13500 Industrial Park Blvd., P.O. Box 1551, Minneapolis, Mn. 55440
@
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INTRODUCTION
McQUAY
automatic water cooling units that include the latest in
engineered components arranged to provide a compact and
efficient unit. Each unit is assembled before evacuation,
charging and testing. Each unit consists of an air cooled
condenser with integral subcooler section, unloading
compressor and replaceable tube, shell-and-tube evaporator.
ALR SEASONPAK air cooled water chillers are
NOMENCLATURE
A L R-030 A-S
Air Cooled Condensing
Reciprocating Compressor
INSPECTION
When the equipment is received, all items should be
carefully checked against the bill of lading to insure a
complete shipment. All units should be carefully inspected
for damage upon arrival. All shipping damage should be
INSTALLATION
NOTE: Installation and maintenance are to be performed only by qualified personnel who are familiar
with local codes and regulations, and experienced with this type of equipment. CAUTION: Sharp edges
and coil surfaces are a potential injury hazard. Avoid contact with them.
HANDLING
Care should be taken to avoid rough handling or shock due
to dropping the unit. Do not push or pull the unit from
anything other than the base, and block the pushing vehicle
away from the unit to prevent damage to the sheet metal
cabinet (See Figure 1). Do not let the lifting fork damage
the refrigerant piping within the cabinet.
To lift the unit, 2
provided in the base of the unit. Spreader bars and cables
should be arranged to prevent damage to the condenser
coils or unit cabinet (See Figure 2).
-1/2-inch
diameter lifting holes are
Liquid line components included are manual liquid line
shutoff valve, replaceable core filter-drier, liquid line
solenoid valve, sightglass/moisture indicator and double
diaphragm hydraulic element thermal expansion valve.
Other features include: compressor crankcase heater, an
evaporator heater for chilled water freeze protection and
recycling pumpdown during “on” or “off” seasons.
Nominal Capacity (Tons)
reported to the carrier and a claim should be filed. The unit
serial plate should be checked before unloading the unit to
be sure that it agrees with the power supply available.
FIGURE 1. SUGGESTED PUSHING ARRANGEMENT
r
BLOCKING
LOCATION
Due to vertical condenser design, it is recommended that
the unit be oriented so that prevailing winds blow parallel
to the unit length, thus minimizing effects on condensing
pressure.
manner, a wind deflector should be constructed.
mounted on a roof or concrete slab (ground level
installation). Roof-mounted units should be installed level
on steel channels or an l-beam frame to support the unit
above the roof. Use of vibration pads or isolators is
recommended. The roof must be strong enough to support
the weight of the unit. See Table 1 for unit weights.
Concrete slabs used for unit mounting should be installed
level and be properly supported to prevent settling. A
one-piece concrete slab with footings extended below the
frost line is recommended.
TABLE 1.
If it is not practical to orient the unit in this
Units are designed for outdoor application and may be
UNIT WEIGHTS
ALR MODEL
012
015
020
025
030
OPERATING WEIGHT
1364
1661
1883
2012
2330
(LBS.)
GOOD PUSHING ARRANGEMENT -CABINET DAMAGE UNLIKELY
FIGURE 2.
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WATER PIPING
PIPING PRACTICES
5.
Due to the variety of piping practices; it is advisable to
follow the recommendations of local authorities. They can
supply the installer with the proper building and safety
codes required for a safe and proper installation.
Basically, the piping should be designed with a
minimum number of bends and changes in elevation to
keep system cost down and performance up. It should
contain:
Vibration eliminators to reduce vibration and noise
transmission to the building.
Shut-off valves to isolate the unit from the piping
system during unit servicing. prevent moisture condensation and possible damage to the
Manual or automatic air vent valves at the high points
of the system.
Some means of maintaining adequate system water
pressure (e.g., expansion tank or regulating valve).
COOLER WATER CONNECTIONS
Temperature and pressure indicators located at the unit
to aid in unit servicing.
6.
A strainer or some means of removing foreign matter
from the water before it enters the pump. It should be
placed far enough upstream to prevent cavitation at the
pump inlet (consult pump manufacturer for
recommendations). The use of a strainer will prolong
pump life and thus keep system performance up.
Prior to insulating the piping and filling the system, a
preliminary leak check should be made.
Piping. insulation should include a vapor barrier to
building structure. It is important to have the vapor barrier
on the outside of the insulation to prevent condensation
within the insulation on the cold surface of the pipe.
It is suggested that horizontal water piping connections to
the cooler be made through the holes provided in the base
frame. Two suggested arrangements that will align the
7. Vertical connections may be made to the cooler through
the open base using
2-inch
IPS
90-degree
elbows. Figure 10
gives the necessary dimensions for either piping method.
piping with the base frame holes are shown in Figures 6 and
FIGURE 6.
FIELD
P-
2” IPS WATER PIPE
NOTE: FOR INSTALLING A CHILLED WATER THERMOSTAT IN
RETURN WATER LINE A REDUCING TEE
SE USED INSTEAD OF A 2” IPS 90 ELBOW. SEE FIGURE 8.
-
COOLER WATER CONNECTIONS
INSTA
2”
IPS STREET ELBOW
BASE FRAME
”
IPS WATER CONNECTION
(2” x
1/2” x
2”)
MAY
CHILLED WATER THERMOSTAT
The chilled water thermostat is mounted inside the unit
FIGURE 7.
FIELD INSTALLED
I
L
FIGURE 8.
OOLER WITH 2” IPS CONNECTION
”
IPS
45’
ELBOW
BASE FRAME
2” IPS WATER PIPE
THERMOSTAT SENSOR INSTALLATION
control center. The sensor must be installed in the return
water line as shown in Figure 8. The thermostat sensor
should be insulated after installation.
REDUCING TEE
THERMOSTAT
12”~ l/Z” x 2”)
BULB
W
FIELD INSTALLED
CAUTION: Thermostats have maximum operating
temperature limits of
125OF on return water. Temperatures
exceeding these limits may damage the controls.
ETURN
WATER
THERMOSTAT SENSO EVAPORATOR
RETURN WATER
LINE
CONNECTION OF
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FLOW SWITCH
A water flow switch or pump starter interlock is required to
insure that there will be adequate water flow and cooling
load to the evaporator before the unit can start. This will
safeguard against slugging the compressors on start-up. It
also serves to shut down the unit in the event that water
flow is interrupted to guard against evaporator freeze-up.
A flow switch is available from
ordering number 860-175033X-00. It is a “paddle” type
switch and adaptable to any pipe size from l-inch to 6-inch
nominal. Certain minimum flow rates are required to close
McQUAY
under
the switch and are listed in Table 4. Installation should be
as shown in Figure 9.
Electrical connections in the unit control center should
be made at terminals 12 and 21. The normally open
contacts of the flow switch should be wired between these
two terminals. There is also a set of normally closed
contacts on the switch that could be used for an indicator
light or an alarm to indicate when a “no flow” condition
exists.
TABLE 4. FLOW SWITCH MINIMUM FLOW RATES
NOMINAL
PIPE SIZE
(INCHES)
1
l/4
1
1/2
2
MINIMUM REQUIRED
FLOW TO ACTIVATE
SWITCH (GPM)
9.80
12.70
18.80
FIGURE 10. DIMENSIONAL DRAWING
68.60 OPENING (AIR
WATER CONN.
