Why does my thermostat have 5 wires?

5 wire thermostat is basically a 4 wire thermostat with a “C” or “Common” wire. The newer digital thermostats for HVAC devices all require a 24V C wire connection to function. 5 wire thermostats are the most versatile thermostat; they control anything from smart air conditioners, heat pumps, furnaces, and so on.

What is the blue wire on a 5 wire thermostat?





The blue wire, or C-wire, is known as the common wire. It’s there to provide power to the thermostat. Older thermostats usually don’t have a C-wire because they either don’t need power or, if they do, they get it from a battery.

How many wires does a WIFI thermostat need?

In order to use an adapter kit, there must be a minimum of four wires currently present on your thermostat and HVAC system. The most popular adapter kit available is the Venstar Add-A-Wire (link to Amazon).

What are the terminals on a five wire thermostat?

Quote from the video:
Quote from Youtube video: Your wide terminal is your compressor. The W terminal is your heat. And your our terminal is your electrical.

Where do thermostat wires go?

The white wire underneath your thermostat connects to your heating system. It terminates at your air handler or furnace. The white wire connects to terminal W in industry-standard thermostats.

What color wire goes where on a thermostat?





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).

Where does blue wire go on Honeywell 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, like orange wires. This wire connects to terminal B on your thermostat.

Where does the blue wire go?

The blue wire from the ceiling fan gets connected to the second live wire from the ceiling. This second wire can vary in color but is most commonly red or black. This connection allows you to power your lights from the second switch.

Do I need the blue wire on a thermostat?

These wires are also called “C” wires because they’re known as the common wire. This wire allows the thermostat to connect to a power source constantly. Blue “C” wires are most common in thermostats that connect to your heat pump. This wire must connect to the B terminal on the thermostat.

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.

How do you wire a new thermostat?

Quote from the video:
Quote from Youtube video: Into the W terminal and the green wire into G or the fan tighten that one up as well. Okay. So we have the thermostat hooked up and then of course this wire goes into the wall and down to the furnace.

How do you wire a new thermostat in the wall?

Quote from the video:
Quote from Youtube video: If the hole was directly above you may already see the chain you can use this if you need to in this case we're just going to grab it and pull it right through.

Is thermostat wire usually stapled?



Generally, wires in walls are stapled to the framing. Perhaps your thermostat wire isn’t, and then you might have a chance, if it’s a straight shot.

What type of wire is used for thermostats?

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.

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 …

Is it OK to splice thermostat wire?

If you have to, you can splice the thermostat wire and generally, if the splicing has been done correctly, the thermostat’s function will not be affected. And as thermostats normally only need low-voltage power there are no safety regulations that prohibit the use of spliced thermostat wire.

Where does the black wire go on a thermostat?



This the Common Terminal, and usually, a blue or black wire is run to the transformer from this terminal to complete the circuit, and in some cases, provide power to the Thermostat. This terminal is found on thermostats designed to work with Heating Pumps and is used to power the defrost cycle on the heat pumps.

Is the common wire black or red?

Black wire: This is a hot wire that carries electricity from the power source to the first switch in a typical 3-way setup. It’s also called the “common wire” or the “line wire.” Unless the breaker is off, this black wire is always hot.