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Thursday, December 4, 2014

All about the TXV Valve.

The TXV Valve (also known as the Thermal Expansion Valve) is a vital component to higher efficiency air conditioning systems. The TXV valve is typically associated with higher efficiency air conditioning systems because of it's ability to regulate the amount of freon that enters the coil. It changes the amount of freon flow based on the conditions of the cooling needs and environmental variables. It's cousin the Accurator is not as efficient as the TXV because it relies on system pressure dynamics to regulate freon flow. 
txv-valce-aircool
Standard TXV Valve

There are always pros and cons to every situation. In this case, the pros seem to outweigh the cons when it comes to energy saving over time. One of the downsides of the TXV could be that it has moving parts, and is a mechanical device. With any component that has moving parts, the possibility for mechanical failure exists. So, many people in the know recommend the standard Accurator system for it's reliability. One must then weigh the risk of mechanical failure repair cost with the savings of having a more efficient system overall. Also consider that both the TXV and the Accurator have small orifices or holes for the freon to pass through which could get clogged or restricted.

The main benefit of the TXV is how it adjusts the freon flow according to the cooling load needed. If perhaps it is very hot outside today, the TXV will open wider to let more freon flow through the evaporator coil. This will increase the cooling capacity of the unit, keeping it in the target efficiency range for the unit. If tomorrow is cooler outside, the TXV will close off more. This will restrict the flow of freon to match the efficiency needed.
txv-sensing-bulb
Sensing Bulb

This function does more than save you money on power bills, but it also has life preserving effects on other parts of the air conditioning system. For instance, the compressor which pumps the freon through the system is made to specifically pump freon in the gaseous state. Freon, depending on it's temperature and pressure changes from a liquid to a gas in the ac system. It changes back and forth from liquid to gas and back over and over as it cycles through the system. That is actually normal for it's operation. As the freon passes by the evaporator, it is supposed to take in enough heat to turn completely into a gas before returning to the compressor. If the TXV is not regulating correctly or there is no TXV present in the system, there is the possibly of improper or insufficient heat exchange happening in the evaporator coil. This could cause the freon to remain in the liquid state and eventually return to the compressor as a liquid. This will certainly damage the valves inside the compressor. It may take days, months or years for this to occur, but I can assure you that damage is being done to the compressor valves. So, having a properly operating metering device in the ac unit, can protect other components from damage.

Having a TXV installed in your system can also help the technician diagnose problems with the system with greater accuracy. Having a TXV regulating superheat in the system can allow the technicians more accuracy when reading pressures while diagnosing problems. It can be vital to charging the air conditioning system with the correct amount of freon. I have heard that around 70% of all residential ac systems may not be charged correctly. Now there could be many many reasons for this, but having a TXV enables a technician to rule out the metering device as the culprit of an issue such as this.
another-view-TXV
Another View - TXV Valve

If you are in the market for a high efficiency ac system, you probably will get a unit which already comes with a TXV as part of the system. However, keep in mind that a TXV can be installed in most systems even if they were not originally manufactured with one. The decision must be made by the owner if retrofitting a TXV into their system is worth the cost of the installation.

Most systems sold today will have a TXV already installed, due to changes in efficiency regulation which occurred in January 2006. The minimum requirement is 13 SEER, which would need a TXV to maintain that efficiency in most cooling conditions. While there are many aspects of the air conditioning system which contribute to its operating efficiency, the TXV is one of the significant ones to mention. I hope this helps you understand more about the air conditioning system in general. We want you to be informed in order to make better decisions. Feel free to contact us on our website's Contact Page. Stay tuned for more posts about the world of Air Conditioning.
13 SEER in January 2006
13 SEER in January 2006
13 SEER in January 2006
13 SEER in January 2006
13 SEER in January 2006