More than a decade ago, I developed a fixation with thermostats. I’ve installed and repaired so many thermostats throughout my career that I’m embarrassed to admit that I made a mistake the last time I purchased one. Without recognizing it, I purchased a Honeywell Programmable Thermostat without realizing I needed a C Wire. I found myself in a difficult situation. Many thermostats nowadays are equipped with WiFi capabilities. This indicates that the thermostat can connect to your WiFi network, allowing you to control the temperature using an app on your smartphone or tablet. When it comes to configuring these thermostats, one of the most challenging chores is configuring the WiFi. However, it is not insurmountably difficult!
First and foremost, let us define what a c wire is…
A “C” wire is sometimes referred to as a “common wire” in some situations. Known as the common wire, this is the low-voltage power wire that WiFi thermostats require for their advanced capabilities to function properly. Unfortunately, many older homes do not have a C wire connected because the earlier thermostat models did not require one to function properly.
As you can see, old-style thermostats were straightforward gadgets. They did not need a continuous power source. While modern thermostat models frequently feature backlit displays and WiFi connectivity, these features require a constant electricity supply.
There is a good chance that you will not have a C-wire, which is an alternating current common wire. There are numerous older thermostats still in use in many homes that were not designed with WiFi functionality in mind; hence, they did not require the installation of a C-wire.
Backlights, geolocation capabilities, and WiFi are all features of today’s new thermostats, and to have these features. Numerous clients also inquire whether it is possible to install their WiFi thermostat with no C wire while still benefiting from its superior capabilities. Unfortunately, this is not possible.
Do Honeywell Thermostats Work Without A C Wire?
Except for the Smart Round Thermostat, practically all Honeywell WiFi thermostats require a C wire to function (earlier called Lyric Round). The C wire is an abbreviation for the common wire, which connects the WiFi thermostat to the heating and cooling systems to give steady power to the intelligent thermostat.
If you need to install a Honeywell Thermostat quickly and do not have access to a C Wire, all you have to do is install a C Wire adapter available from most hardware stores. This is a quick and simple remedy that is both inexpensive and long-lasting. I was able to resolve my issue using a C Wire adaptor.
Examining your thermostat is the quickest and most straightforward method of determining whether or not there is a common wire. Remove the thermostat from the wall and examine the cables that connect it to the other components of the system.
There should be a terminal with the letter “C” on it. This terminal is operational if and only if a wire is connected. You can install your new thermostat in the same manner as before.
Don’t be alarmed if you don’t see a wire attached to the “C” connector; it’s possible that you still have one. The common wire is sometimes hidden in the wall behind the thermostat, which is a problem.
Examine your furnace to see if there is a concealed “C” wire in your system. A common wire may be lurking in the wall if you discover it here, so be cautious if you discover one here.
Voltage Requirement For Honeywell Thermostat
Honeywell’s thermostats are available with a line-voltage system (240 or 120 volts) and a low-voltage system (24 volts) installed. The voltage commonly found in a central cooling and heating system is 24 volts in most cases (24 VAC).
If you have an old thermostat placed in your system, you must first determine if you require low voltage or line voltage to replace it. Whether it says 120 VAC or 240 VAC, your system will require a line voltage system rather than a low voltage system.
How To Install Honeywell Thermostat With No C Wire?
A suitable plug-in transformer, such as the OhmKat Professional, will be required to install a Honeywell Thermostat that does not require a C wire to function. This transformer is ideal for smart thermostats because it was designed for all C wire applications and has a standard outlet with a thirty-foot-long wire with a split assembly for easy installation. It also has a standard outlet with a thirty-foot-long wire with a split assembly for easy installation. It meets the Honeywell voltage standards (24 volts), allowing you to power the smart thermostat safely.
Honeywell WiFi Thermostats that are more recent in design contain a C-wire adaptor as part of the box. The following instructions will guide you through the process of installing these adapters.
Step 1 – Get the C-Wire Adapter
As previously stated, using a C-wire adapter to connect the C-wire to your thermostat is the most efficient method of doing so. As a certified HVAC professional, I would recommend the Ohmkat C Wire Adapter for this particular application. What is it about it that I recommend?
What is it about it that I recommend?
- It came with a lifetime warranty and was designed exclusively with the Honeywell Thermostat in mind.
- I’ve been using it personally for several months now.
- It is manufactured in the United States.
However, before you take my word for it, I want you to understand why they can provide a lifetime guarantee on it. It’s quite impossible to cause any damage to this machine. With the help of a feature known as the One-Touch Power Test, we may quickly determine whether or not it is supplying power without using any extra instruments. Furthermore, it is short-circuited proof, making it an extremely safe piece of equipment. Because it is externally wired and attached to your outlet, you must keep it safe.
