Specifications
8
Table 6-CAPACITY CONTROL
TRANS SW* POS1 TRANS SW* POS2
Oper Cyl Oper Cyl
Ck t Ck t
UNIT
30HR
30HS
CONTR
STEPS
%
Cap
Total
1 2
%
Cap
Total
1 2
1 40 4 4 - 20 2 - 2
2 60 6 4 2 60 6 4 2
3 80 8 6 2 80 8 4 4
040
050
4 100 10 6 4 100 10 6 4
1 33 4 4 - 33 4 - 4
2 66 8 4 4 66 8 4 4
3 83 10 6 4 83 10 4 6
060
4 100 12 6 6 100 12 6 6
1 - -
- - -
-
2 - -
- -
3 - -
- -
LLSV
(
=
Open)
4 - -
- -
LLSV – Liquid Line Solenoid Valve
* Transfer Switch, manually operated.
Compressor starting sequence: Pos 1, 1-2: Pos 2, 2-1.
DESIGN SET POINT ADJUSTMENT
Adjust set point by Rotating switch in the panel.
О
SET POINT ADJ.
C
0
SET POINT
L.W& SET POINT DISPLY
О
L.W.T
4
3 2 1
О
О О О
SET INDICATORS
220
SENSOR
ON
ON
ON
ON
ON
ON
ON
ON
Table 7– CIRCUIT DATA
UNIT 30HR,HS 040 050 060
CIRCUIT NO.
1 2 1 2 1 2
Compressor No*
1 2 1 2 1 2
Comp. Size (nom tons)
20 20 30 20 30 30
No. Comp. Cylinders
4 4 6 4 6 6
No. Comp. Unlooders†
1 1 1 1 1 1
* Numbered left to right, viewed from front of unit.
† Electric solenoid type.
OPERATION
Sequence of Control-Power is supplied to Control circuit
either from a separate source or thru a field-installed
transformer (accessory package) with primary connected to
unit power terminal block (installation instructions furnished
with accessory transformer package). Control circuit is
energized thru a circuit breaker on control panel. This server
as ON-OFF switch for control circuit.
Crankcase heaters are wired they are operative as long as
control circuit breaker is on, regardless of condition of other
safety devices. When a compressor stops, its heater is turned
on to prevent refrigerant absorption by oil in the crankcase.
Control circuit breaker should be off only when unit is
being serviced. After a prolonged shutdown, energize
crankcase heaters for 24 hours before starting compressors.
With power to control circuit terminals 15 and 16 and
control circuit breaker in "on" position, unit is ready for
operation providing all safety devices are satisfied, interlocks
are closed and instructions on warning labels have been
followed.
When the START-STOP switch is turned to "Start", the
panel light will come on and timer motor will start. If
temperature controller is calling for cooling, No. 1 compressor
will start immediately. After 15 seconds, if required by load
demand, no. 2 compressor will start. At this point, timer motor
will stop with timer switch contacts A-A1 and B-B1 made;
temperature controller then takes over. This timer position
will hold during unit operation, while temperature controller
cycles compressors off and on and alternately loads and
unloads cylinders in each compressor to control cooling
capacity in response to load requirements.
Operator should use sequence transfer switch on control
panel to change lead compressor periodically: this equalizes
compressor wear. A panel light for each circuit shows which
compressor is running. Stop unit before changing starting
sequence.
Unit Stoppage (other than supply power interruption)- Water-
cooled (30HR) units and condenser less (30HS) units
completely stop if the START-STOP switch is turned to
"Stop", low water temperature cutout contacts open, contacts
of any auxiliary interlock in the chilled water system open, or
control circuit breaker trips.
Individual Compressor Stoppage-Motor winding thermal
protector contacts open, high- or low-pressure switch
in the refrigerant circuit opens, oil pressure safety switch
opens, or contacts of any auxiliary interlocks in refrigerant
circuit open. Safety devices in one circuit do not affect
operation of other circuit. A tripped main-power circuit
breaker will stop the compressor in that circuit.
Besides stopping compressor, the following devices close
liquid line solenoid valve in each refrigerant circuit; internal
motor thermal protectors, oil safety switch, high– pressure
switch. Cutout of low-pressure switch will not close liquid
line valve.
Restart After Stoppage By Safety Device
LOW WATER TEMPERATURE CUTOUT–Manually
depress reset button on control panel.
STEPS OUTPUT
Fig .4 set point Adjustment