CLEARANCE HOLES
3.62 DIA.
(2)
OUTLET SCREEN
NOT SHOWN)
-
FIGURE 9.
FLOW SWITCH
NO RESTRICTIONS
5
PIPE DIAMETERS MIN.
AFTER SWITCH
FLOW DIRECTION
MARKED ON SWITCH
NO RESTRICTIONS
5 PlPE DIAMETERS MlN
BEFORE SWITCH
(FIELD MOUNTED)
OPTIONAL
PAGE 6
#
14.761
LIFTING HOLES
2.50 DIA.
(2
EACH SIDE)
MOUNTING HOLES,
.750 DIA. (2 EACH
SIDE)
ALR
UNIT SIZE
012A-S
015A-S
020A-S
025AS
030A-S
POWER CONN.
J
/
k
46.00
MOUNTING HOLES
DIMENSIONS & CONNECTIONS
A
50.60
50.60
65.60
65.60
80.60
DIMENSIONS (INCHES)
B
48.88,
Inlet
36.88,
Inlet
36.88, Inlet
36.88, Inlet
Outlet
14.02,
C
7.20,Outlet
7.20.
Outlet
7.20,
Outlet
7.20,Outlet
18.06, Inlet
WATER CONN. SIZE
2”I.P.S.
2”I.P.S.
I
.P.S.
2”
2”I.P.S.
2”
I
.P.S.
Page 7
REFRIGERANT
ADDING REFRIGERANT CHARGE
On systems that have been previously charged with
refrigerant, an insufficient charge is indicated by bubbling
in the sightglass. On uncharged systems the system should
be leak tested and evacuated before charging.
Upon charging a system the discharge and suction
shut-off valves on the compressor should be open and there
should be normal water flow through the cooler.
CAUTION: Do not make any safety controls
inoperative during the charging operation; cooler damage
from freezing may result.
Back seat the liquid line shut-off valve and connect the
1.
charging hose to the
2.
Install pressure gauges and review start-up instructions.
3.
Purge the charging hose and open the charging cylinder
to allow refrigerant into the system.
When removing the refrigerant on water chiller systems to
prevent freeze-up, either drain the water or circulate the
water. If water cannot be drained, make sure the cooler
heater is energized; do not remove refrigerant rapidly since
this can cause freeze-ups. Have a sufficient number of
refrigerant containers at hand and a scale for weighing
them. The containers should be clean, dry and empty.
To transfer the refrigerant to a container connect the
gauge manifold from the compressor discharge valve service
port to the container and purge the lines. Note the capacity
l/4-inch
flare connection.
REMOVING REFRIGERANT CHARGE
4.
Turn the liquid line shut-off valve in three turns to
permit a back flow of refrigerant into the subcooler.
After refrigerant stops flowing into the system, close
5.
the liquid line shut-off valve. Start the compressor to
charge the system.
6.
If the amount of refrigerant has been predetermined,
add this amount and check the sightglass afterward. If
the amount of charge is unknown, every five minutes
close the charging cylinder valve, open the liquid line
shut-off valve and check for proper charge by
examining the sightglass. Continue charging and
checking the sightglass until it
NOTE: Fluorocarbon refrigerants should not be
released to the atmosphere. For a means
to the following section.
of the container. Place the container in ice to cool the
container so the fusible plug does not melt as the condenser
condenses. Operate the compressor normally. Turn the
discharge service valve in three turns to open the service
port. Open the container valve and the gauge manifold. Do
not close off the discharge valve to the condenser; discharge
gas can enter the container and condense. Frequently weigh
the container so as not to overfill. When the container is
filled use additional ones.
clears.
I
of
recovery, refer
FIELD WIRING
Wiring should be done in accordance with all applicable
codes and ordinances. Warranty is voided if wiring is not in
accordance with specifications. An open fuse indicates a
short, ground or overload. Before replacing a fuse or
restarting a compressor or fan motor, the trouble must be
found and corrected.
Copper wire is required for all power lead terminations
at the unit.
All unit sizes are set up as standard for separate 115
volt power supply circuits for the control circuit and cooler
heater. The control circuit only, or both the control circuit
-
and the cooler heater, can be powered off the main unit
power supply if the optional control circuit transformer is
ordered. It may be desirable, however, to have the unit
cooler heater on a separate disconnect switch from the
main unit power supply so that the unit may be shut down
without defeating the freeze protection provided by the
cooler heater.
A standard feature on all ALR units is COPS
(Controlled Override of Pump Shut-down), a system for
interlocking
chiller control system. Relay RI9 is wired into the unit
control circuit so that a time clock and/or ambient
thermostat can be connected to a pair of terminals (14 and
15) inside the unit control center. The time clock can
energize a pump starter. Once the pump starts, the flow
switch and/or pump interlock will close and energize that
part of the control circuit that will allow the unit to start.
This feature makes it possible to start the chilled water
pump and the chiller simultaneously only when cooling is
required. For recycling
cooling, a relay (energized by the low pressure control) is
also wired into this circuit to start the pump, close the flow
switch and pump down the unit.
NOTE: If a time clock, ambient thermostat and/or
remote on-off switch are not used, terminals 14 and 15
must be
Figure 11 shows typical field wiring that is required for
unit installation.
2. Compressor rated load amps are for wire sizing purposes only
3. Compressor locked rotor amps for part-winding start is for the
ACROSS-THE-LINE-START
do not reflect normal operating current draw.
LOCKED ROTOR AMPS
PART-WINDING-START
COMPRESSOR
228 _
228
114
114
308 188
308 188
154 _
154 _
428 250
428 250
214 _
214
470 292
470 292
235
235 _
565 340
565 340
283 _
283
COMPRESSOR
_
_
-
and
START-UP & SHUT-DOWN
PRE START-UP
With all electric disconnects open, check all screw or lug
1.
type electrical connections to be sure they are tight for
good electrical contact. Check all compressor valve con-
nections for tightness to avoid refrigerant loss at startup. Although all factory connections are tight before
shipment, some loosening may have resulted from ship-
ping vibration.
2.
Inspect all water piping for flow direction and correct
connections at the evaporator.
3.
Open all water flow valves and start the chilled water
pump. Check all piping for leaks and vent the air from
the evaporator as well as from the system piping. Flush
the evaporator and system piping to obtain clean,
non-corrosive water in the evaporator circuit.
4.
Check to see that the thermostat water temperature
sensor is installed in the return water line (return to
chiller). The sensor well should be full of heat
conducting compound and the sensor should be secured
in the well with the retaining clip provided.
5.
Check the compressor oil level. Prior to start-up, the oil
level should cover at least
6.
Check the voltage of the unit power supply and see that
it is within the
*IO%
voltage unbalance must be within 42%.
7.
Check the unit power supply wiring for adequate
ampacity and a minimum insulation temperature rating
of 75c.
8.
Verify that all mechanical and electrical inspections
have been completed per local codes.
1/2
of the oil sightglass.
tolerance that is allowed. Phase
9.
See that all auxiliary control equipment is operative and
that an adequate cooling load is available for initial
start-up.
10. Making sure control stop switch
pumpdown
pumpdown,”
switches PSI and PS2 are on “manual
throw the main power and control discon-
S1
is open (off) and
nect switches to “on.” This will energize the crankcase
heaters. Wait a minimum of 12 hours before starting
unit.