Step 2 – Check the Honeywell Thermostat Terminals
After removing the panel from your Honeywell thermostat, you’ll be able to see the various terminals on the device. These may differ based on the type of thermostat you are using, but the basic layout is the same for all of them. The primary terminals with which we need to be concerned are as follows:
- R terminal – This is the one that is utilized to supply power.
- G terminal – This is where the fan control is located.
It is the Y1 terminal that regulates the flow of water through your cooling loop.
It is the W1 terminal that regulates the heating loop of your home or business.
In this case, the Rh terminal is only to power the thermostat, effectively completing the circuit for the thermostat.
The most important thing to remember is to make sure that your furnace’s circuit breaker is turned off before you begin the installation process!
It is necessary to check that your furnace is equipped with a C terminal before you may connect a C-wire to the furnace. A 24V transformer can be installed in your furnace if it already has a C terminal. This will make the furnace compatible with a C-wire connection.
Step 3 – Make Necessary Connections to the Honeywell Thermostat
We may now begin the process of installing our Honeywell thermostat. Before you begin any wiring, make sure that the electricity to your HVAC system has been switched off for your protection.
Be sure to note the wiring that is already in place before you begin removing your old thermostat from its mounting bracket. This step is critical because you will need to make certain that the identical wires are connected to the corresponding terminals on your new Honeywell thermostat when it is installed. As a result, it is a good idea to photograph the wiring of your old thermostat before removing it.
To connect a heating system:
- Connect the correct wire to W1, which will form a link to your furnace. If you do not have a heating system, you will need to use a different wire.
- If you have a cooling system, connect a wire to the Y1 pin on the motherboard.
- When connecting a fan, use the G terminal to connect it to the computer.
Step 4 – Connect the Adapter to the Honeywell Thermostat
As specified in the previous step, you must ensure that the connections are precisely the same as they were in the thermostat that you removed, except the following:
- It would be best to detach the R wire connected to the thermostat previously.
- Take one wire from the adapter and attach it to the R terminal instead of the R terminal on the computer. You must take the second wire from the adapter and attach it to the C terminal on the computer’s motherboard.
The result will be identical no matter which of the two wires you connect to the R or C terminal. Check to see that all wires are connected to their corresponding terminals properly and securely. A better practice is to ensure that the copper portion of the wire is not exposed outside of the terminal when the wire is connected. Make sure that only the insulation of all wires is visible on the outside of the terminal box.
Essentially, we have created a completed circuit in which power can be delivered from the R wire to the C wire, allowing the thermostat to operate without interruption. As a result, your thermostat is now powered by the C wire, whereas previously, it was powered by your HVAC system.
Step 5 – Put the Thermostat Back On
It is possible to turn the thermostat back on when all essential connections have been made. Make sure that the power is still turned off until you have finished resetting the thermostat to its original setting. This is done to ensure that no short-circuiting occurs and that the gadget is not damaged.
Because all of the wiring completed here is low voltage wire, there isn’t anything, in particular, to be concerned about. However, it is usually preferable to turn off the electricity as a precaution. Once the top of the thermostat has been firmly reinstalled, you will be able to turn it on.
Step 6 – Power ON Your Thermostat
You may now plug your Honeywell thermostat into a regular power outlet and turn on your Honeywell thermostat as needed. If the thermostat begins to blink, it means that all of the wirings have been completed correctly, and we are ready to proceed with the installation and configuration.
You only require the usage of a C wire adapter to complete the installation of your Honeywell thermostat fast and efficiently. If you want to conceal the wires coming from your adaptor, you can run them through your wall and into your room. If your walls or ceiling are only partially done, this will be a lot easier. In either case, if you are planning to do this, make sure to verify the local regulations and ordinances in your area to ensure that no violations are being done.
Step 7
Some systems will not power on if the cover is not completely closed on the system. As a result, be certain that your furnace or heating system is completely shut down before closing the lid.
Conclusion
It would be beneficial if you noted that your WiFi thermostat unless otherwise specified, requires a C wire, as the C wire assures a consistent supply of electricity to your HVAC system. On the other hand, the Honeywell Thermostat can be installed without the use of a C wire. It is not nearly as difficult as it appears. Follow the procedures outlined above!
Frequently Asked Questions
What is the K terminal on Honeywell Thermostat?
The K terminal is a Honeywell-exclusive terminal found on Honeywell Thermostats when used in conjunction with the Wire Saver module. It serves as a splitter, allowing the connecting of the G wire and the Y1 wire to it, allowing systems to be connected without using a C-wire in some instances. However, it is incompatible with a small number of systems.
Are R and Rh the same?
In systems with a single power source, you would connect wires from the heating and cooling sections to R, but in systems with two distinct sources of power, you would link wires from the heating and cooling sections to Rh and Rc, respectively. On the other hand, most new smart thermostats have Rc and Rh terminals that are jumpered together, allowing you to attach a single R wire to either the Rc or Rh terminal.
