honeywell is a name you can trust. A digital thermostat can be overwhelming to those who are used to the old, round mercury thermostats. Depending on the system the Honeywell thermostat is controlling, there are certain codes that may appear. These codes can help you identify a problem with the system or might just be simple reminders for annual maintenance and filter replacement. It is always best to refer to the guide specific to your thermostat.

The manual for your Honeywell digital thermostat shows codes that may require attention and others that are maintenance reminders. These codes may vary from one Honeywell digital thermostat to another, but most are pretty general. Referring to your specific thermostat manual will be most helpful.

Note that RTH and TH thermostats are not always the same. Honeywell models that start with RTH are specific to retail outlets, whereas models starting with TH are more professional thermostats and are capable of more advanced setup options.

The Honeywell digital thermostat RTH8500 series can handle most HVAC systems. A 181 code is one of the most common because it is a reminder to replace the air filter. This code can be easily reset after you make sure that the filter has been replaced or inspected. To reset the filter replacement code, simply touch the "dismiss" button on the screen.

Some codes indicate a serious issue with the Honeywell digital thermostat. The code 170 gives proof of a faulty internal memory. This code is one that you may not want to find because without the internal memory, the RTH8500 will need to be replaced.

The other error code that you may hope to never find is the 173 code. This is a thermostat temperature sensor error. This error also requires replacement of the thermostat because without a temperature sensor, the thermostat cannot function.

Almost all digital thermostats have some sort of battery indication. Some may have a simple battery icon, and others may have a code. The Honeywell RTH8500 series has a 405 code indicating that the battery is getting low, and you have a month or so before anything will happen. The 407 code indicates that you have waited too long, and you are going to have problems very soon. Just as the local fire department tells you to change your batteries in your smoke detector annually, it may help to keep that same schedule for the thermostat. A battery replacement done by a professional can be pretty pricey not to mention easily preventable.

Honeywell digital thermostats are capable of handling the simplest and most complex heating and cooling systems. No matter what system you have, a Honeywell digital thermostat needs to be told how and what to control. This is done by programming the thermostat — not scheduling the times and temperatures of a day schedule but actually programming how you want the thermostat to react to your specific system. Some of this advanced programming is best handled by a heating or cooling professional who is knowledgeable about your system.

Some newer Honeywell digital thermostats are smart thermostats. These thermostats, including the T6 Pro Smart series, can be connected to your home's Wi-Fi, allowing access to your heating and cooling system through the Honeywell Home app. This app can send alerts to your phone or email. It can even send alerts to your local heating and cooling company if you set it up to do so. This will also give codes that are specific to your system and Honeywell digital thermostat.

Honeywell digital thermostats have come a long way in helping you stay on top of your heating and cooling system with code reminders and connectivity, which is definitely more than the old, round-face mercury thermostats of yesterday.