What is the purpose of the C terminal in a thermostat?
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 is the C terminal on the furnace board?
What is a C-Wire? A common wire (C-Wire) provides Wi-Fi thermostats continuous power by connecting it to a heating and cooling system (e.g. furnace). C-Wires are required on most Honeywell Wi-Fi thermostats, with the exception of the Smart Round Thermostat (formerly known as the Lyric Round).
What does the OB terminal on a heat pump thermostat control?
The O/B terminal on the subbase of your thermostat, controls the reversing valve in your heat pump systems outdoor unit. The reversing valve is the valve that switches the heat pump between heat mode and cool mode.
What terminals close when thermostat calls for heat?
W/B: The W/B terminal controls the heat relay or valve. When the thermostat calls for heat, a signal is sent to power up the furnace and the blower fan or the boiler, heating your home.
Can I use the G wire for the C wire?
Option #3: Use a G-Wire as a C-Wire
If there is no hidden C-wire, you can use a G-wire instead. However, you will not be able to use your fan independently when the heating or cooling isn’t running. Also, many HVAC systems are incompatible with this solution, including: HVAC systems using electric heat.
Is RC and C wire the same?
Hi there! The C and Rc wires are not the same. To install this thermostat you should follow the exact same wiring of the previous thermostat.
Where does C wire go in furnace?
If your system has a C-wire, it might be in use or just tucked away behind your current thermostat. If your system doesn’t have a C-wire, you’ll need to run a new cable from your furnace to your thermostat to install most of the modern smart thermostat models.
How do I know if my C wire is connected to my furnace?
If there is a wire connected to the C terminal at the HVAC control board:
- Note its color.
- Check if there are any wires tucked behind the back of the thermostat with the same color.
- If there is a matching wire, that should be your C wire.
How many wires can be connected to the C terminal at the furnace?
Two wires per terminal in HVAC work is common (though not usually correct), while 3 or more will tend to use a pigtail.
What color is C wire?
Blue wires
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.
Do I need a jumper from R to RC?
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. See our Basic Wiring article for more info here.
Does your heat pump use an O wire or B wire?
If you have a heat pump and your thermostat doesn’t have a separate wire labeled O, then the wire labeled B should be connected to the Nest thermostat’s O/B connector.
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.
Should my thermostat be set to O or B?
Check your configuration. Most commonly, O/B is energized in Cooling (O on cool). For Rheem or Ruud brand heat pumps, the O/B must energize on heating (B on Heat).
How many wires do you need for a heat pump?
8 wires
In heat pump system, there are at least 8 wires that need to be connected to the thermostat for proper operation.
Do heat pumps need C 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 color are thermostat wires?
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).
Does a heat pump require a special thermostat?
You need a special thermostat for a heat pump because it needs to be able to communicate with the reversing valve when changing from heating to cooling. Heat pumps rely on outside air and electricity. Heat pump thermostats will typically have a fifth wire explicitly for the reversing valve.
Can you use a Honeywell thermostat with a heat pump?
Honeywell RTH5100B 1025 Deluxe Manual Thermostat
The set temperature is maintained even when the thermostat restarts after a power outage. It is compatible with Works on all central heating and cooling systems including heat pumps without an auxiliary heat source.
At what temperature does a heat pump switch to emergency heat?
The Emergency Heat or Auxiliary Heat setting is the second stage of your heating system that is used when the temperature is too low for the heat pump to be able to remove heat from outside, typically below 35 degrees Fahrenheit.
