Manual
2100-488
Page
17 of 26
START UP
IMPORTANT INSTALLER NOTE
For improved start-up performance, wash the indoor coil
with a dishwashing detergent.
CRANKCASE HEATERS
WH423D units are provided with compressor crankcase
heat. WH484D and WH604D units are not provided
with crankcase heat. These units utilize scroll
compressors which do not require crankcase heat in this
application.
The WH423D models have an insertion well-type heater
located in the lower section of the compressor housing.
This is a self-regulating type heater that draws only
enough power to maintain the compressor at a safe
temperature on these units.
Some form of crankcase heat is essential to prevent
liquid refrigerant from migrating to the compressor,
causing oil pump out on compressor start-up and
possible valve failure due to compressing a liquid.
The decal in Figure 10 is affixed to all WH423D units
detailing start-up procedure. This is very important.
Please read carefully.
HIGH PRESSURE SWITCH
The 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 scroll units incorporate a phase monitor to ensure
proper field wiring. See the Phase Monitor 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.
FIGURE 10
START UP LABEL
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 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
