McQuay ALS 141C Installation Manual
Installation, Operation and Maintenance Manual
Air-Cooled Screw Compressor Chiller
ALS 141C through 218C
60 Hertz
IOMM A L S -4
Group: Chiller
Part Number: 330145709
Date: August 2001
Supersedes: IOMM ALS-3
Table Of Contents
Introduction ..............................3
General Description................................... 3
Nomenclature ............................................3
Inspection ..................................................3
Installation and Start-up ...........3
Handling.................................................... 4
Location..................................................... 5
Service Access...........................................5
Clearance Requirements............................6
Vibration Isolators .....................................7
Lifting and Mounting Weights...................8
Water Piping..............................................9
System Water Volume.............................. 10
Variable W ater Flow................................10
Evaporator Freeze Protection..................11
Flow Switch............................................. 11
Water Connections................................... 12
Refrigerant Charge................................... 12
Glycol Solutions...................................... 12
Remote Evaporator.................13
General....................................................13
Performance Derate Factors....................13
Refrigerant Piping....................................14
Startup Procedures...................................17
Dimensions, Remote Evaporator .............18
Water Flow and Pressure Drop19
Physical Data..........................21
Compressor Staging................22
Unit Layout and Principles of
Operation ................................43
Major Component Location.....................43
Control Center......................................... 43
Sequence of Operation ............................44
Start-up and Shutdown ...........47
Seasonal Start-up ..................................... 47
Temporary Shutdown...............................47
Start-up After T emporary Shutdown........ 48
Extended (Seasonal) Shutdown ...............48
Start-up After Extended (Seasonal)
Shutdown................................................. 49
System Maintenance...............50
General....................................................50
Compressor Maintenance........................ 50
Lubrication..............................................50
Electrical Terminals................................. 50
Condensers..............................................50
Refrigerant Sightglass .............................. 51
Lead-Lag .................................................51
Preventative Maintenance Schedule........ 52
Service ....................................53
Compressor Solenoids.............................53
Filter-Driers............................................. 53
Liquid Line Solenoid Valve..................... 55
Electronic Expansion Valve..................... 55
Electronic Expansion Valve Operation.... 56
Evaporator............................................... 57
Charging Refrigerant ............................... 57
Charging Oil............................................58
Dimensional Data ...................23
Wind Baffles and Hail Guards24
Electrical Data ........................26
Field Wiring.............................................26
Wire Sizing Ampacities...........................27
Field Wiring Diagram.............35
In-Warranty Return Material
Procedure ................................59
Standard Controls ...................60
Optional Controls....................................64
Controls, Settings and Functions ............. 65
Troubleshooting Chart............................. 66
Periodic Maintenance Log.......................67
Solid State Starters .................36
Our facility is ISO Certified
"McQuay" is a registered trademarks of McQuay International
"Information covers the McQuay International products at the time of publication and we reserve the right to make changes in design
2 IOMM ALS-4
Initial Issue January 1998
2001 McQuay International
and construction at anytime without notice"
Introduction
N
General Description
McQuay air-cooled water chillers are complete, self-contained automatic refrigerating units that
include the latest in engineering components arranged to provide a compact and efficient unit. Each
unit is completely assembled, factory wired, evacuated, charged, tested and comes complete and
ready for installation, except for remote evaporator models. Each unit consists of multiple air-cooled
condensers with integral subcooler sections, multiple accessible semi-hermetic single-screw
compressors, solid-state starters, multiple circuit shell-and-tube evaporator, and complete refrigerant
piping. Liquid line components included are manual liquid line shutoff valves, charging valves, filterdriers, liquid line solenoid valves, sightglass/moisture indicators, and electronic expansion valves.
Compressor suction and discharge shutoff valves are included. Other features include compressor
heaters, an evaporator heater for low ambient water freeze protection, automatic one time pumpdown
of refrigerant circuit upon circuit shutdown, and an advanced fully integrated microprocessor control
system.
Nomenclature
A L S - XXX C
Air-Cooled
Liquid Oil Injected
Rotary Screw Compressor
Inspection
When the equipment is received, all items should be carefully checked against the bill of lading to
ensure a complete shipment. All units should be carefully inspected for damage upon arrival. All
shipping damage must be reported to the carrier and a claim must be filed with the carrier. The unit’s
serial plate should be checked before unloading the unit to be sure that it agrees with the power
supply available. Physical damage to unit after acceptance is not the responsibility of McQuay
International.
