How to Install an HVAC Coil

Preparation

• 1

  Place the evaporator coil and evaporator box on a flat, open work surface, such as a garage floor. The evaporator box comes with the coil and provides housing for the unit.

• 2

  Measure the height and depth of the box. Measure the area where you removed the old coil. Compare the measurements to ensure that the new coil box fits in the required space.

• 3

  Connect the orifice distributor to the orifice distributor hub. The distributor consists of a coupling connected to a series of wire-like pipes. Screw it into the bottom of the distributor hub, a spout-like piece above the distributor. Follow the installation manual instructions for the placement of any seals between the two -- a leak at this connection can cause serious problems.

• 4

  Locate the front of the evaporator box. The front contains a series of holes in a solid metal plate.

• 5

  Place the evaporator coil in the box so the pipes that protrude from the front of the coil and the drainage holes at the bottom of the coil line up with the holes in the front of the evaporator box.

• 6

  Carry the coil to the installation site. Ask a friend or family member for assistance if necessary.

Installation

• 7

  Turn off power to the HVAC unit at the household breaker panel. Turn the HVAC system off as well.

• 8

  Slide the coil box into the area previously occupied by the old evaporator coil.

• 9

  Locate all of the pipes to connect to the evaporator coil. You should find one pipe, usually copper, to attach to the steam header, or the pipe outlet above the orifice distributor hub on the coil; there should be another pipe, again typically copper, to attach to the distributor hub. Finally, there should be at least one drainpipe made of polyvinyl chloride (PVC) or another plastic.

• 10

  Place joint compound around the end of the steam header piping and the steam pipe that leads to the evaporator. The steam pipe consists of the topmost copper pipe.

• 11

  Attach the steam header to the existing steam pipe by placing a coupling over the end of the header and piping then screwing down to tighten it. Use a coupling recommended by the coil manufacturer. If the steam header does not reach all the way to the piping, extend a new length of pipe from the header to the pipe in the same manner that you installed the coupling.

• 12

  Put on work gloves and safety glasses. Apply solder around the edges of the coupling then heat it with the torch until the solder melts and welds the pipes together.

• 13

  Repeat the connection process to attach the orifice extension hub to the other copper piping system that leads to the evaporator coil.

• 14

  Locate the drain outlet at the bottom of the coil. The drain outlet consists of two small holes with threaded interiors.

• 15

  Attach the drainpipe to the drain outlet on the evaporator coil. Screw the threaded end of the existing drain line into the drain outlet. If there is no threaded end, install a new length of pipe with threaded ends to fit between the drainpipe and drain outlet.

• 16

  Plug any unused drain outlets on the coil with drain plugs. Evaporator coils usually have multiple evaporator coils in case the installation site has multiple drain lines. Connect as many drain lines, as necessary, to the outlets and plug any additional outlets with plugs provided by the coil manufacturer. Screw the plugs into the outlets with a flathead screwdriver.