Miscellaneous

How do I know if my metering device is bad?

How do I know if my metering device is bad?

Symptoms

  1. Frost on the valve or indoor coil.
  2. Low pressure reading at the suction service valve.
  3. High superheat.
  4. High liquid pressure at the the liquid line valve.

How much does a expansion valve replacement cost?

A TXV expansion valve manages the amount of liquid refrigerant flowing through the air conditioning system, so if it goes bad, you’ll need to replace it to keep your AC functioning properly. Expect to pay an average of $400 to get the job done, but it may cost as little as $200 or as much as $700.

What are the symptoms of a bad TXV?

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.

How long does it take to change a TXV valve?

If the valve is all mechanical, it will take about 15 minutes. I have never had to pull the coil after changing at least a hundred expansion valves.

What is a piston metering device?

Fixed metering device- If an air conditioning system contains a fixed metering device, such as a piston, the correct method of evaluating refrigerant charge is superheat. The fixed orifice metering device, containing a piston, produces a steady flow of refrigerant into the evaporator coil.

Where is a metering device located?

condenser coil
The metering device is located after the condenser coil. There are two kinds of metering devices, thermal expansion valves (TXV) and capillary tubes. Either one does the same thing; they lower the high-pressure liquid pressure by forcing it through a small hole or nozzle.

What happens at the metering device?

The metering device is responsible for feeding the proper amount of refrigerant to the evaporator coil. The refrigerant that enters the metering devices is a high temperature, high pressure, subcooled liquid that leaves the devices as a low-temperature, low-pressure saturated liquid.