Note: Unit shipping and operating weights are available in the Physical Data Tables.
Installation and Start-up
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.
Sharp edges and coil surfaces are a potential injury hazard. Avoid contact with them.
Start-up by McQuayService is included on all units sold for installation within the USA and Canada
and must be performed by them. Two week prior notification of start-up is required. The contractor
should obtain a copy of the Start-up Scheduled Request Form from the sales representative or from
the nearest office of McQuayService.
Design Vintage
ominal Tons
CAUTION
IOMM ALS-4 3
Handling
Care should be taken to avoid rough handling or shock due to impact or 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 and end frame (see Figure 1).
Never allow any part of the unit to fall during unloading or moving as this may result in serious
damage.
To lift the unit, 2½ “ (64 mm) diameter lifting holes are 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).
Figure 1, Suggested Pushing Method
Figure 2, Required Lifting Method
NOTES:
1. All 4 rigging points on a unit must be used. See Figure 5 through
a specific size unit.
2. Crosswise and lengthwise spreader bars m ust be used to avoid damage to unit. Li ft i ng cables from the unit
mounting holes up mus t be vertical.
3. The number of condenser sect i ons, and fans can vary from thi s diagram.
Figure 6 for location, and weight at lift i ng poi nts for
4 IOMM ALS-4
Location
Care should be taken in the location of the unit to provide proper airflow to the condenser. (See
Figure 3 for required clearances).
Due to the vertical condenser coil design of the ALS chillers, it is recommended that the unit be
oriented so that prevailing winds blow parallel to the unit length, thus minimizing the wind effect on
condensing pressure and performance. It is recommended that wind baffles be installed if the unit is
installed with no protection against prevailing winds.
Using less clearances than shown in Figure 3, will cause discharge air recirculation to the condenser
and could have a significant and detrimental effect on unit performance. See the current version of
McQuay Product Manual PM ALS for more detailed information on the subject of air recirculation.
Service A ccess
Each end of the unit must be accessible after installation for periodic service work. Compressors,
filter-driers, and manual liquid line shutoff valves are accessible on each side of the unit adjacent to
the control box. High pressure and low pressure transducers are mounted on the compressor. The
cooler barrel heater thermostat is located on the cooler. Compressor microprocessor and most other
operational and equipment protection controls are located in the unit control box. The solid-state
starters with their internal electrical protection features are mounted on the base side rails adjacent to
the compressor they serve.
On all ALS units the condenser fans and motors can be removed from the top o f the unit. The
complete fan/motor assembly can be removed for service. The fan blade and fan motor rain shield
must be removed for access to wiring terminals at the top of the motor.
WARNING
Disconnect all power to the unit while servicing condenser fan motors.
Failure to do so may cause bodily injury or death.
Do not block access to the sides or ends of the unit with piping or conduit. These areas must be open
for service access. Do not block any access to the control panel with a field mounted disconnect
switch.
IOMM ALS-4 5
Clearance Requirements
Figure 3, Clearance Requirements, ALS 141-218
Notes:
1. Minimum side clearance between two units is 12 feet.
2. Unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unit
unless extra clearance is provided per note 4.
3. Minimum clearance on each side is 8 feet when installed in a pit no deeper than the unit height.
4. Minimum side clearance to a side wall or b uilding taller than the unit height is 8 feet provided no
solid wall above 6 feet is closer than 12 feet to the opposite side of the unit.
5. The evaporator can be removed from the side of the unit.
6. Do not mount electrical conduits, etc, above the side rail on either side if the unit.
7. There must be no obstruction of the fan discharge.
8. It is recommended that field supplied disconnect switches not be mounted on the unit.
6 IOMM ALS-4
Vibration Isolators
Vibration isolators are recommended for all roof mounted installations or wherever vibration
transmission is a consideration. The following section "Lifting and Mounting Weights" co ntains the
location of unit lifting holes and the load at each location. Mounting holes are also dimensioned and
the bearing weight at each hole given.
The unit should be initially installed on shims or blocks at the illustrated "free height" of the isolator.