CAUTION: Most relays and terminals in the unit control center are hot with
connect on.
S1 and the control circuit dis-
START-UP
Double check that the compressor suction and dis-
1.
charge shut-off valves are back seated. Always replace
valve seal caps.
Open the manual liquid line shut-off valve at the outlet
2.
of the subcooler.
Allow the crankcase heater to operate for at least eight
3.
hout
s
prior to start-up.
Check to see that the
4.
“manual pumpdown”
switch
5.
Adjust the dial on temperature controller
(S1)
is in the “on” position.
pumpdown
position and the control stop
desired chilled water temperature.
Start the auxiliary equipment for the installation by
6.
turning
on the time clock, ambient thermostat and/or
switch PSI is in the
TC1
to the
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Page 10
remote on/off switch if the unit and chilled water pump
are electrically interlocked by using the COPS method
discussed in “Field Wiring.”
Start the system by moving pumpdown switch PSI to
the “auto. pumpdown” position.
After running the unit for a short time, check the oil
level in each compressor crankcase and check for flashing in the refrigerant sightglass (see “Maintenance”).
After system performance has stabilized, it is necessary
that the “Compressorized Equipment Warranty Form”
(Form No. 206036A) be completed to obtain full warranty benefits. This form is shipped with the unit and
after completion should be returned to
Service Department through your sales representative.
TEMPORARY SHUTDOWN
If the unit is equipped with COPS switching devices (see
Typical Field Wiring Diagrams, page IO), open the switch.
If not, proceed as follows:
Move pumpdown switch PS1 to the “manual pumpdown” position. After the compressors have pumped down,
turn off the chilled water pump.
NOTE: With the unit left in this condition, it is capable
of recycling
operation, move control stop switch
tion.
It is important that the compressors pump down before
the water flow to the unit is interrupted to avoid freeze-up
in the evaporator.
pumpdown
operation. To defeat this mode of
S1
to the “off” posi-
McQuay’s
START-UP AFTER TEMPORARY SHUTDOWN
If the unit is equipped with COPS switching devices (see
Typical Field Wiring, page IO), open the switch. If not
proceed as follows:
1. Start the chilled water pump.
2. With control stop switch
pumpdown switch PSI to the “auto. pumpdown” position.
3. Observe the unit operation for a short time to be sure
that the compressor does not cut out on low oil
pressure.
EXTENDED SHUT-DOWN
Close the manual liquid line shut-off valve.
1.
2.
After the compressor has pumped down, turn off the
chilled water pump.
Turn off all power to the unit and to the chilled water
3.
pump.
4.
Move the control stop switch
5.
Close the compressor suction and discharge valves.
6.
Tag all opened disconnect switches to warn against
start-up before opening the compressor suction and
discharge valves.
7.
Drain all water from the unit evaporator and chilled
water piping if the unit is to be shut down during
freezing temperatures.
8.
If water is not drained during freezing temperatures
leave power to cooler heater on.
S1
in the “on” position, move
S1
to the “off” position.
ELECTRICAL
CONTROL CENTER
All electrical controls are enclosed in a weatherproof
control center
Figure
12). The
The left section is the largest and contains all of the 208,
230, 380 or 460 volt compressor and fan motor starting
controls. Also included in this section but partitioned
separately are the exposed terminal type, 115 volt
operational controls. A “dead front” cover over the left
section protects service personnel from high voltage starting
controls and exposed terminal operational controls.
The right section, not covered by the “dead front”
panel, contains 115 volt adjustable or resettable controls.
Power supply conduits are intended to come into the
bottom of the control center. It is recommended that the
unit disconnect switch be mounted away from the unit.
However, Figure 12 shows a recommendation for unit
mounting arrangements if the disconnect must be unit
mounted.
with
a keylocked, hinged access door (see
control center is composed of two sections.
-
FIGURE 12.
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SEQUENCE OF OPERATION
The following sequence of operation is typical for the single
compressor ALR SEASONPAK air cooled water chiller.
With control circuit power on, control stop switch
closed and manual
pumpdown
switch
PS1
closed (“auto”
position), 115 volt power is applied through control circuit
fuse
Fl
to the compressor crankcase heater
HTR1
to the contacts of low pressure switch LPI.
When the remote time clock or manual shut-down
switch turns “on”,
COPS pump starter relay RI9 is
energized, closing contacts 1 and 3 to start the chilled water
pump. Relay
R19
contacts 4 and 6 in the thermostatic
circuit also close. With the flow switch closed and if freeze
control
FS1
high pressure control
OP1
(not on
MP1
do not sense an alarm condition, safety relay R5 is
energized,
controller
response to
For ALR-012
control thermostat
SV1
opening the valve and allowing refrigerant to flow into
ALR-012A),
and compressor motor protector
applying power to the water temperature
TC1
The unit will operate automatically in
TC1.
-
On a call for cooling, temperature
TC1
energizes liquid line solenoid valve
HP1
oil pressure control
the evaporator. As refrigerant pressure builds up, low
pressure control
LP1
closes, energizing low pressure relay
R9 which closes to energize time delay TD14. TD14 closes
to energize fan motor relay Ml 1, closing its contacts and
providing power to condenser fan motor contacts Ml 1,
Ml2 and M13. On a drop in return water temperature, stage
2 of thermostat
TC1
closes, relay R21 is energized and
normally open contact R21 is closed. Relay Ml is energized
and normally closed Ml AUX contacts are open.
Compressor contactor Ml is closed and the compressor is
running at slow speed. On a rise in return water
temperature, stage 2 of thermostat
TC1
opens, relay R21 is
de-energized and normally closed contact R21 is closed.
Relay
M9
is energized and normally open contact M9 is
closed. Compressor contactors M5 and M9 are closed and
the compressor is running at fast speed.
For ALR-015, 020, 025, 030
temperature control thermostat
solenoid valve
SV1
opening the valve and allowing
-
On a call for cooling,
TC1
energizes liquid line
refrigerant to flow into the evaporator. As refrigerant
pressure builds up, low pressure control LPI closes,
energizing low pressure relay R9 which closes to energize
S1
and also
compressor contactor M 1, starting the compressor. Closing
relay R9 contacts also energizes condenser fan relay Ml 1,
closing its contacts and providing power to condenser fan
motor contactors Ml 1, Ml2 and M13. On a drop in return
water temperature,
stage 2 of thermostat
TC1
closes.
Unloader U1 is then energized and the compressor
unloads. On a rise in return-water temperature, stage 2 of
thermostat
TC1
opens. Unloader U1 is de-energized and the
compressor is loaded.
PUMPDOWN CYCLE
As temperature control thermostat
its contacts, de-energizing liquid line solenoid valve
TC1
is satisfied, it opens
SV1
causing the valve to close. When the compressor has
pumped most of the refrigerant from the evaporator to the
condenser, the low pressure control LPI opens, shutting
down the compressor and condenser fan motors.
Should a closed solenoid valve allow refrigerant to leak
to the low side of the refrigerant circuit during unit “off”
time, the build-up in pressure will cause the low pressure
control to close, energizing the low pressure relay and
starting the compressor for pumpdown.
MAJOR COMPONENT LOCATIONS
ALR-012A-S, 015A-S, 020A-S, 025A-S
REAR VIEW OF UNIT
COIL ON OPPOSITE SIDE
NOTE
CONDENSER FAN 11 IS LOCATION OF OPTIONAL
SPEEDTROL MOTOR.
