What is a probable cause of high suction pressure on a heat pump?

The high suction pressure in a heat pump system is often associated with excessive refrigerant flow into the evaporator. In this context, a leaking 4-way valve can lead to the reverse flow of refrigerant or allow too much refrigerant to enter the suction line, ultimately raising the suction pressure. The 4-way valve is crucial for directing the refrigerant flow in both heating and cooling modes, and any malfunction, such as a leak, can disrupt the proper balance of refrigerant, contributing to the observed high pressure.

Understanding the role of the 4-way valve helps clarify how improper function can result in higher suction pressures, as it affects both the refrigerant's direction and its flow rate within the system. This distinction is vital for diagnosing and addressing issues within heat pump systems.