Lennox International Inc Lennox Air Handler Connecting Refrigerant Lines, Sealing the Unit

IMPORTANT

If a high­efficiency filter is being installed as part of this system to ensure better indoor air quality, the filter must be properly sized. High­efficiency filters have a higher static pressure drop than standard­efficiency glass/foam filters. If the pressure drop is too great, system capacity and performance may be reduced. The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer, result­ ing in an increase in the number of service calls.

Before using any filter with this system, check the spe­ cifications provided by the filter manufacturer against the data given in the appropriate Lennox Product Specifica­ tions bulletin. Additional information is provided in Ser­ vice and Application Note ACC­00­2 (August 2000).

Supply plenum should be the same size as the flanged opening provided around the blower outlet and should extend at least 3 ft. from the air handler before turning or branching off plenum into duct runs. The plenum forms an extension of the blower housing and minimizes air expansion losses from the blower.

INSTALLING DUCT SYSTEM

Connect supply air duct to the flange on top of the air handler. If an isolation connector is used, it must be nonflammable.

A return air duct system is recommended. If the unit is installed in a confined space or closet, a return connection must be run, full size, to a location outside the closet.

Connecting Refrigerant Lines

Refrigerant lines must be connected by a qualified technician in accordance with established procedures.

IMPORTANT

Refrigerant lines must be clean, dehydrated, refrig­ erant-grade copper lines. Air handler coils should be installed only with specified line sizes for approved sys­ tem combinations.

Handle the refrigerant lines gently during the installation process. Sharp bends or possible kinking in the lines will cause a restriction.

Do not remove the caps from the lines or system connec­ tion points until connections are ready to be completed.

1.Route the suction and liquid lines from the fittings on the indoor coil to the fittings on the outdoor unit. Run the lines in as direct a path as possible avoiding unnecessary turns and bends.

2.Make sure that the suction line is insulated over the entire exposed length and that neither suction nor liquid lines are in direct contact with floors, walls, duct system, floor joists, or other piping.

3.Connect the suction and liquid lines to the evaporator coil.

4.To avoid damaging the rubber grommets in the cabinet while brazing, slide the rubber grommets over the refrigerant lines until they are away from the heat source.

5.Braze using an alloy of silver or copper and phosphorus with a melting point above 1,100°F (593°C).

NOTE — Do not use soft solder.

6.Reinstall the rubber grommets after brazing is finished.

7.Make sure outdoor unit has been put in place according to the Installation Instructions and is connected to the refrigerant lines.

Sealing the Unit

Seal the unit so that warm air is not allowed into the cabinet. Warm air introduces moisture, which results in water blow-off problems. This is especially important when the unit is installed in an unconditioned area.

If installed in an unconditioned space, sealant should be applied around the electrical wires, refrigerant tubing, and condensate lines where they enter the cabinet.

WARNING

There must be an airtight seal between the bottom of the air handler and the return air plenum. Use fiberglass sealing strips, caulking, or equivalent sealing method between the plenum and the air handler cabinet to ensure a tight seal. Return air must not be drawn from a room where this air handler or any gas-fueled appliance (i.e., water heater), or carbon monoxide-producing device (i.e., wood fireplace) is installed.

IMPORTANT

When sealing the cabinet, be sure to seal closed any space around the holes where the drain lines exit the cabinet using duct tape and/or Permagum. Warm air must not be allowed to enter through any gaps or holes in the cabinet.

Make sure the liquid line and suction line entry points are sealed with either ARMAFLEX material or with Permagum. Permagum may also be used to seal around the main and auxiliary drains and around open areas of electrical inlets.

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