&
030A-S
4
-
PAGE 12
MODEL
NUMBER SIZE
ALR-012A-S12 Ton
ALR-015A-S
ALR-OPOA-S 25
ALR-025A-S30
ALR-030A-S35HP
COMPRESSOR
20
HP3/43/43/4
HP
HP3/4
MAJOR COMPONENTS
FAN HP
11
3/4
3/4
3/43/43/4
I
12
3/4
3/4
3/4
I
13 DIA. xLENGTH
3/4
3/48”x
3/4
COOLER SIZE
6”x 48”
6”x60”
60”
8”x60”
8”x72”
_
Page 13
Page 14
Page 15
Page 16
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Page 18
CONTROLS
OIL PRESSURE SAFETY CONTROL
ALR-015A, 020A, 025A, 030A (NOT ALR-012A)
The oil pressure safety control is a manually resettable
device which senses the differential between oil pressure at
the discharge of the compressor oil pump and suction
pressure inside the compressor crankcase. When the oil
pressure reaches approximately 15 PSI above the crankcase
suction pressure, the pressure actuated contact of the
control opens from its normally closed position. If this
pressure differential cannot be developed, the contact will
remain closed and energize a heater element within the
control. The heater element warms a normally closed
bimetallic contact and causes the contact to open,
de-energizing a safety relay and breaking power to the
compressor.
It takes about 120 seconds to warm the heater element
enough to open the bimetallic contact, thus allowing time
for the pressure differential to develop.
If during operation the differential drops below
the heater element will be energized and the compressor
will stop. The control can be reset by pushing the reset
button on the control. If the compressor does not restart,
allow a few minutes for the heater element and bimetallic
10
PSI,
contacts to cool and reset the control again.
To check the control, pump down and shut off all
power to the unit. Remove the compressor relay wiring at
terminals 2 and 8, jumper across terminals L and M of the
freeze control and install a voltmeter between terminals L
and M of the oil pressure control. Turn on power to the
unit control circuit (separate disconnect or main unit
disconnect, depending on the type of installation). Check
to see that the emergency stop switch
S1
is in the “on”
position. The control circuit should now be energized, but
with the absence of the compressor running no oil pressure
differential can develop and thus the pressure actuated
contacts of the control will energize the heater element and
open the bimetallic contacts of the control within 120
seconds. When this happens the safety relay is de-energized,
the voltmeter reading will rise to 115V and the compressor
contactor should open. Repeated operations of the control
will cause a slight heat build-up in the bimetallic contacts
resulting in a slightly longer time for reset with each
successive operation.
LINE (SEE NOTE 1)
CONTACT
LINE (SEE NOTE
NOTES: 1. Hot only when the unit thermostat calls for compressor
2)
to run.
2. Hot only when other safety control contacts are closed.
T2 120
L M
41
BIMETALLIC CONTACTS
-
*
t
HEATER ELEMENT
SAFETYRELAY
NOTE: PERFORM AN OPERATIONAL CHECK ON ALL UNIT SAFETY CONTROLS ONCE PER YEAR.
SOLID STATE COMPRESSOR MOTOR PROTECTION
If the compressor has been operating and has been
All air cooled water chillers have compressors with solid
state motor protection. Both Robertshaw and Texas
Instruments systems are used and their components are not
interchangeable.
There are two major components in a protection
system. First, the protector sensors are mounted internally
in the motor windings. The sensors monitor winding
temperature. A change in temperature causes a change in
sensor resistance. Sensor resistance is monitored by the
second component of the system
-
the control module
which is a sealed enclosure containing a relay, transformer
and other electronic components. Leads from the sensors
are connected to the module. Sensor resistance triggers the
control module relay at definite opening and closing
settings.
The module voltage will always be 120V and will be so
marked. When the control module needs repair no attempt
should be made to repair it. It should be returned intact for
replacement. If the module is opened or physically
damaged the warranty is void.
The control module and solid state sensor can be
damaged by high voltage. A high potential test should never
be made to the module or sensors.
If the compressor motor is not operating properly the
following procedure may be used to check the solid state
motor control circuit.
PAGE 18
1.
stopped by the motor protector, allow one hour for the
compressor to cool and the motor protector to reset.
2. If reset does not occur connect a jumper wire across the
motor protector from terminal 30 to 36. If the
compressor does not operate with the jumper installed
the problem is not within the solid state protector
system. If the compressor operates with the jumper
installed and does not operate without the jumper the
control circuit relay in the module is open for some
reason.
CAUTION: Only check compressor operation with
jumper installed. Do not continue operation.
A possible cause of the open relay is the motor sensors.
They may be checked by first removing the connections to
the terminal board. Use an ohmmeter of 3 volt maximum
voltage to check resistance from each sensor terminal to the
common terminal. No voltage or current should be applied
to the sensors to check continuity. The resistance across
each motor sensor should be approximately 500 to 2400
ohms with a motor temperature below
Instruments system. For the Robertshaw protector the
resistance across each sensor should be 75 ohms (cold) to
125 ohms (hot). If the resistance is zero there is a short.
the resistance is infinity there is an open connection.
NEUTRAL
NEUTRAL
140°F
for the Texas
If
Page 19
On reset the resistance of the sensors must be below the
reset point before the relay contacts will close. The reset
resistances are 90 ohms for Robertshaw and 2700 to 4500
ohms with Texas Instruments.
If the sensor resistance has been checked and found to
be satisfactory and the compressor will run with the control
bypassed but will not run with the control wired properly,
the control module is defective and must be replaced.
In case the resistance across a sensor is infinity the
module will prevent compressor operation. As an emergency
means of obtaining compressor operation until the compressor can be replaced, a resistor may be added between
the terminal of the open sensor and the common terminal
in the terminal box. The control module then “sees” an
acceptable resistance and compressor operation will be
restored. The emergency resistor should be as follows:
Robertshaw
Texas Instruments - 1 watt, 2200 ohm
The emergency resistor will not provide the same degree of
protection, but it provides a reasonable measure of safety.
The high pressure control is a single pole pressure activated
switch that opens on a pressure rise to de-energize the
entire control circuit except for compressor crankcase
heater and the cooler heater. It senses condenser pressure
and is factory set to open at 380
reset closed at 315 PSIG. To check the control block off
condenser surface and observe the cut-out point of the
-
2 watt, 82 ohm
15%
resistor.
ItlO%
resistor.
HIGH PRESSURE CONTROL
PSIG and can be manually
SENSOR
CIRCUIT
r----
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.k
L-I- L-J
i/r---t”-
J
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r--l
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1
0
SENSORS
SOLID STATE MODULE
r-
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,
I
control by watching condenser pressure rise. The highest
point reached before cut-out is the cut-out setting of the
control.
CAUTION: Although there is an additional pressure
relief device in the system set at 425 PSIG, it is highly
recommended that the control stop switch
hand in case the high pressure control should malfunction.
S1
be close at
LOW PRESSURE CONTROL
The low pressure control is a single pole pressure switch
that closes on a pressure rise. It senses evaporator pressure
and is factory set to close at 60 PSIG and automatically
open at 35 PSIG. To check the control (unit must be
running), move the
pumpdown” position.As the compressor pumps down
condenser pressure will rise and evaporator pressure will
The thermostats supplied on all packaged chillers are
factory calibrated for use in the return water line to the
cooler inlet. The thermostat bulb is installed in a well in the
return water line in order to be more stable under
temperature changes due to load conditions. The return
water does not change temperature as rapidly as the outlet
because of the “flywheel effect” of the total water system.
