Manual 2100-349
Page 12
START UP
IMPORTANT INSTALLER NOTE
For improved start-up performance, wash the indoor
coil with a dishwasher detergent.
CRANKCASE HEATERS
WL701 units are provided with compressor crankcase
heat.
The WL701 model has 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.
Some form of crankcase heat is essential to prevent
liquid refrigerant from migrating to the compressor,
casing oil pump out on compressor start-up and possible
valve failure due to compressing a liquid.
The decal in Figure 9 is affixed to all WL701 unit
detailing start-up procedure. This is very important.
Please read carefully.
HIGH PRESSURE SWITCH
The WA701 and WA721 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 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 ZR3 compressors are wired identical
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
FIGURE 9
START-UP LABEL