Six inches for the McQuay isolators shown. When all piping, wiring, fl ushing, charging, etc is
complete, the springs should be adjusted upward to load them and free the blocks which are then
removed.
Installation of spring isolators requires flexible pipe connections and at least three fett of conduit flex
tie-ins. Piping and conduit should be supported independently from the unit.
Figure 4, Spring Flex Isolators
Table 1, Spring Vibration Isolators, Part Numbers
Mounting Location (See Footprint Drawings Figure 5 or Figure 6
Model R1 R2 R3 R4 R5 R6
ALS 141-ALS 186 Isolator kit part number 350014880
Max Load 2200 2200 2600 2600 1800 1800
Spring P/N 022611901 022611901 022612000 02261200 022611800 022611800
Color Gray Gray White White Green Green
Housing P/N 022610300 022610300 022610300 022610300 022610300 022610300
ALS 190-ALS 218 Isolator kit part number 350014881
Max Load 2600 2600 3000 3000 2200 2200
Spring P/N 022612000 022612000 330202101 330202101 022611901 022611901
Color White White Gold Gold Gray Gray
Housing P/N 022610300 022610300 022610300 022610300 022610300 022610300
Notes:
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
2. The spring is fully compressed at approximately 3900 lb. (1769 kg).
IOMM ALS-4 7
Lifting and Mounting Weights
Figure 5, ALS 141C – ALS 186C Lifting and Mounting Locations
NOTES:
1. 2 ½ in. (63.5 mm) lifting holes at location "L" on side of base rail.
2. 1 in. (25.4 mm) mounting holes at location "R" on bottom of base rail.
L2
R2
36 (914)
BOX
CONTROL
46 (1168)
Lifting Weight for Each Point
ALS
Model
141 2585 (1171) 2125 (963) 1835 (831) 1785 (809) 1230 (557) 9700 (4394) 9420 (4267) 1370 (620)
150 2570 (1164) 2205 (999) 1830 (829) 1805 (818) 1305 (591) 9880 (4476) 9550 (4326) 1370 (620)
171 2570 (1164) 2210 (1001) 1830 (829) 1810 (820) 1305 (591) 9890 (4472) 9560 (4331) 1370 (620)
186 2575 (1166) 2210 (1001) 1830 (829) 1810 (820) 1310 (593) 9900 (4485) 9570 (4335) 1370 (620)
lb (kg)
L1 & L2 L3 & L4 R1 & R2 R3 & R4 R5 & R6
102 (2591)
R1
L1
R4
192 (4877)
161 (4089)
R3
Mounting Loads for Each Point
lb. (kg)
L4
R6
83.4
(2118)
R5
L3
Operating Wt
lb. (kg)
2 (51)
Typical Spacing
for Isolator
Mounting (6)
Shipping Wt.
lb. (kg)
Copper Fin
Figure 6, ALS 190C – ALS 218C Lifting and Mounting Locations
Add
L2
R2
36 (914)
BOX
CONTROL
46 (1168)
Lifting Weight for Each Point
ALS
Model
190 2915 (1320) 2230 (1010) 2010 (910) 2135 (967) 1165 (527) 10620 (4811) 10290 (4661) 1610 (730)
200 2920 (1323) 2230 (1010) 2015 (913) 2135 (967) 1165 (527) 10630 (4815) 10300 (4666) 1610 (730)
206 2940 (1332) 2310 (1046) 2000 (906) 2240 (1015) 1240 (562) 10960 (4965) 10500 (4756) 1610 (730)
218 2960 (1341) 2405 (1089) 1985 (899) 2425 (1098) 1365 (618) 11550 (5232) 10730 (4861) 1610 (730)
L1 & L2 L3 & L4 R1 & R2 R3 & R4 R5 & R6
123 (3124)
195 (4953)
R1
L1
lb (kg)
R4
224 (5690)
R3
Mounting Loads for Each Point
lb. (kg)
L4
R6
83.4
(2118)
R5
L3
Operating Wt
lb. (kg)
2 (51)
Typical Spacing
for Isolator
Mounting (6)
Shipping Wt.
lb. (kg)
Copper Fin
Add
8 IOMM ALS-4
Water Piping
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:
1. Vibration eliminators to red uce vibratio n and noise transmission to the building.
2. Shutoff valves to isolate the unit from the piping system during unit servicing.
3. Manual or automatic air vent valves at the high points of the system. Drains at the low parts in
the system. The evaporator should not be the highest point in the piping system.