This results in stable control of the outlet water
temperature. Normally the thermostat requires no
adjustment in the field other than the dial setting for the
required control point. The control is preset at the factory
to maintain a 44F average leaving water temperature
throughout the loading and unloading sequence of the unit,
based on a full load cooling range of
realized, however, that there will be a fluctuation in the
leaving water temperature as the unit cycles, unloads and
loads. The thermostat will provide satisfactory control over
a chilled water range of 8
special controls will be required to provide best system
performance.
On a two-stage thermostat, the dial setting indicates the These settings may be checked by operating the unit
average leaving water temperature that the control will and slowly reducing the load. The four-stage thermostat has
maintain. At a 44F setting, the high stage should open at a fixed switch differential and fixed differential between
approximately 51 F return water. The low stage will open at switches. DO NOT make any adjustments other than the
46F return. As the water warms up, the low stage should dial as this is a preset precision control.
pumpdown
- 12’F.
switch PSI to the “manual
THERMOSTAT
10F.
It should be
Beyond these extremes
drop. The lowest evaporator pressure reached before
cut-out is the cut-out setting of the control. By moving the
pumpdown
evaporator pressure will rise. The highest evaporator
pressure reached before compressor restart is the cut-in
setting of the control.
cut in at approximately 49F which is the inlet and outlet
temperature with the unit off; the high stage should close at
54F return.
These settings may be checked by operaing the unit and
slowly regulating the load from full to minimum and
return. It may then be necessary to adjust the dial and/or
differential between switches to obtain these values.
is slow; consequently, approximately 5 minutes must be
allowed for bulb response (after attaining system
steady-state operation) before any or each adjustment to
thermostat is made.
the cut-in point of the first stage. With the dial set at
46-1/2’F,
second stage at
fourth stage at
stage will open at a return water temperature of
the third stage at
the unit will shut off at
switch PSI to the “auto. pumpdown” position,
CAUTION: Response time on the two-stage thermostat
On the four-stage thermostat the dial setting indicates
the first stage will actuate at
49’F,
the third stage at
54’F.
On a temperature drop the fourth
49’F,
the second stage at
44’F
return water.
46-1/2’F,
51-1/2’F
46-1/2’F
the
and the
51-1/2’F,
and
PAGE 19
Page 20
FREEZE CONTROL
The freeze control is very similar to the oil pressure control
in operation except that it senses evaporator pressure only
rather than a pressure differential. It contains a pressure
activated contact that upon a fall in evaporator pressure
energizes a heater element that in turn opens a normally
closed bimetallic contact. When the bimetallic contact
opens, it de-energizes the entire control circuit except for
the compressor crankcase heaters and cooler heater. The
control is factory set to close at 52 PSIG and open at 54 to
PSI to the
pressure will
zero, the pressure activated contacts of the control will
have closed. Note the evaporator pressure at which this
happens. Because the unit will have pumped down before
the 60 second delay period, bimetallic contacts L and M
will not open before the unit shuts down. This part of the
control operation may be checked after the pumpdown
cycle is complete by connecting a jumper from terminal 13
“manual pumpdown” position. Evaporator
begin
to drop. When the voltmeter goes to
57 PSIG. It takes approximately 60 seconds to warm the in the control center to terminal T2 of the control. This
heater element enough to open the bimetallic contact. This
will energize the heater element of the control provided
time delay period prevents nuisance cut-outs due to a that evaporator pressure is sufficiently low. Within about
momentary drop in suction pressure, but since the control 60 seconds, the bimetallic contacts of the control should
senses pressure rather than temperature it still provides
quicker response for protection than a temperature sensing
open.
Should the control cause the unit to shut down during
control. normal operation, a period of about 2 minutes will be
To check the control, the system must be operating. A required before the bimetallic contacts of the control will
voltmeter should be connected across terminals of the have cooled enough to allow the control to be manually
pressure activated contact. With the unit running, there
reset. Similar to the oil pressure safety control, repeated
should be a 115 volt potential across these terminals. successive operations of the freeze control will prolong the
Observing evaporator pressure, move the pumpdown switch
LINE (SEE NOTE
LINE
(SEE NOTE 2)
1)
PRESSURE
ACTUATED
CONTACT
L M
XI
time required before reset.
120
HEATER ELEMENT
BIMETALLIC CDNTACT
NEUTRAL
LINE (SEE NOTE
3)
NOTES: 1. Hot whenever unit compressor is running.
2. Hot whenever control circuit flow switch and control stop
switch
(S1)
3. Provides power to energize compressor contactors through
low pressure relay
are closed.
(R9).
FANTROL - HEAD PRESSURE CONTROL
FANTROL is a system for progressively turning on or off
condenser fans when they are no longer required. This is
done to reduce condenser capacity (typically in low
outdoor ambient temperatures) and is accomplished by a
combination of pressure and temperature actuated controls.
The first fan (No. 11) is started by its contactor when the
compressor in the unit starts. The second fan (No. 12) is
controlled by a pressure switch which senses condenser
pressure.
The third fan (No. 13) is controlled by a
temperature switch which senses condenser air inlet
temperature. Pressure and temperature control set points
are indicated below.
CONDENSER
FAN NUMBER
11
12 270 PSIG170 PSIG
13
CUT-IN
WITH COMPRESSOR WITH COMPRESSOR
8OF
CUT-OUT
70F
To check the cut-in points of the controls, the unit
must initially be off. With the unit prepared for start-up
according to the procedures outlined in this bulletin, move
pumpdown switch PSI to the “auto. pumpdown” position.
Evaporator pressura will begin to rise and the compressor
should start with Fan 11 starting immediately. After the
compressor starts, observe condenser pressure as it rises.
When the condenser pressure reaches approximately 270
PSIG, contactor Ml2 should pull in to start Fan 12. Fan 13
should start via contactor Ml3 whenever the ambient air at
the condenser inlet reaches 80F.
It may be difficult to check the cut-out point of Fan 13
at the instant it happens, but it should be off whenever the
ambient air at the condenser inlet is below 70F. To check
the cut-out point of Fan 12, some means of reducing the
load on the unit must be available or the fan operation and
condenser pressure must be observed as the load drops off
naturally. When the condenser pressure drops to
approximately 170 PSIG, contactor Ml2 should drop out
to turn off Fan 12.
_
PAGE 20
Page 21
OPTIONAL CONTROLS
SPEEDTROL (OPTIONAL)
McQUAY’s
backside of the control center, continuously varies No. 11
condenser fan motor speed on air cooled condensers by
sensing changes in refrigerant head pressure. SPEEDTROL
makes possible unit operation
temperatures.
With an increase
SPEEDTROL increases fan motor speed. With a decrease in
pressure fan motor speed is decreased.
