Table of Contents
What color wires go where on a furnace?
This is the most typical thermostat wiring style, and it applies to systems that regulate both heat and air conditioning. The wires are typically arranged as follows: red for 24-volt hot, white for heat, yellow for cooling, green for the fan, and blue for common (although the common wire may be a different color).
Which thermostat wire controls the furnace?
The W wire is connected to your heating system. If your thermostat controls your heat, you will have a white wire. The Y wire is yellow and connects to your air conditioning compressor. The G wire is green and connects to the fan.
What happens if you wire a thermostat wrong?
Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.
What color is the C wire on a thermostat?
Blue wires are also called “C” wires because they are the Common wire. C wires are necessary for any “smart” thermostat that needs to be connected to a power source 24/7, regardless of your heat pump type.
What are the 4 wires on a thermostat?
4 Wire Thermostat Wiring (Heat Pumps, HVAC) Red wire for power (24V). White wire for heating (connected to W or W1 terminal). Green wire for fans. Blue or yellow wire for cooling (connected to Y).
What are the four wires in a thermostat?
In general, the heating wire (often white), goes into the “W” port, the cooling wire (often yellow), goes into the “Y” port, the wire that sends power from the HVAC system to the thermostat (often red), goes into the “R” port, the fan wire (often green), goes into the “G” port, and the common wire (often blue), which.
What happens if you wire a 2 wire thermostat wrong?
If you get it wrong, the heat will run continuously. Once you have them paired, attach one pair to “24VAC” (R) and the other to “Heat call” (W) on the thermostat. Doesn’t matter which one, since the thermostat just shorts them either way.
Can I use a digital thermostat with 2 wires?
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’.
Why does my thermostat only have 2 wires?
If your heating system has only two wires, the job of the thermostat is simple. All it has to do is turn the heat or the cooling on and off. There’s also no thermostat blue wire, or common wire, to power the thermostat, so it has to operate on its own, either using batteries or mechanical temperature detection.
Does thermostat get power from furnace?
Most room thermostats on heating and cooling systems receive their 24V AC electrical power from a low voltage transformer that itself is usually found at the boiler or furnace (blue arrow in our photo at left).
Does thermostat need jumper wire?
Nest thermostats don’t use jumper wires Putting more than one wire into a Nest thermostat connector can damage your system and your thermostat. Instead of using jumper wires, Nest Learning Thermostats use an internal jumper between the Rh and Rc connectors.
Should my thermostat be on E or F?
The thermostat fan operation switch, labeled FUEL SWITCH in the diagram below, is factory-set in the “F” position. This is the correct setting for most systems. The “E” setting will allow the fan to turn on immediately with the heating or cooling in a system where the G terminal is connected.
What is the common wire on a thermostat?
WHAT IS A C-WIRE? A C-wire, or a common wire, runs from your low voltage heating system (24v) and carries continuous power to your thermostat. In today’s electric market, most newer heating and cooling systems have C-wires, which guarantees compatibility for the installation of all smart thermostats.
What gauge wire is thermostat wire?
The most common thermostat cabling is 18/5 (18 gauge, 5 conductor), because 5 conductors typically offer enough functions for a modern thermostat/low voltage device.
Why is there a jumper between R and RC?
Effectively there isn’t a second RH wire, although there is an RH terminal. However, the heating still needs to be controlled, so a wire known as a jumper is connected between the RC and the RH terminals so that power gets to the heating control part of the thermostat.
Do I need a jumper from R to RC?
If you have a wire in the R terminal, and no wire in the RC terminal, use the jumper selector switch, the jumper plug, or a small jumper wire to connect the R and Rc terminals. If you have a wire in the R terminal, and another wire (not a jumper) in the RC terminal, you will not need to connect the R and RC terminals.
What is o’b wire on thermostat?
O, B, O/B: These wires are responsible for switching the changeover valve in a heat pump system. The O wire reverses the valve from heating to cooling, and the B wire switches the valve from cooling to heating.
What is the blue C wire on a thermostat?
The Blue or C Wire C wires or varying colors apply to every thermostat, but blue C wires belong to thermostats attached to a heat pump. Blue wires are for heat pumps. This wire connects to terminal B on your thermostat.