4. Some means of maintaining adequate system water pressure (e.g., expansion tank or regulating
valve).
5. Water 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.
The strainer 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 help maintain high system performance levels.
WARNING
7. A strainer must also be placed in the supply water line just prior to the inlet of the evaporator.
This will aid in preventing foreign material from entering the evaporator and causing damage or
decreasing its performance. Care must also be exercised if welding pipe to the evaporator
connections to prevent any weld slag from entering the vessel.
8. The shell-and-tube evaporator has a thermostat and heating cable to prevent freeze-up down to 20°F (-28.8°C). It is suggested that the heating cable be wired to a separat e 110V supply circuit.
As shipped from the factory, it is factory wired to the control circuit. Any water piping to the unit
must also be protected to prevent freezing.
9. If the unit is used as a replacement chiller on a previously existing piping system, the system
should be thoroughly flushed prior to unit installation and then regular c hille d water analysis and
chemical water treatment is recommended immediately at equipment start-up.
10. The total water quantity in the system should be sufficient to prevent frequent "on-off" cycling.
For air-conditioning systems, system gallons equal to 7 time the flow rate is recommended.
11. In the event glycol is added to the water system, as an afterthought for freeze protection,
recognize that the refrigerant suction pressure will be lower, cooling performance less, and water
side pressure drop greater. If the percentage of glycol is large, or if propylene is employed in lieu
of ethylene glycol, the added pressure drop and loss of performance could be substantial.
12. For operations requiring the ice mode feature, logic in MicroTech will adjust the freezestat to a
pressure equi valent to 13.5°F (7.5°C) below the leaving evaporator water temperature. However,
if a different freezestat pressure value is desired, the freezestat can be manually changed through
MicroTech. Refer to the current OM ALSMICRO for additional information.
CAUTION
If a separate disconnect is used for the 110V supply to the cooler heating cable, it should be clearly
marked so that it is not accidentally shut off during cold seasons.
A preliminary leak check should be made prior to insulating the piping and filling the system,.
Piping insulation should include a vapor barrier to prevent moisture condensation and possible
damage to the building structure. It is important to have the vapor barrier o n the outside of the
insulation to prevent condensation within the insulation on the cold surface of the pipe.
IOMM ALS-4 9
System Water Volume
It is important to have adequate water volume in the system to provide an opportunity for the chiller
to sense a load change, adjust to the change and stabilize. As the expected load change becomes more
rapid, a greater water volume is needed. The system water volume is the total amount of water in the
evaporator, air handling products and associated piping. If the water volume is too low, operational
problems can occur including rapid compressor cycling, rapid loading and unloading of compressors,
erratic refrigerant flow in the chiller, improper motor cooling, shortened equipment life and other
undesirable occurrences.
For normal comfort cooling applications where the cooling load changes relatively slowly, we
recommend a minimum system volume of five minutes times the flow rate (gpm). For example, if the
design chiller flow rate is 400 gpm, we recommend a minimum system volume of 2000 gallons (400
gpm x 5 minutes).
For process applications where the cooling load can change rapidly, additional system water volume
is needed. A process example would be a quenching tank. The load would be very stable until the hot
material is immersed in the water tank. Then, the load would increase drastically. For this type of
application, system volume may need to be increased drastically.
Since there are many other factors that can influence performance, systems may successfully operate
below these suggestions. However, as the water volume decreases below these suggestions, the
possibility of problems increases.
Variable Water Flow
Variabl e water flow involves changing the water flow through the evaporator as the load changes.
McQuay chillers are designed for this duty provided that the rate of change in water flow is slow and
the minimum and maximum flow rates for the vessel are not exceeded.
The recommended change in water flow is listed in the table below. As the number of stages of
control increase, the slower the permissible rate of change in flow rate becomes. The ALS control
logic has timers that limit the rate of unloading or loading allowed. Slow changes allow the chiller the
opportunity to sense a change, react to the change and stabilize preventing operational problems.
