A small solenoid pilot valve shifts a slide inside the main body using system pressure difference, so the valve only changes over while the compressor runs. Most brands energize the solenoid in cooling and a few in heating, which is why thermostats have an O or B setting. A valve stuck midway, or leaking hot gas into the suction side, shows as a hot suction line and poor capacity in both modes.
Reversing valve won't shift into heat, coil's getting 24 volts, so tap it with the compressor running and see if it moves.
A reversing valve stuck midway leaves the suction line warm in both modes; feel all four lines before replacing one.
Also heard as
- 4-way valve
- four-way valve
- RV
- changeover valve
Related terms
Heat pump
A refrigeration system that can reverse its flow to move heat indoors in winter as well as outdoors in summer.
Defrost
A cycle that melts frost off a heat pump's outdoor coil or a refrigerated evaporator so it can keep moving heat.
High side
The high-pressure half of a refrigeration system, from compressor discharge through condenser to the metering device.