Bard 11EER QH Series, Руководство по установке

Страница: 27 / 54

Manual 2100-742A
Page 27 of 54
pressure switch settings: Opens 14 +/– 4 PSI, closes
30 +/– 5 PSI. Refer to defrost control board for lockout
information.
Three Phase Scroll Compresser 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. A phase
rotation meter can be used to verify a clockwise
phase is being supplied. Verification of proper rotation
direction can also be 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
rotation, as well as substantially reduced current draw
compared to tabulated values.
Verification of
proper rotation must be made at the time
the equipment is put into service. 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 1 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 an extended period of time, the
compressor’s internal protector will trip.
All three phase 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.
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 scroll compressors are
equipped with a three 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 (call for cooling) is present at the
phase monitor and phases are correct, the green LED
will light.
NOTE: The phase monitor will not show phase reversal
until the compressor is energized during a call
for cooling or heat pump operation.
If phases are reversed, the red fault LED will be lit and
compressor operation is inhibited. The phase monitor
will also inhibit operation for an imbalance exceeding
12% at 208 VAC and 8% at 460 VAC.
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.
Condenser Fan Operation
NOTE:
Certain models may be equipped with a low
ambient control (LAC), and if so, the condenser
fan motor will have a delayed start until system
refrigerant operating pressure builds up. After
starting, the fan motor may or may not cycle
depending upon ambient conditions. This is
normal operation.
Service Hints
1. Caution owner/operator to maintain clean air filters
at all times and also not to needlessly close off
supply and return air registers. This reduces airflow
through the system, which shortens equipment
service life as well as increasing operating costs.
2. Check all power fuses or circuit breakers to be sure
they are the correct rating.
3. Periodic cleaning of the outdoor coil to permit full
and unrestricted airflow circulation is essential
.
Sequence of Operation
Cooling
With Y1-Y2 jumpers installed, circuit R-Y1 makes at
thermostat pulling in compressor contactor, starting
the compressor, indoor blower (rated air) and outdoor
motor. (See
NOTE under CONDENSER FAN
OPERATION concerning models equipped with
low ambient control.) The G (indoor motor) circuit is
automatically completed by the thermostat on any call
for cooling operation or can be energized by manual fan
switch on subbase for constant air circulation.
Heating
A 24V solenoid coil on reversing valve controls heating
cycle operation. Two thermostat options, one allowing
“Auto” changeover from cycle to cycle and the other
constantly energizing solenoid coil during heating
season—thus eliminating pressure equalization noise
except during defrost, are to be used.
On “Auto” option, a circuit is completed from R-B/W1
and R-Y1 on each heating “on” cycle, energizing reversing
valve solenoid and pulling in compressor contactor,
starting compressor and outdoor motor. R-G also make
starting indoor blower motor. Heat pump heating cycle
now in operation.
The second option has no “Auto” changeover position, but
instead energizes the reversing valve solenoid constantly
whenever the system switch on subbase is placed in