Manual 2100-526E
Page
14 of 24
START UP CONTINUED
IMPORTANT INSTALLER NOTE
For improved start-up performance, wash the indoor coil
with a dishwasher detergent.
CRANKCASE HEATERS
All units covered in this manual are provided with
compressor crankcase heat.
This crankcase heater is a band type heater located
around the bottom of the compressor. This heater is
controlled by the crankcase heater relay. The heater is
only energized when the compressor is not running.
Crankcase heat is essential to prevent liquid refrigerant
from migrating to the compressor, preventing oil pump
out on compressor start-up and possible bearing or scroll
vane failure due to compressing a liquid.
The decal in Figure 7 is affixed to all model units
detailing start-up procedure. This is very important.
Please read carefully
.
HIGH & LOW PRESSURE SWITCH
All models covered by this Manual are supplied with a
remote reset high pressure switch and low 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 change 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.
All three phase ZPS 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 tabulated 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 properly 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.
7961-061
See “Phase Monitor”, Page 16.
FIGURE 7
START-UP LABEL
