Asked by: Maureen Harkin
asked in category: General Last Updated: 22nd January, 2020

How do I know if my heat pump is O or B?

On many other thermostats, the O wire is typically connected to a terminal marked W on one side and O or O/B on the other side; the W is for use with a conventional system (furnace) while O/B is for use with a heat pump.

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Simply so, is my heat pump O or B?

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.

Also Know, what color is C wire? Here are common uses for wire colors: Blue or Black – C – Common wire, may be unused by your existing thermostat. Enables continuous power flow from the Red wire. Red – R – 24VAC power from the furnace's transformer.

Also, what does o'b mean on thermostat?

The O/B terminal is for heat pump systems and is used for the reversing valve. When the "O" option/position is selected the reversing valve defaults to the heating mode. If the "B" option/position is selected the reversing valve defaults to the cooling mode.

What is the O B Wire?

A wire labeled O, B, or O/B is used to control whether a heat pump is in heating or cooling mode. However, on some thermostats, a wire labeled B is the common wire C. In most cases, the common wire is labeled C.

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