The pressure connection of the transducer is made to the
high pressure side of the refrigeration system at the purge
valve connection on the condenser coil header. This
transducer coupled with a solid state unit modulates the
solid state SPEEDTROL, located on the
in lower ambient
in refrigerant head pressure
PART WINDING START (OPTIONAL)
Part winding start consists of a solid state time delay wired
in series with the contactor that energizes the second
winding of each compressor motor. Its purpose is to limit
current in-rush to the compressors upon start-up. As each
compressor starts, the contactor for the first motor winding
LINE
PART WINDING
phase conduction angle of the AC sine wave supplied to the
fan motor. The fan motor is a special
SPEEDTROL motor. For 460 volt units a transformer is
supplied to decrease line voltage to 230 volt motor voltage.
The SPEEDTROL controller is calibrated to deliver 90% of
line voltage at the
effective throttling range of 60 PSIG which is the decrease
in pressure below the calibration
supply voltage is transmitted to the motor. When 45% of
supply voltage is transmitted to the motor, minimum motor
speed is reached; below this point there is no change in
speed.
is energized instantly, while that for the second motor
winding is delayed for one second.
Control checkout is best accomplished by observation
as each contactor is pulled in to see that the one-second
delay occurs before the second contactor pulls in.
setpoint
pressure of 230 PSIG. It has an
setpoint
208/230V
where 45% of
LOW AMBIENT START (OPTIONAL)
Low ambient start is available on all units as an option with
FANTROL and included automatically with optional
SPEEDTROL. It consists of a solid state normally closed
time delay wired in series with a relay. These are both wired
in parallel to the liquid line solenoid valve so that when the
solenoid valve is energized by the unit thermostat, the low
ambient start relay is also energized through the time delay.
The relay has contacts that essentially short circuit the low
pressure control and allow the compressor to start with the
low pressure control open.
After about
de-energize the relay. If the system has not built up enough
evaporator pressure to close the low pressure control, the
compressor
original normally closed position by moving the
switch PSI to the “manual pumpdown” position. Moving
2-3/4
minutes, the time delay will open and
will stop. The time delay can be reset to its
pumpdown
(2nd MOTOR WINDING)
the
pumpdown
position will again energize the relay for another attempt at
start-up.
pressure, the compressor will continue to run.
To check the control, turn off all power to the unit and
remove the wire leading to the low pressure control LPI
from terminal 11 in the unit control center. Remove the
wires leading from the contactors to the compressor and
jumper across terminals L and M of the freeze control and
oil pressure safety control. Energize the control circuit by
turning on the control circuit disconnect or main power
disconnect (depending on the installation) and the control
stop switch
instantly. After about
again.
switch back to the “auto. pumpdown”
If the system has built up enough evaporator
S1
The compressor confactors should pull in
2-3/4
minutes they should drop out
NOTE:
Line is only hot when the unit thermostat calls for
compressor to run.
PAGE 21
Page 22
COMPRESSOR LOCKOUT (OPTIONAL)
Compressor lockout consists of a solid state time delay pumpdown”
wired in series with the compressor
purpose is to prevent rapid compressor cycling when
cooling demands are erratic.
contactor(s)
its
has stopped running, move the
the “auto. pumpdown” position. The compressor should
not restart for five minutes.
When the unit thermostat no longer calls for cooling
and the compressor
contactor(s)
have opened, the lockout
time delay breaks open the circuit preventing compressor
restart.
The circuit remains open for a period of five minutes so
that if the unit thermostat should call for cooling before
the delay period has expired, the compressor will not
restart. After five minutes the time delay will close its
contacts to complete the circuit and be ready for start-up.
The time delay opens its contacts whenever there is power
to the terminals of the compressor relay and resets closed
automatically after the time delay period.
To check the control, the compressor must be running
initially. Move the
In most cases, the customer will want to locate the alarm
bell where it will be heard in the event of a safety failure.
After mounting the bell should be wired to the transformer
T4.
pumpdown
switch PSI to the “manual
ALARM BELL (OPTIONAL)
When the bell is wired into the control circuit, it will
sound whenever there is a failure due to low oil pressure
(not on
ALR-012A),
condition, or excessive condenser pressure.
HOT GAS BYPASS (OPTIONAL)
Hot gas bypass is a system for maintaining evaporator
pressure at or above a minimum value. The purpose for
doing this is to keep the velocity of the refrigerant as it
passes through the evaporator high enough for proper oil
return to the compressor when cooling load conditions are
light.
The system consists of a solenoid valve piped in series
with a pressure regulating valve as shown above. The
solenoid valve is factory wired to open whenever the unit
thermostat calls for the first stage of cooling. The pressure
regulating valve is factory set to begin opening at 58 PSIG
(32F
for R-22) when the air charged bulb is in an 80F
ambient temperature. Since the bulb is factory mounted on
the suction line and suction line temperatures are usually in
the 50F to 60F range, the chart above indicates that for
ALR chillers the valve is factory set to begin opening at 54
to 56 PSIG. This setting can be changed as indicated above
by changing the pressure of the air charge in the adjustable
bulb. To raise the pressure setting, remove the cap on the
bulb and turn the adjustment screw clockwise. To lower the
setting, turn the screw counter-clockwise. Do not force the
adjustment beyond the range it is designed for as this will
damage the adjustment assembly.
The regulating valve opening point can be determined
by slowly reducing the system load (or increasing the
required chilled water temperature setting indicated on the
unit thermostat) while observing the suction pressure. When
the bypass valve starts to open, the refrigerant line on the
evaporator side of the valve will begin to feel warm to the
touch.
CAUTION:
cause injury in a very short time so care should be taken
during valve checkout.
position. Immediately after the compressor
pumpdown
1’
COMP.
TIME DELAY
TO UNIT THERMOSTAT
switch back to
LOCKOUl
motor overload, and evaporator freeze
The hot gas line may become hot enough to
_
HOT GAS BYPASS PIPING DIAGRAM
Hot Gas Bypass
Solenoid Valve
\~
L
Discharge Line
PAGE 22
/e
.&lot
Gas
Bypass Valve
I~- Suction Line
Remote Bulb
k-To
Evaporator
Inlet After
Expansion Valve
HOT GAS BYPASS ADJUSTMENT RANGE
REMOTE
BULB ADJUSTMENT RANGE
311
70
6C
50
40
30
30 40
50
60
TEMP IOFI
AT BULB LOCATION
73
8090
100
110
:’
I
L_
:;
5<
i
Page 23
UNIT MAINTENANCE
GENERAL
CAUTION: Disconnect all power before doing any service inside the unit.
On initial start-up and periodically during operation after ordered with gauges, condensing, suction and oil pressures
installation, it will be necessary to perform certain routine
service checks. Among these are checking the compressor
oil level and taking condensing, suction and oil pressure
readings. During operation the oil level should be visible in
the oil sightglass with the compressor running. On units taken.
REFRIGERANT SIGHTGLASS
The refrigerant sightglass should be observed periodically.