ALS Size
141 to 218 2 8 10.0
For example, assume that an ALS with two compressors has a design flow of 500 gpm and the
minimum vessel flow rate of 300 gpm. The allowable amount of flow change is 200 gpm. An ALS
with two compressors has an allowable change rate of 10% of change per minute. Therefore, the
maximum rate of change recommended would be 20 gpm/minute (200 X .10).
The water flow through t he vessel must remain between the minimum and maximum values listed on
Figure 13. If flow drops below the minimum allowable, large reductions in heat transfer can occur. If
the flow exceeds the maximum rate, excessive pressure drop and tube erosion can occur.
Number of
Compressors
Unloading
Steps
Maximum allowable % per
minute of flow change
10 IOMM ALS-4
Evaporator Freeze Protection
All evaporators come equipped with thermostatically controlled resistive element heater. When
power is applied to terminals 13 and 16, the heat element will provide freeze protection down to 20°F (-28.8°C). However, this should not be the only method of freeze protection. Unless the
evaporator is flushed and drained as is described below in note 4, two or more of the remaining three
recommendations must be followed as part of the system design:
1. Continuous circul ation of water through the piping and the heat exchanger.
2. The inclusion of glycol solution in the chilled water circuit.
3. The addition of insulation and heat to the exposed piping.
4. Draining and flushing the chiller vessel with glycol during subfreezing weather. NOTE: The
heater element must be disconnected and made inoperative any time there is no fluid in the
evaporator. Failure to do so can cause the element to create excessive heat and to burn out.
It is the responsibility of the installing contractor and/or on-site maintenance personnel to insure that
this additional protection is provided. Routine checks should be made to insure adequate freeze
protection is maintained.
Failure to do so may result in damage to unit components. Freeze damage is not considered a
warranty failure.
Freeze protection should also be extended to any water piping exposed to freezing temperatures.
Figure 7, Typical Field Water Piping
Vent
Outlet
Drain
Vibration
Eliminator
Valved
pressure
gauge
Water
strainer
Vibration
Eliminator
Gate valve
Flow
Balancing
Switch
Protect all field piping
against freezing
valve
Gate valve
Flow Switch
A water flow switch must be mounted in the leaving water line to insure that there will be adequate
water flow 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 McQuay under ordering number 017503300. It is a "paddle" type
switch and adaptable to any pipe size from 1" (25mm) to 8" (203mm) nominal.
Certain minimum flow rates are required to close the switch and are listed in Table 2. Installation
should be as shown in Figure 8.
Electrical connections in the unit control center should be made at terminals 62 and 63. The normally
open contacts of the flow switch should be wired between these two terminals. Flow switch contact
quality must be suitable for 24 VAC, low current (16ma). Flow switch wire must be in separate
conduit from any high voltage conductors (115 VAC and higher).
IOMM ALS-4 11
Figure 8, Flow Switch
Flow direction marked
on switch
1" (25mm) NPT flow
switch connection
Tee
Table 2, Switch Minimum Flow Rates
NOMINAL PIPE SIZE
INCHES (MM)
5 (127) 58.7 (3.7)
6 (152) 79.2 (5.0)
8 (203) 140 (8.8)
Note: Water pressure differential switches are not recommended
for outdoor applications.
MINIMUM REQUIRED FLOW TO
ACTIVATE SWITCH - GPM (LPS)
1 1/4" (32mm) pipe
dia. min. after switch
1 1/4" (32mm) pipe
dia. min. before switch
Water Connections
Water piping to the cooler can b e brought up through the bottom of the uni t or through the sid e
between the vertical supports. The dimensional drawings in Figure 14 give the necessary dimensions
and locations for all piping connections. Evaporator piping connections face toward the left side of
the unit when looking at the control panel.
Refrigerant Charge
All units are designed for use with HCFC-22 (and are compatible with some HCFC alternatives) and
are shipped with a full operating charge. The operating charge for each unit is shown in the Physical
Data Tables. Units ordered with a remote evaporator are shipped with a unit operating charge of
refrigerant pumped down in the unit condensers. The McQuay authorized startup technician will top
off the system charge at startup.
Glycol Solutions
When using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and pressure
drop through the cooler may be calculated using t he following formulas and t ables.
Note: The procedure below does not specify the type of glycol. Use the derate factors found in Table
3 for corrections when using propylene glycol and those in Table 4 for ethylene glycol.
