The Google Nest Thermostat (Gen 3) is a very impressive product that offers an easy way to monitor your home’s heating and cooling needs. Remove the motherboard of the old thermostat completely, and secure the wires. You don’t want them to hide deep inside the wall. This 4 wire thermostat wiring is for simple, single stage heat pumps. See 5-wire and other options for more complex heat pump systems. 5 Wire Thermostat Wiring

Note that only 24-volt wiring is covered: We do not cover 110/240-volt thermostat wiring and millivolt thermostat wiring issues. Compared to Honeywell’s non-programmable thermostat, this LuxPro Digital Thermostat is perfect for in-floor radiant heat systems and even fireplaces. Its digital display with yellow light and slim design will have you covered.

Thermostat Wire Colors Are Standardized

Ensure that you know where the wires go. Ideally, the red or “R” wire will go to the “R” terminal while the white wire will go to the “W1” or “Rh” terminal. Take a photo of the connection to be on the safer side.

While reading the install manual for Honeywell RTH6580WF (old unit: Radio Thermostat CT32), I learned not to look at wires using the colors but by the terminals to which they are connected. We’ll cover the basics here that are fully detailed in our exclusive guide, C-Wire Issue: What If I Don’t Have a C-Wire. The C wire delivers constant power to the thermostat, so that it constantly monitors the indoor temperature and other climate features. The purpose of this is to create the most precise indoor comfort.

How to Wire a 2-Wire Thermostat to a 4-Wire System

When 4 wire thermostat wiring plus a C-wire is required, then you need 5 wire thermostat wiring. It’s pretty simple. The key is to use a wire not used for another purpose as the common wire, or C-wire. Put the new motherboard in the place of the old one, and pull the wires through the 3 wire thermostat.

To reconnect the wire, simply put the wire on the right terminal and tighten down the set screw. Pull a wire a bit to make sure the wire is properly fixed. There are several solutions to your problem. Some might just want to install a new 6 or 8 wire thermostat wire to your thermostat. (the proper but usually more difficult way) This might mean relocating your thermostat. Or they might bring a product like the one that you have, to wirelessly connect the thermostat to the furnace, and then use the builder installed 2 wires to power the thermostat.

How a 2-Wire Thermostat Works

Two-wire thermostats are single-pole devices that can handle the heating system without hassle. The single-pole thermostats can flow the current in one direction and have the red and white colors in circuitry. These thermostats (2-wire) cannot be sued for cooling systems such as Air conditioners, HVAC systems with cooling options, and even multistage systems. The Nest 3rd Gen thermostat has 10 terminals, say Rh, Rc, W1, W2(aux) Y1, Y2, O/B, G, C, etc. You just need to connect ‘red’ wire from the furnace to Rh and ‘white’ wire to W1. These 2 connections will set the Nest thermostat as a ‘smart 2 wire thermostat’ taking care of your home heating ‘smartly’.

Keep in Mind: If you are having a single-stage heat only system (like a furnace) in your home, you can use any kind of thermostat that supports single stage systems. For example, you can use the Nest 3rd Gen smart thermostat or Honeywell RTH9585 wifi thermostat for your ‘heat only’ single-stage system. In this case, you just need to connect the ‘R’ and ‘W’ terminals of the thermostats and leave all other terminals intact without making any connection. Trial and error:There are a few instances in which you might have to use a trial and error methodology on advanced heat pump systems. This is most common when you don’t know what components and features your system has. But fear not– we give you alternate wiring options for those systems. They are found below 2 Wire Thermostat Wiring

Honeywell Thermostat Wiring: How to Replace a 2-Wire Thermostat

There are two terminals for the white wire in a thermostat. Essentially, you can either be talking about the “W1” or W2” wire. The white wire is typically found in a gas furnace thermostat. While the “W” wire goes directly to the heating source, e.g. furnace or heat pump, “W2” is designed for 2-stage heating. Put on the control panel, and test if your boiler or hot water heater connected to the 3-wire thermometer functions properly. White wires are for heating. You will find them in gas furnace thermostats, for example, but won’t find them in air conditioner thermostats. The 2 wire thermostat for line voltage systems is technically known as single pole thermostat (and the 4 wire version is known as double pole thermostats). When it comes to low voltage systems, a 2 wire thermostat is usually known as a “heat only thermostat” and is used for systems like a gas furnace (with only a heating option). A 2 wire thermostat can not be used for HVAC systems with a cooling option, or heating systems with multi stages or a heat pump. Wiring & Color Code In recent years, thermostats have become more and more high-tech. There are now several different types of thermostats on the market, from the standard programmable thermostat to the more advanced Wi-Fi thermostat. If you’re looking for a high-tech thermostat that is easy to use and doesn’t require any programming, then a 2-wire smart thermostat may be the perfect option for you.