Four-way valve in the refrigerant circuit: how it reverses heating and cooling

The four-way valve allows a reversible heat pump to change the direction of the refrigerant cycle.

In heating

The indoor exchanger acts as a condenser and the outdoor one as an evaporator.

In cooling

The roles are reversed.

Defrost

The same principle is used temporarily during the defrosting of the outdoor exchanger.

Important

Incomplete movement of the valve can cause low efficiency or problematic defrosting.