What Is a TXV and What Does It Do in My HVAC System?

Quick Answer

A TXV, or thermostatic expansion valve, controls how much refrigerant flows into your evaporator coil. It adjusts the flow to match how much cooling your home needs, which keeps the system efficient across changing conditions.

What Is a TXV?

Quick Answer:

A TXV is a metering device that sits at the entrance to the evaporator coil. It senses temperature and pressure and opens or closes to let in just the right amount of refrigerant for current conditions.

It replaces older fixed-orifice metering, which could not adjust. By matching refrigerant flow to demand, a TXV helps your system run efficiently whether it is mildly warm or sweltering outside.

What Does a TXV Do?

Quick Answer:

It keeps the evaporator coil fed with the correct refrigerant flow so the system absorbs heat efficiently. Too little flow and the coil cannot cool well; too much and liquid can reach the compressor and damage it.

By holding the right balance automatically, the TXV protects the compressor and keeps cooling steady. It is a small part with a big effect on efficiency and equipment life.

What Are the Signs of a Failing TXV?

Quick Answer:

Weak or uneven cooling, frost or ice on the coil or refrigerant line, and a system that short-cycles can all point to a TXV that is stuck or failing. These overlap with other issues, so a technician should confirm it.

A stuck TXV starves or floods the coil, which hurts comfort and can harm the compressor. A technician can test it and replace it if needed, restoring proper refrigerant flow.

At a Glance

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Frequently Asked Questions

Where is the TXV located?

The TXV sits at the inlet of the indoor evaporator coil, where refrigerant enters to absorb heat. Because it is tucked into the coil assembly, diagnosing or replacing it is a job for a technician.

Can a TXV be replaced?

Yes. A failing TXV can be replaced by a qualified technician, who recovers the refrigerant, swaps the valve, and recharges the system. It restores proper refrigerant flow and efficient cooling when the old one sticks.

What is the difference between a TXV and an orifice?

An orifice is a fixed opening that cannot adjust, while a TXV varies refrigerant flow to match demand. The TXV is more efficient across changing conditions, which is why modern systems use it.

Have a Question About Your System?

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