What are the symptoms of a stuck expansion valve?

Symptoms of a bad expansion valve

• Car AC system isn’t cooling enough or won’t cool at all.
• High side pressure is high.
• Air coming from vents is frosty.
• AC blows cold, then hot.
• AC kicks on and then immediately kicks off.
• Airflow drops dramatically from vents.

What can cause a stuck expansion valve?

THE PROBLEM. The expansion valve is an advanced and fragile device. As it operates under high pressures and is temperature sensitive, improper working conditions as well as impurities inside the loop can cause it to malfunction. If the expansion valve is stuck open or clogged, the A/C system will not cool properly.

Can an expansion valve stuck open?

As the expansion valve operates under high pressures and is temperature sensitive, improper working conditions, as well as impurities inside the loop, can cause its deregulation and malfunction. If the expansion valve is stuck open or clogged, the AC system won’t cool properly.

How do you unstick a stuck expansion valve?

Place the bulb into hot water. This should cause the expansion valve to open allowing more refrigerant to pass through the TXV into the coil. Suction pressure should rise, and super heat should drop. Opening of the valve should be relatively quick.

What does a bad TXV do?

Valve blockage A plugged TXV will underfeed the evaporator and produce symptoms that include the evaporator operating under a vacuum or very low pressure. A plugged valve will not respond to a superheat decrease or will suddenly open up if superheat is adjusted downwards.

Why do thermal expansion valves go bad?

What causes a TXV valve to go bad? Thermal expansion valves work under extremely high pressure and temperatures which tend to fluctuate up and down. The valve’s parts are bound to wear down over time from the fluctuations. A TXV valve can fail if it’s too open and overfeeding or too closed (underfeeding).

How do you test an electronic expansion valve?

Perform an “Closed Valve Test” per Service Facts instructions. Remove the stepper motor from the EEV 15 seconds after jumping the pins. If the valve is closed and refrigerant continues to flow, then check valve is leaking. Use a pinch off tool and crimp the tubing between the check valve & EEV.

What is EEV valve?

EEVs. The electronic expansion valve (EEV) operates with a much more sophisticated design. EEVs control the flow of refrigerant entering a direct expansion evaporator. They do this in response to signals sent to them by an electronic controller. A small motor is used to open and close the valve port.