292424-XIM-A-0307
Unitary Products Group
9
COMPRESSOR CRANKCASE HEATER
The compressor is equipped with a crankcase heater to pre-
vent refrigerant from mixing with crankcase oil during the
OFF cycle. The heater will be energized when the compres-
sor is not running providing the unit disconnect switch is
closed.
If a unit has just been installed or the unit disconnect switch
has been open for a long period of time, move the system
switch on the room thermostat to the OFF position before
closing the unit disconnect switch. Up to eight hours of crank-
case heat can be required to drive the liquid refrigerant out of
the compressor before the compressor can be started.
REFRIGERANT PIPING
GENERAL GUIDELINES
Many service problems can be avoided by taking adequate
precautions to provide an internally clean and dry system and
by using procedures and materials that conform with estab-
lished standards.
Use hard drawn copper tubing where no appreciable amount
of bending around pipes or other obstructions is necessary.
Use long radius ells wherever possible with one exception
short radius ells for the traps in all suction risers. If soft cop-
per is used, care should be taken to avoid sharp bends which
may cause a restriction.
Pack fiber glass insulation and a sealing material such as
permagum around refrigerant lines where they penetrate a
wall to reduce vibrations and to retain some flexibility.
Support all refrigerant lines at minimum intervals with suitable
hangers, brackets or clamps.
Braze all copper to copper joints with Silfos-5 or equivalent
brazing material. Do not use soft solder.
Insulate all suction lines with a minimum of 1/2" (12.7mm)
ARMAFLEX or equal. Liquid lines exposed to direct sunlight
and/or high temperatures must also be insulated.
Never solder suction and liquid lines together. They can be
taped together for convenience and support purposes, but
they must be completely insulated from each other.
A filter-drier MUST be installed in the liquid line of every sys-
tem to prevent dirt and moisture from damaging the system.
A properly-sized filter-drier is shipped with each condensing
unit for field installation near the evaporator coil.
The filter-drier is shipped inside the unit control box.
NOTE:
Installing a filter-drier does not eliminate the need
for the proper evacuation of a system before it is
charged.
Install a moisture indicating sight glass in the liquid line
between the filter-drier and the evaporator coil.
FIGURE 4 - UNIT 4 POINT LOAD
TABLE 7: UNIT 4 POINT LOAD WEIGHTS
UNIT
4 - Point Load (lbs./Kg)
Total
A
B
C
D
150
930/421
325/147
218/99
155/70
232/105
180
990/449
346/157
232/105
165/75
247/112
240
1012/459
353/160
235/106
168/76
254/115
Do not attempt to start the compressor without at
least eight hours of crankcase heat or compressor
damage can occur.
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