Will Installing A TXV kit on Air Handler Solve Seer Rating Problem

by Courtney
(Henderson Nevada USA)

Will installation of a TEV or TXV kit on my air handler/ceiling fan coil solve the problem of my air handler with a SEER of 9 and my condenser unit with a SEER of 13/2.5 ton not being a matched system?

My neighbors have bought new condenser units but not bought new air handlers and the SEER ratings of these do not match up. Certain HVAC companies in town here are telling me that this will cause efficiency, capacity and life of the condenser unit problems down the line.

I hate to have to buy a whole new system for my 17 year old condo when I do not plan to be here more than a couple more years and the value has come down appreciably.

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starstarstarstarstar 		Matched Systems provide greatest PEDaL NEW
by: Brian M. Service Manager

The cornerstones of a properly designed and installed temperature control system in my opinion after 30+ years in this industry would be Performance, Efficiency, Dependability and Longevity (PEDaL) of the equipment. To achieve optimal PEDaL it is necessary to be able to pick up and dump the heat from the house effectively. An evaporator coil has "X" amount of surface area and tubing to allow vaporized refrigerant inside the coil to contact the indoor air outside the coil to "remove" (transfer) heat from it. The condensing unit similarly has a fixed amount of coil with which to "dump" the collected heat from inside the home to the outside air. This is done through the process of removing the heat from the refrigerant until it condenses to a liquid then pushing the liquid inside to the evaporator coil and through either a "fixed" (flo-rator) or variable (TXV) orifice to vaporize the refrigerant and cause it to absorb ("Collect") heat. Which is then carried out through the compressor (pump) and then pushed through the condenser coil (to remove the heat again) this process runs continuously until the house is at temperature or something fails. A higher efficiency condensing unit can be made to "cool" on a less efficient evaporator coil with either a flo-rator or a txv metering device. This however requires that the system overall be charged with more refrigerant to compensate for the ability to more efficiently "dump" heat than we can "collect" it. Over charging the system holds the pressures "up" and prevents the system form "freezing" or "icing up" the evaporator coil. This is possible because refrigerants are pressure/temperature tied. The detractors to this practice are that the system will operate at lower than rated energy efficiency (or seer), the increased pressure place more than designed stress on the compressor and other components in the system leading to shorter than designed service life spans. The risk of not vaporizing all of the refrigerant before it reaches the compressor is increased - as basic physics tells us that liquids do not compress this increases the risk of catastrophic mechanical failure of the compressor. A TXV improves the situation by providing for variable adjustment of the refrigerant metering lowering the negative effects compared to a flo-rator but, is not the "fix-all". In the end is the short term savings on investment provided by this "Band-Aid" application is not worth the long term negative effects it creates. On the upside it does provide you with information - no contractor that values their reputation would offer to perform such an installation. So this can help you separate the professional HVAC-R contractors from the pretenders who can only offer "low price" by providing low quality work. You will receive better PEDaL and long term satisfaction both while you live in the condo and when you sell it by utilizing a professional contractor that will not take short-cuts and provide you with a cut-rate repair. While a lot of "companies" offer to install "boxes". There is a science to doing HVAC-R service and installation properly. As well you should have them make sure that your air ducting is sized, sealed and insulated properly while they are there. All of these will greatly affect the overall PEDaL of your system.
Rating
starstarstarstarstar 		Matched Systems provide greatest PEDaL NEW
by: Brian M. Service Manager

The cornerstones of a properly designed and installed temperature control system in my opinion after 30+ years in this industry would be Performance, Efficiency, Dependability and Longevity (PEDaL) of the equipment. To achieve optimal PEDaL it is necessary to be able to pick up and dump the heat from the house effectively. An evaporator coil has "X" amount of surface area and tubing to allow vaporized refrigerant inside the coil to contact the indoor air outside the coil to "remove" (transfer) heat from it. The condensing unit similarly has a fixed amount of coil with which to "dump" the collected heat from inside the home to the outside air. This is done through the process of removing the heat from the refrigerant until it condenses to a liquid then pushing the liquid inside to the evaporator coil and through either a "fixed" (flo-rator) or variable (TXV) orifice to vaporize the refrigerant and cause it to absorb ("Collect") heat. Which is then carried out through the compressor (pump) and then pushed through the condenser coil (to remove the heat again) this process runs continuously until the house is at temperature or something fails. A higher efficiency condensing unit can be made to "cool" on a less efficient evaporator coil with either a flo-rator or a txv metering device. This however requires that the system overall be charged with more refrigerant to compensate for the ability to more efficiently "dump" heat than we can "collect" it. Over charging the system holds the pressures "up" and prevents the system form "freezing" or "icing up" the evaporator coil. This is possible because refrigerants are pressure/temperature tied. The detractors to this practice are that the system will operate at lower than rated energy efficiency (or seer), the increased pressure place more than designed stress on the compressor and other components in the system leading to shorter than designed service life spans. The risk of not vaporizing all of the refrigerant before it reaches the compressor is increased - as basic physics tells us that liquids do not compress this increases the risk of catastrophic mechanical failure of the compressor. A TXV improves the situation by providing for variable adjustment of the refrigerant metering lowering the negative effects compared to a flo-rator but, is not the "fix-all". In the end is the short term savings on investment provided by this "Band-Aid" application is not worth the long term negative effects it creates. On the upside it does provide you with information - no contractor that values their reputation would offer to perform such an installation. So this can help you separate the professional HVAC-R contractors from the pretenders who can only offer "low price" by providing low quality work. You will receive better PEDaL and long term satisfaction both while you live in the condo and when you sell it by utilizing a professional contractor that will not take short-cuts and provide you with a cut-rate repair. While a lot of "companies" offer to install "boxes". There is a science to doing HVAC-R service and installation properly. As well you should have them make sure that your air ducting is sized, sealed and insulated properly while they are there. All of these will greatly affect the overall PEDaL of your system.
Rating
starstarstarstarstar 		Seer rating
by: Chester

To get the true SEER rating out a system you must match the coil in the air handler to the condensing unit. It is best to use a TXV metering device in any system, but adding a TXV will not make your evaporator match your condenser. The new air handler with the proper coil will not be all that expensive and will pay for it's self in about 3 years with improved cost of operation.

Put in a new matched system, with a TXV and you should cut your cooling bill by about 25%
Rating
starstarstarstarstar 		Installing TXV
by: Dadan

I really can’t tell you how the manufacture rates the TXV or it seer rating. All I know is seer rating is overall operating of the entire central ac unit. (It’s not accurate unit of measurement, but they decide to go with it.)

Yes, TXV is the best kind of expansion valve out there, but I doubt adding a TXV will increase the seer rating by 4! Manufacture have sheet of page tell you what unit seer rating goes with what.

Yes, opening the central ac unit will cause problem down the line, you open the central ac unit when there is no other option. Don’t do if you need to modify some part, it will cause you problem and money.

I hope I had answer your question.

Dadan

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