1. Capacity - Cooling capacity is reduced from that with plain water. To find the reduced value,
multiply the chiller’s water system tonnage by the capacity correction factor to find the chiller’s
capacity when using glycol.
2. Flow - To determine flow (or delta-T) knowing delta-T (or flow) and capacity:
()( )( )
GPM−=
Pressure drop - To determine pressure dr op through the cooler, when using glycol, enter the
3.
24
factorflowtons
TDelta
water pressure drop curve at the water flow rate. Multiply the water pressure drop found there by
the "PD" factor to obtain corrected glycol pressure drop.
To determine glycol system kW, multiply the water system kW by the factor designated "Power".
4.
Test coolant with a clean, accurate glycol solution hydrometer (similar to that found in service
stations) to determine the freezing point. Obtain percent glycol from the freezing point table below.
On glycol applications the supplier normally recommends that a minimum of 25% solution by weight
be used for protection against corrosion.
12 IOMM ALS-4
CAUTION
Do not use automotive grade antifreeze. Industrial grade glycols must be used. Automotive antifreeze
contains inhibitors that will cause plating on the copper tubes within the chiller evaporator. The type and
handling of glycol used must be consistent with local codes.
Table 3, Propylene Glycol
FREEZE
%
POINT.
P.G.
o
FoC
10 26 -3 0.987 0.992 1.010 1.068
20 19 -7 0.975 0.985 1.028 1.147
30 9 -13 0.962 0.978 1.050 1.248
40 -5 -21 0.946 0.971 1.078 1.366
50 -27 -33 0.965 0.965 1.116 1.481
CAP POWER FLOW PD
Remote Evaporator
General
The multiple compressor ALS air-cooled chillers are available with the evaporator shipped loose for
remote mounting. This allows the main unit to be installed outdoors to save interior room and
eliminates the need for anti-freeze solutions and heat tracing of chilled water lines since the chilled
water system is indoors. There are some general guidelines to review before proceeding:
R-22 only.
1.
2.
Maximum line length of 50 ft (15 m) and Total Equivalent Length (TEL) of 120 ft (37 m).
3.
Evaporator not more than 6 ft (1.8 m) above the compressor or 16 ft (5 m) below compressor.
Table 4, Ethylene Glycol
FREEZE
%
E.G.
POINT.
oFo
10 26 -3 0.991 0.996 1.013 1.070
20 18 -8 0.982 0.992 1.040 1.129
30 7 -14 0.972 0.986 1.074 1.181
40 -7 -22 0.961 0.976 1.121 1.263
50 -28 -33 0.946 0.966 1.178 1.308
CAP POWER FLOW PD
C
4.
No underground piping.
5.
No hot gas bypass.
6.
Units with remote evaporator are not included in the ARI Certification Program.
The remote evaporator is shipped separately, ready for quick and easy installation at the job site. All
refrigerant accessories such as liquid-vapor line shut-off valves, replaceable core filter-driers, liquid
line solenoid valves, electronic expansion valves, and sightglasses are already included on the ALS
condensing unit. The evaporator is equipped with entering and leaving chilled water temperature
sensor wells. The sensors are pre-wired to the ALS unit with 75 feet long sensor leads and must be
field connected to the evaporator thermowells. Suction pressure transducers and temperature sensors
must also be relocated to the evaporator. ALS units are factory charged with a full unit charge
pumped down into the condensers. Field piping must be leak tested, evacuated and charged during
installation. Do not exceed 150 psig test pressure unless the unit is blanked off from the piping.
Performance Derate Factors
All performance tables and adjustment factors found in the current version of the Air-Cooled Screw
Chiller catalog (PM ALS-x) are applicable for remote evaporator installations. However, a
performance derate must be applied to the R-22 performance data due to additional pressure drops in
the suction and liquid lines which cause a loss of compressor performance. These derates are based
on a suction line pressure drop equivalent of approximately 2°F (1°C) change in saturation
temperature.