(A
monthly observation should be adequate.) A clear glass
of liquid indicates that there is adequate refrigerant charge
in the unit to insure proper feed through the expansion
valve. Bubbling refrigerant in the sightglass indicates that
the unit is short of refrigerant charge. An element inside the
FILTER-DRIERS
To change the filter-drier core, pump the unit down by
moving pumpdown switch PSI to the “man. pumpdown”
position. Turn off all power to the unit and install a jumper the filter-drier. Remove the cover plate from the filter-drier
from terminal 31 to 34. Turn power to the unit back on
and restart the unit by moving pumpdown switch PSI to
the “auto. pumpdown” position. Close the manual liquid check around the flange of the filter-drier shell is
line shut-off valve and when evaporator pressure reaches 0
PSIG, move the control stop switch
S1
to the “off”
can be read from the gauges. Oil pressure gauge is not
available on unit ALR-012A. The gauges are installed with a
manual shut-off valve on each gauge line. The valves should
be closed at all times except when gauge readings are being
sightglass is sensitive to moisture and a color key on the
face of the sightglass indicates what moisture condition
corresponds to a given element color. If the sightglass does
not indicate a dry condition after a few hours of operation,
the unit should be pumped down and the cores in the
filter-driers changed.
position. This will close the liquid line solenoid valve and
isolate the short section of refrigeration piping containing
shell and replace the core.
After core replacement, replace the cover plate. A leak
recommended after the core has been changed.
LlQUID
The liquid line solenoid valve, which is responsible for
automatic
not normally require any maintenance. It may, however,
require replacement of the solenoid coil or of the entire
valve assembly.
without opening the refrigerant piping by moving
pumpdown
Condensers are air cooled and constructed with
copper tubes bonded in a staggered pattern into rippled
aluminum fins. No maintenance is ordinarily required
except the occasional removal of dirt and debris from the
The oil level should be watched carefully upon initial
start-up and for sometime thereafter. At the present time,
Suniso 3GS oil is the only oil approved by Copeland and
Sundstrand for use in these compressors. The oil level
Oil may be added to the Copeland compressor through the
oil fill hole in the crankcase and to the Sundstrand
compressor through the
of the compressor. To add oil isolate the crankcase and
pour or pump the necessary oil in. If the system contains
no refrigerant, no special precautions are necessary other
than keeping the oil clean and dry.
suction valve and reduce crankcase pressure to 1 to 2 PSIG.
pumpdown
The solenoid coil may be removed from the valve body
switch PSI to the “manual pumpdown”
If the system contains a refrigerant charge, close the
during normal unit operation, does
3/8-inch
process tube on the side
LINE SOLENOID VALVE
CONDENSERS
3/8
O.D.
COMPRESSOR
ADDING OIL TO COMPRESSOR
position. The coil can then be removed from the valve body
by simply removing a nut or snap ring located at the top of
the coil. The coil can then be slipped off its mounting stud
for replacement. Be sure to replace the coil on its mounting
stud before returning pumpdown switch PSI to the “auto.
pumpdown” position.
To replace the entire solenoid valve, the unit must be
pumped down by use of the manual liquid line valve.
outside surface of the fins. Care should be taken not to
damage the fins during cleaning. Periodic use of the purge
valve on the condenser will prevent the build-up of
non-condensables.
OI L LEVEL
should be maintained at about the midpoint of the
sightglass on the compressor body. The use of a light may
be required for proper oil level reading.
Stop the compressor and close the discharge valve.
Add the required amount of oil. During the period the
compressor is exposed to the atmosphere the refrigerant
will generate a vapor pressure, retarding the entrance of
contaminants. Before resealing the compressor, purge the
crankcase by opening the suction valve slightly for one or
two seconds. Next, close the oil port, open the compressor
valves and restore the system to operation.
PAGE 23
Page 24
ELECTRICAL TERMINALS
CAUTION: ELECTRIC SHOCK HAZARD
-
TURN OFF ALL POWER BEFORE CONTINUING WITH
FOLLOWING SERVICE.
All power electrical terminals should be retightened every six months, as they tend to loosen in service
due to normal heating and cooling of the wire.
FAN MOTOR BEARINGS
All fan motors are pre-lubricated and do not require the addition of grease.
THERMOSTATIC EXPANSION VALVE
The expansion valve is responsible for allowing the proper
amount of refrigerant to enter the evaporator regardless of
cooling load. It does this by maintaining a constant
superheat. (Superheat is the difference between refrigerant
temperature as it leaves the evaporator and the saturation
temperature corresponding to the evaporator pressure.) All
ALR chillers are factory set for between 8F and 12F
superheat. If it is necessary to increase the superheat setting
of the valve, remove the cap at the bottom of the valve to
expose the adjustment screw. Turn the screw clockwise
(when viewed from the adjustment screw end) to increase
the superheat setting and counter-clockwise to reduce
superheat. Allow time for system rebalance after each
superheat adjustment.
The expansion valve, like the solenoid valve, should not
normally require replacement, but if it does, the unit must
be pumped down by using the manual liquid line shut-off
valve. If the problem can be traced to the power element
only, it can be unscrewed from the valve body without
removing the valve, but only after pumping the unit down
with the manual liquid line shut-off valve.
INLET
?v/AP7K
II
1
-A-----
POWER ELEMENT
(CONTAINS DIAPHRAGM)
t OUTLET
ADJUSTMENT SCREW
HYDRAULIC FILL
BETWEEN
DIAPHRAMS
-
PAGE 24
-
Page 25
EVAPORATOR
The evaporator is of the direct expansion, shell-and-tube
type with refrigerant flowing through the tubes and water
flowing through the shell over the tubes. The tubes are
internally finned to provide extended surface as well as
turbulent flow of refrigerant through the tubes. Normally
no service work is required on the evaporator. In the rare
case of freeze-up, a tube may leak refrigerant into the water
side of the system. In the cases where only one or two
tubes leak, the problem can best be solved by plugging the
tube at both ends. When the tube must be replaced, the old
tube can be removed and replaced.
To remove a tube, the unit should be temporarily
pumped down by moving
pumpdown
switch PSI to the
“man. pumpdown” position. Power to the unit should be
shut off to install a jumper from terminal 31 to 34. Turn
power to the unit back on. Pump down the refrigerant
circuit until evaporator pressure is at or near 0 PSIG by
closing the manual liquid line shut-off valve at the outlet of
the condenser. Close the compressor suction valve by
turning the valve stem clockwise. These steps will insure a
minimum amount of refrigerant loss when the
evaporator is
opened up. The tubes are mechanically expanded into the
tube sheets (see sketch above) at each end of the cooler. In
TOP VIEW OF TYPICAL SHELL-AND-TUBE EVAPORATOR
order to remove the tubes it is necessary to break this bond
by collapsing the tube. After doing this at both ends of the
shell, the tube can be removed for replacement. The new
tube can then be inserted and re-expanded into the tube
sheet.
NOTE: The bond produced by expansion must be
refrigerant tight. This bond must be produced by rolling the
tube into the tube sheet.
After re-assembling the evaporator, a small amount of
refrigerant should be introduced by momentarily opening
the manual liquid line valve. A leak check should then be
performed on the evaporator.
Tube removal can only take place after the leaking tube
is located. This aspect depends on the ingenuity of the
serviceman. One method that would work would be to
subject each tube to air pressure by plugging each end, and
with a pressure gauge attached to one of the end plugs,
observe to see if there is a loss of air pressure over a period
of a minute or two.
NOTE: The evaporator should always be supplied with
clean water to minimize scale build-up on the refrigerant
tubes.
