Manual 2100-413G
Page
19 of 28
START UP
IMPORTANT INSTALLER NOTE
For improved start up performance wash the indoor coil
with a dish washing detergent.
CRANKCASE HEATERS
SH491-B and -C are provided with compressor
crankcase heat. All other models are not provided with
crankcase heat. They are either single phase or the
system refrigerant charge is not of sufficient quantity to
require crankcase heat.
The SH491-B and -C models have a wrap around type
heater located on the lower section of the compressor
housing. This is an on/off heater that is controlled by
the compressor contactor.
The label in Figure 11 is affixed to all SH491-B and -C
units detailing start up procedure. This is
very
important.
Please read carefully
.
HIGH PRESSURE SWITCH
All models are supplied with a remote reset high
pressure switch. If tripped, this pressure switch may be
reset by turning the thermostat off then back on again.
THREE PHASE SCROLL COMPRESSOR
START UP INFORMATION
Scroll compressors, like several other types of
compressors, will only compress in one rotational
direction. Direction of rotation is not an issue with
single phase compressors since they will always start
and run in the proper direction.
However, three phase compressors will rotate in either
direction depending upon phasing of the power. Since
there is a 50-50 chance of connecting power in such a
way as to cause rotation in the reverse direction,
verification of proper rotation must be made. All three
phase units incorporate a phase monitor to ensure proper
field wiring. See the “Phase Monitor” section later in
this manual.
Verification of
proper rotation
must be made any time a
compressor is changed or rewired. If improper rotation
is corrected at this time there will be no negative impact
on the durability of the compressor.
However, reverse operation for over one hour may have
a negative impact on the bearing due to oil pump out.
NOTE: If compressor is allowed to run in reverse
rotation for several minutes, the compressor’s
internal protector will trip.
FIGURE 11
START UP LABEL
All three phase ZR3 compressors are wired identically
internally. As a result, once the correct phasing is
determined for a specific system or installation,
connecting properly phased power leads to the same
Fusite terminal should maintain proper rotation
direction.
Verification of proper rotation direction is made by
observing that suction pressure drops and discharge
pressure rises when the compressor is energized.
Reverse rotation also results in an elevated sound level
over that with correct rotations, as well as, substantially
reduced current draw compared to tabulate values.
The direction of rotation of the compressor may be
changed by reversing any two line connections to the
unit.
IMPORTANT
THESE PROCEDURES MUST BE
FOLLOWED AT INITIAL START UP
AND AT ANY TIME POWER HAS
BEEN REMOVED FOR 12 HOURS OR
LONGER.
To prevent compressor damage which
may result from the presence of liquid
refrigerant in the compressor crankcase:
1.
Make certain the room thermostat is in
the “off” position. (The compressor is
not to operate.)
2.
Apply power by closing the system
disconnect switch. This energizes the
compressor heater which evaporates
the liquid refrigerant in the crankcase.
3.
Allow 4 hours or 60 minutes per pound
of refrigerant in the system as noted
on the unit rating plate, whichever is
greater.
4.
After proper elapsed time the
thermostat may be set to operate the
compressor.
5.
Except as required for safety while
servicing, do not open system
disconnect switch.
7961-411
