16
M
od
Pac II, 9/09-15
6. Apply a bead of silicone where the flashing and side brackets contact the unit and the building
wall.
7. Fasten the flashing to the unit casing and the building wall using #10 x 1/2 inch sheet metal
screws.
8. On the inside of the building, install the wall sleeves in the supply and return air openings. The
sleeves may be trimmed to fit flush with the inside wall. For units with electric heat, a one inch
clearance is required around the duct extensions. The duct extensions must be constructed of
galvanized steel with a minimum thickness of .019” as per the NFPA standards 90A & 90B.
9. Check the fit of each sleeve to its mating flange for possible air leaks. Apply silicone sealer
to close any gaps. Install the air return and supply grilles.
2.9 Electrical Connections
IMPORTANT!
All electrical work must meet the requirements of local codes and ordinances.
Work should
be done
only
by qualified persons.
Scroll compressors are standard on the M
od
Pac II™ models AVP42,48 and 60. They may be
ordered as an option on the models AVP24, 30 and 36. Scroll compressors, like several other types
of compressors, will only compress in one rotational direction. The direction of rotation is not
an issue with single-phase compressors since they will always start and run in the proper direc-
tion. However, three phase compressors will rotate in either direction depending upon phasing of
power. Since there is a 50-50 chance of connecting power in such a way as to cause rotation in the
reverse direction, it is imperative to confirm that the compressor is rotating in the proper direction
at the initial field start-up of the system. Verification of proper rotation is made by observing that
the suction pressure drops and the discharge pressure rises when the compressor is energized. An
alternate method of verification for self contained system with small critical refrigerant charges,
where the installation of gauges may be objectionable, can be made by monitoring the temperature
of the refrigerant lines at the compressor. The temperature should rise on the discharge line while
the suction line temperature decreases. Reverse rotation also results in a substantially reduced
current draw when compared to tabulated values.
There is no negative impact on durability caused by operating three phase compressors in the
reversed direction for a short duration of time, usually defined as less than one hour. However,
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow safety warnings exactly could result in serious injury, death, and/or
property damage.
Turn off electrical power at fuse box or service panel BEFORE making any electrical
connections and ensure a proper ground connection is made before connecting
line voltage.
CAUTION
ModPac II™ A/C units incorporate an internal crankcase heater for compressor
protection. The crankcase heater must be energized for at least 24 hours prior to
starting the compressor.