LIQUID CONNECTION
SUCTION CONNECTION
REFRIGERANT TUBES
WATER BAFFLES
WATER NOZZLES
TUBE SHEETS
PAGE 25
Page 26
IN-WARRANTY RETURN MATERIAL PROCEDURE
COMPRESSOR
Bristol Corporation [compressor used in the
Copeland Corporation [all other units] have stocking
wholesalers who maintain a stock of replacement compressors and service parts to service refrigeration contractors
and servicemen,
When a compressor fails in warranty, contact your local
sales representative or McQuay Warranty Claims Depart-
ment at the address on the cover of this bulletin. You will
be authorized to exchange the defective compressor locally
(an advance replacement can be obtained), or we will ship
you a replacement from our stock. A salvage credit is issued
to you by the wholesaler on the returned compressor after
Material may not be returned except by permission of
authorized factory service personnel of McQUAY Inc. at
Minneapolis, Minnesota. A “Return Goods” tag will be sent
to be included with the returned material. Enter the
information as called for on the tag in order to expedite
handling at our factories and prompt issuance of credits.
The return of the part does not constitute an order for
replacement. Therefore, a purchase order must be entered
through your nearest McQUAY Representative. The order
ALR-012],
COMPONENTS OTHER THAN COMPRESSORS
and
Bristol or Copeland factory inspection of the inoperative
compressor. Provide McQuay with full details and invoices
and we will reimburse the difference. In this transaction, be
certain that the compressor is definitely defective. If a compressor is received from the field that tests satisfactorily, a
service charge plus a transportation charge will be charged
against the original credit value.
On all out-of-warranty compressor failures, Bristol and
Copeland offer the same field facilities for service and/or
replacement as described above. The credit issued by Bristol
or Copeland on the returned compressor will be determined
by the repair charge established for that particular unit.
should include part name, part number, model number and
serial number of the unit involved.
Following our personal inspection of the returned part,
and if it is determined that the failure is due to faulty
material or workmanship, credit will be issued on
customer’s purchase order.
All parts shall be returned to the pre-designated
McQUAY factory, transportation charges prepaid.
PAGE 26
Page 27
TROUBLE SHOOTING CHART
PROBLEM
Compressor
will not run.
Compressor noisy
vibrating.
or
High Discharge
Pressure
Low Discharge
Pressure.
High Suction
Pressure
Suction
Low
Pressure
Wi
Compressor
not unload
or load up.
Compressor
Loading -
Intervals too short
Little
oil pressure.
Compressor
loses
Motor overload
relays open or
fuses blown.
Compressor thermal
Protector Switch
open.
Freeze protection
opens.
II
Unloading
or no
oil.
POSSIBLE CAUSES
1.
Main switch
2. Fuse blown.
3. Thermal overloads
Defective
4.
5. System shut down by safety devices.
6. No
7. Liquid line solenoid
8. Motor electrical trouble.
9. Loose wring
1. Flooding of refrigerant into crankcase.
2. Worn compressor.
1. Dirty tube and fin surface.
2.
Non-condensables
3. System overcharged
4. Discharge shut off valve partially closed.
1. Faulty condenser temperature regulation.
Suction shutoff
2.
3.
Insufficient
4. Low suction pressure.
5. Compressor operating unloaded.
6. Low
1. Excessive load.
2. Expansion valve
3. Compressor unloaders open.
1. Lack of
2. Evaporator
3. Clogged liquid line filter-drw.
4. Clogged
gas strainers.
5. Expansion valve
6. condensing temperature too low.
7. Compressor will not unload.
8. Insufficient water flow.
1. Defective capacity control.
2. Unloader mechanism defectwe.
3. Faulty thermostat stage or broken capillary
tube.
4. Stages not set for
1. Erratic water thermostat.
2.
InsufficIent water
1. Clogged
2. Excessive liquid in crankcase.
3.
Oil
4. Low
5. Worn
6.
Oil
position
7. Worn bearings.
8. Low oil level.
9. Loose
10. Pump housing gasket leaks.
11.
Flooding
1.
Lack
2. Excessive
1. Low voltage during high load
2.
Defective
power
3. Loose power
4. High condensing temperature.
5. Power line fault causing unbalanced voltage.
6. High ambient temperature around the
overload relay.
7. Failure of second starter to pull in on
winding start systems.
1. Operating beyond design conditions.
2. Discharge valve partially shut.
3. Blown valve plate gasket.
1. Thermostat sat too low.
2. Low water flow.
3. Low
open.
tripped
or fuses blown.
contactor or coil.
cooling
required.
refrigerant in system.
ambient
refrigerant.
suction line
suction oil strainer.
pressure gauge defectwe.
oil
pressure safety switch defectwe.
oil
pump.
pump
reversing
fitting
of refrigerant into crankcase.
of refrigerant.
compression
or grounded wiring in motor or
circuits.
suction pressure.
will
not open.
in system.
with
refrigerant.
valve partially closed.
controls not set properly.
overfeedlng.
dirty.
or compressor suction
malfunctioning.
application.
flow.
gear stuck in wrong
on oil lines.
ring blow-by.
conditions.
wiring.
part-
POSSIBLE CORRECTIVE STEPS
1. Close switch.
2. Check electrical circuits and motor winding for shorts or
grounds. Investigate for possible overloading. Replace
fuse after fault is corrected.
3. Overloads are auto. reset. Check unit closely when unit
comes back on line.
4. Repair or replace.
5. Determine type and cause of shutdown and correct it.
before resetting safety switch.
6. None. Wait until unit calls for cooling.
7. Repair or replace coil.
8. Check motor for opens. short circuit or burn-out.
9. Check all wire junctions. Tighten all terminal screws.
1 Check setting of expansion valve.
2. Replace.
1. Clean.
2. Purge the
3. Remove excess.
4. Open valve.
1. Check condenser control operation.
2. Open valve.
3. Check for leaks. Repair and add charge.
4. See
5. See below for Corrective Steps for failure of compressor
to load up.
6. Reset controls.
1.
Reduce load or add
2. Check remote bulb. Regulate superheat.
3 See Corrective Steps below for failure of compressor
to load up.
1.
Check for leaks. Repair and add charge.
2. Clean chemically.
3. Replace cartridge(s).
4. Clean
5. Check and reset for proper superheat. Replace if necessary.
6. Check means for regulating condensing temperature.
7. See Corrective Steps for
8. Adjust gpm.
1. Replace.
2. Replace.
3. Replace.
4. Reset thermostat setting to fit application.
1. Replace.
2. Adjust gpm.
1.
Clean.
2.
Check
superheat. Check liquid line solenoid valve operation.
3. Repair or replace. Keep valve closed except when taking
readings.
4. Replace.
5. Replace.
6. Reverse
7. Replace compressor.
8. Add oil.
9. Check and tighten system.
10. Replace gasket.
11. Adjust thermal expansion valve.
1. Check for leaks and repair. Add refrigerant.
2. Replace compressor.
1. Check supply voltage for excessive line drop.
2. Replace compressor-motor.
3. Check all connections and tighten.
4. See Correctwe Steps for high discharge pressure.
5. Check supply voltage. Notify power company. Do not
Provide
6.
7. Repair or replace starter or time
1. Add facilities so that conditions are within allowable limits.
2. Open valve.
3. Replace gasket.
1.
Reset to 400F or above.
2. Adjust gpm.
3. See “Low
non-condensables.
below for
Corrective Steps for low suction pressure.
additional
strainers
crankcase heater. Reset expansion valve for higher
direction
of compressor rotation.
start until fault is corrected.
ventilation to reduce heat.
suction
pressure”.
equipment.
failure of
compressor to unload.
delay
mechanism.
PAGE 27
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