What Is The Difference Between R And RC On A Thermostat?

Do I use R or RC on thermostat?

In some systems, both the heating and cooling systems use their own signal voltage.

In these cases, the signal wire from the heating system will be connected to R or Rh , while the signal wire from the cooling system will be connected to Rc ..

Can I use RC wire as C wire?

Though it is a common notion, it may be incorrect to state that the C-wire powers the thermostat. Typically, the wires that give the power supply (usually termed as the ‘hot’ wires) are marked Rc (for cooling) and Rh (for heating). … ‘ If your system has a common wire, it will be marked ‘C’ at most times.

What do thermostat wire colors mean?

Most thermostats have a Red wire that is the power wire that usually connects to R & RC terminals of the thermostat, a Green wire that energizes the Fan relay, connected to the “G” terminal on the thermostat, a Yellow wire that energizes the outdoor unit’s contactor, (if you have air conditioning) and a white wire that …

What is W on a thermostat?

W=the heat load. On a call for heating the thermostat closes a switch between R and W, sending 24v to energize the heating circuit. … On a call for cooling the thermostat closes a switch between R and Y, sending 24v to energize the cooling circuit.

What color wire goes where on a thermostat?

If you only have a single red wire the jumper between Rh and Rc are required for some heating and cooling hybrid systems depending on your thermostat. Yellow/Y is the AC compressor. Green/G runs the fan. Blue or Black/C should be a ground and will be used by both Rh and Rc, and apparently your thermostat.

Does Nest 3rd gen need C wire?

Nest thermostats don’t typically need a C wire Nest thermostats are engineered to use very little power, less than 1 kWh/month. … So even though Nest thermostats have Wi-Fi, activity sensors, color displays and more, they typically don’t need a C wire to stay charged up.

What is jumper wire used for?

A jump wire (also known as jumper wire, or jumper) is an electrical wire, or group of them in a cable, with a connector or pin at each end (or sometimes without them – simply “tinned”), which is normally used to interconnect the components of a breadboard or other prototype or test circuit, internally or with other …

What happens if you wire a thermostat wrong?

Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself. Dual-fuel systems, a poorly located thermostat, whole-home humidifiers, or incorrect wiring can make the installation of a thermostat a longer, more frustrating, and more complicated …

Do I use RC or RH?

The RH wire refers to “red heating” which means that this is the connection you need in order to power the heating system of your air conditioning unit. … The RC wire, on the other hand, refers to “red cooling”. It’s the same with the RH wire in that it powers the thermostat. For the RC, it powers the cooling system.

What are the 5 thermostat wires?

Here is the industry standard thermostat wire color code used for most systems:White. The white wire connects to your heat.Yellow. The yellow wire connects to your compressor.Green. The green wire connects to the fan.Orange. This wire connects to your heat pump (if applicable).Red (C). … Red (H). … Blue.

How many wires should a thermostat have?

Your most basic setup on most modern units needs 4 control wires plus the fifth blue “C” wire that provides power to the thermostat. It won’t cover anything elaborate like a heat pump, but your greatest risk would be the installer uses your wire to pull the wire they actually need.

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 is 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.

What color is RC wire on thermostat?

RedThermostat Wiring Color Code ChartMarkingWire Color CodeDescriptionRcRedPower from cooling, 24 Vac transformerRhRedPower from heat, 24 Vac transformerCBlack/BlueCommon of 24 Vac transformerWWhitePrimary heat cell relay12 more rows

What if there is no C wire for thermostat?

If your current thermostat didn’t need a C-wire, it (or a wire that can be used as a C-wire) might be rolled up inside the wall.

Where do thermostat wires go?

The green wire underneath your thermostat connects to the fan of your furnace or air handler. It terminates at the air handler or furnace. The green wire connects to terminal G on your thermostat.

What is 2 wire thermostat?

If we put it simply, a 2 wire thermostat is one which has only 2 wires coming out of its backside. … 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 heating option).

What does the blue wire do on a 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. Modern thermostats are a different story.

What is the R and the RC on a thermostat?

R – 24vac (Heating transformer) Rc – 24vac (Cooling transformer) *Trade model thermostats are required to operate “dual-fuel” systems (systems that use a heat pump for the first 1 or 2 stages of heating and use a gas or oil furnace for backup / emergency heating).

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 your system has both heating and cooling functions, you’ll need to connect both the Rc and Rh terminals with a red wire. Because many thermostats come with a pre-installed thermostat jumper wire that connects these terminals, you only need one red wire, which could be the thermostat Rc wire or the Rh wire.

Why does my thermostat only have 3 wires?

If you have a heat-only system, you may notice that your thermostat has three wires—R, G, and W. In this scenario, the Power Extender Kit (PEK) is not compatible. 1) Run an additional wire to use as a C from the furnace control board to the thermostat. …