Manual 2100-408C
Page
16
START UP
IMPORTANT INSTALLER NOTE
For improved start-up performance, wash the indoor coil
with a dishwashing detergent.
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 insure 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.
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.
PHASE MONITOR
All units with three phase compressors are equipped
with a 3 phase line monitor to prevent compressor
damage due to phase reversal.
The phase monitor in this unit is equipped with two
LEDs. If the Y signal is present at the phase monitor
and phases are correct, the green LED will light. If
phases are reversed, the red fault LED will be lit and
compressor operation is inhibited.
If a fault condition occurs, reverse two of the supply
leads to the unit. Do not reverse any of the unit factory
wires as damage may occur.
SERVICE HINTS
1. Caution homeowner to maintain clean air filters at all
times. Also, not to needlessly close off supply and
return air registers. This reduces air flow through the
system, which shortens equipment service life as well
as increasing operating costs.
2. Switching to heating cycle at 75° F or higher outside
temperature may cause a nuisance trip of the remote
reset high pressure switch. Turn thermostat off, then
on to reset the high pressure switch.
3. The heat pump wall thermostats perform multiple
functions. Be sure that all function switches are
correctly set for the desired operating mode before
trying to diagnose any reported service problems.
4. Check all power fuses or circuit breakers to be sure
they are the correct rating.
5. Periodic cleaning of the outdoor coil to permit full
and unrestricted airflow circulation is essential.
SEQUENCE OF OPERATION
OCCUPIED MODE
VENTILATION SEQUENCE
– The ERV and indoor
blower will be continuously energized when the A1
terminal is energized.
COOLING SEQUENCE
– On a call for cooling, the
compressor of the unit is energized to provide cooling.
A call for cooling cancels dehumidification mode.
Cooling mode is only available when the timer is
energized.
Circuit R-Y makes at thermostat pulling in compressor
contactor, starting the compressor and outdoor motor.
The G (indoor motor) circuit is automatically completed
on any call for cooling operation or can be energized by
manual fan switch on subbase for constant air
circulation. Refer to Figure 13.
