HVAC Hoses & Valves

Climate Control


High- and low-pressure refrigerant hoses connect the main parts of the air conditioning system together. An orifice tube or thermostatic expansion valve regulates refrigerant flow in the A/C system. Service fittings provide connections for service equipment so that system pressures can be checked and refrigerant may be recovered and recycled. Heater hoses connect the engine's cooling system to the heater core. A heater control valve may be located in one of the heater hoses to regulate coolant flow to the heater core.


Refrigerant hoses provide a path for refrigerant and refrigerant oil between the key components of the A/C system. The orifice tube (most common) or thermostatic expansion valve ensures proper refrigerant flow for different operating conditions. Service fittings, unique for each type of refrigerant, enable the connection of service equipment and reduce the chances of mixing different types of refrigerant. Heater hoses provide a supply and return path for warm engine coolant circulating in the heater core. The heater control valve may help control heater output by opening and closing coolant flow to the heater core.

Maintenance Tips/Suggestions

Hoses and valves should be inspected periodically for condition and to make sure all connections are secure. Chafed, cut or damaged hoses should be replaced. Poor A/C cooling may indicate problems with the orifice or expansion valve. Insufficient heat, or heat that can't be turned off may indicate a problem with the heater control valve. When in doubt, have your car's HVAC system evaluated by a qualified professional.

vehicle diagram