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Refrigeration Coil FAQs

Q. What is a refrigeration coil?

A. The equipment that air flows through which either extracts the heat out of the air or puts heat into the air.


Q: What types of refrigeration coils are available?

A: Coils are designed for air to flow through them in an upward, downward, or sideways application. The up-flow coil would sit on top of the furnace, the down-flow coil under the furnace, and the horizontal flow coil beside the furnace. All refrigeration coils have a drain built into the coil base which water must drain out of during the cooling season. Coils are also made according to the freon pressures that will flow through them, the R410-A freon has a much higher pressure than R22.

Q: Why is proper refrigeration coil sizing important?

A: The coil being matched to the outdoor equipment is what determines how efficient the systems potential efficiency is. The coil also has a large impact on the air flow through the ducting. Both of these items must be considered when selecting a coil.


Q: Can I use an existing refrigeration coil when replacing the outdoor equipment?

A: It's possible, but not likely. With the industry switching to the R410-A freon, the pressures would rupture a coil that was designed for R22 freon. Also, old coils were designed to work with the less efficient outdoor units that were made years ago, so it would be like putting a governor on an engine. An old coil will not let the new outdoor equipment reach the potential efficiency or capacity it is designed to achieve.


Q: What is a TXV? Is it necessary?

A: This is a Thermal Expansion Valve. This is a metering device that adjusts freon flow rates through the coil. There is a simpler metering devise, but the TXV is more accurate and is often required to achieve the highest efficiency ratings.


 Q: There appears to be a second drain on my refrigeration coil, but it's not being used. Is this important?

A: Yes, it's important. Most refrigeration coils have 2 drain outlets. If the primary drain gets plugged, the condensate still needs to have a path out of the coil other than to spill into the ducting (This will rust out your ducting and possible mould or mildew issues. Worse yet is the risk of structural damage (i.e. ceiling being damaged if the coil is in the attic without an auxillary drain and drain pan). Code requires either the secondary drain be taken to "a conspicuous location" or an overflow switch be installed.

Q: My refrigeration coil is setting directly on the wood equipment platform in my garage. I have noticed a water stain around this. Does this mean its leaking?
A: Possibly. It's important to verify that the water damage is not coming from something else. Other causes for water stains on the platform are a leaking water pipe, roof damage, condensate from a 90% furnace, the refrigeration lines not being insulated, or a leaking pressure relief valve on the water heater.