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7. REFRIGERANT CONNECTIONS
Keep the coil connections sealed until refrigerant connections are
made. See the Installation Instructions for the outdoor unit for details
on line sizing, tubing installation, and charging information.
Coil is shipped with “N2”. Evacuate the system before charging with
refrigerant.
Install refrigerant tubing so that it does not block service access to
the front of the unit.
Nitrogen should flow through the refrigerant lines while brazing.
Use a wet rag or an approved heat paste to protect the TXV sensing
bulb during the braze process.
After the refrigerant connections are made, seal the gap around the
connections with pressure sensitive gasket.
Do not, under any circumstances, connect return ductwork to any
other heat producing device such as fireplace insert, stove, etc.
Unauthorized use of such devices may result in fire, carbon
monoxide poisoning, explosion, personal injury or property
damage.
Sheet metal ductwork run in unconditioned spaces must be insulated
and covered with a vapor barrier. Fibrous ductwork may be used if
constructed and installed in accordance with SMACNA Construction
Standard on Fibrous Glass Ducts. Ductwork must comply with
National Fire Protection Association as tested by U/L Standard 181
for Class I Air Ducts. Check local codes for requirements on ductwork
and insulation.
Duct system must be designed within the range of external static
pressure the unit is designed to operate against. It is important
that the system airflow be adequate. Make sure supply and return
ductwork, grills, special filters, accessories, etc. are accounted for
in total resistance. See airflow performance tables in this manual.
Design the duct system in accordance with “ACCA” Manual “D”
Design for Residential Winter and Summer Air Conditioning and
Equipment Selection. Latest editions are available from: “ACCA”
Air Conditioning Contractors of America, 1513 16th Street, N.W.,
Washington, D.C. 20036. If duct system incorporates flexible air
duct, be sure pressure drop Information (straight length plus all
turns) shown in “ACCA” Manual “D” is accounted for in system.
Supply plenum is attached to the 3/4” duct flanges supplied with
the unit. Attach flanges around the blower outlet.
IMPORTANT: If an elbow is included in the plenum close to the
unit, it must not be smaller than the dimensions of the supply duct
flange on the unit.
IMPORTANT: The front flange on the return duct if connected to
the blower casing must not be screwed into the area where the
power wiring is located. Drills or sharp screw points can damage
insulation on wires located inside unit.
Secure the supply and return ductwork to the unit flanges, using
proper fasteners for the type of duct used and tape the duct-to-
unit joint as required to prevent air leaks.
WARNING
The air distribution system has the greatest effect on airflow. The duct
system is totally controlled by the contractor. For this reason, the
contractor should use only industry-recognized procedures.
Heat pump systems require a specified airflow. Each ton of cooling
requires between 350 and 450 cubic feet of air per minute (CFM), or
400 CFM nominally.
Duct design and construction should be carefully done. System
performance can be lowered dramatically through bad planning or
workmanship.
Air supply diffusers must be selected and located carefully. They must
be sized and positoined to deliver treated air along the perimerter of
the space. If they are too small for their intended airflow, they
become noisy. If they are not located properly, they cause drafts.
Retur
n
air grilles must be properly sized to carry air back to the
blower.
If they are too small, they also cause noise.
The installers should balance the air distribution system to ensure
proper quiet airflow to all rooms in the home. This ensures a comfort-
able living space.
An air velocity meter or airflow hood can be used to balance and verify
branch and system airflow (CFM).
6. DUCTWORK
Field ductwork must comply with the National Fire Protection
Association NFPA 90A, NFPA 90B and any applicable local
ordinance.
Summary of Contents for WATPM Series
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