For R-22 applications:
Capacity = Tons (kW) x 0.97 Power = Compressor kW x 0.99
IOMM ALS-4 13
Refrigerant Piping
General
Careful design of the refrigerant piping is necessary for efficient system operation. The refrigerant
piping should be designed for a low refrigerant pressure drop to obtain maximum capacity and
efficiency while maintaining adequate velocity. Lines should slope in the direction of flow to assure
good oil return to the compressors. Cost considerations favor keeping line sizes as small as possible
while not exceeding acceptable pressure drops in order to maintain unit performance.
NOTE
All refrigerant piping must be reviewed and approved by McQuay Application
Engineers prior to order entry and will be verified by McQuay startup technicians.
Equivalent Line Lengths
Recommended refrigerant line sizes are based on equivalent line lengths of straight pipe, that is, a
combination of straight pipe , fittings and valves. The pressure drop through valves and fittings is
determined by establishing the equivalent straight length of pipe of the same size with the same
friction lo ss. The "Total Equivalent Length" is the sum of the "Lineal Line Length" and the
appropriate "Valve and Fitting Losses in Equivalent Feet of Pipe for Field Supplied Piping" given in
Table 5
Table 5, Fitting Equivalent Feet of Pipe
Line Size (in.) Angle Valve Globe Valve 90° Std. Radius Elbow 90° Long Radius Elbow
1 1/8 12 29 2.6 1.7
1 3/8 15 38 3.3 2.3
1 5/8 18 43 4.0 2.6
2 1/8 24 55 5.0 3.3
2 5/8 29 69 6.0 4.1
3 1/8 35 84 7.5 5.0
Location and Arrangement
Refrigerant lines should be as short and direct as possible to minimize tubing and fittings. Long
radius elbows must be used (except for traps) to minimize the pressure drops. Traps should be as
short as possible to minimize oil accumulation. Refrigerant piping should be arranged so that normal
inspection of the equipment is not hindered. Adequate clearance should be provided between
refrigerant piping and adjacent walls for insulation. Piping should be run so that it does not interfere
with compressor service access, passages or obstruct headroom, windows and doors. Suction line
hangers must be sized and located to support the weight of the piping in accordance with good piping
practice.
Horizontal portions of the suction lines must be downward sloping toward the compressors. Slope all
piping in the direction of flow. Vertical portions of the suction lines must be sized for oil return at
minimum compressor load.
Note: Double section risers must not be utilized on any circuit. Traps must be provided as shown on
Figure 9 and Figure 10.
Suction Line Sizing
Pressure drop in the suction line reduces system capacity and efficiency because it forces the
compressor to operate at lower suction pressure. The suction line should be sized for a pressure drop
approximately equivalent of 2°F (1°C) change in saturation temperature. For suction line sizing see
Table 7 and Table 8. For applications with the evaporator below the ALS unit, the vertical section of
the suction lines must be sized to return oil to the compressors at the minimum compressor capacity
step.
14 IOMM ALS-4
Example of Suction Line Size Calculation
ALS150C condensing unit with refrigerant R-22
Evaporator located 5 feet below the ALS compressor
Lineal length of horizontal suction line is 25 feet
Suction line requires 7 long radius (90°) elbows; 3 in the horizontal, 4 in the riser
From Table 6, the nominal circuit capacities for circuit 1 and 2 are 65 and 80 tons respectively
Total lineal suction line length = 30 feet each circuit (25 feet horizontal plus 5 feet vertical riser).
For the first try, assume that the
total equivalent suction line length is twice the lineal suction line
length.
Therefore the estimated
From Table 7 and Table 8, For nominal circuit capacities of 65 & 80 tons and
total equivalent suction line length = 60 feet
total equivalent line
length of 60 ft, the suction line size = 2 5/8" for horizontal lines and 2 1/8" for vertical lines.
From Table 5, Fitting loss for 2 5/8" lo ng radius (90°) elbow = 4.1 ft, and 3.3 ft for the 2 1/8 elbows.
Therefore fitting loss in equivalent feet of pipe for (3) 2 5/8" long radius (90°) elbow = 12.3 ft,
and 13.2 ft for (4) 2 1/8" elbows.
Therefore the actual
equivalent suction line length = 30 + 12.3 + 13.2 = 55.5 feet
From and Table 8, For nominal circuit capacities of 65 & 80 tons and equivalent line length of 55.5 ft
the suction line size is correct.
Table 6, ALS 141C-420C Nominal Circuit Capacities
ALS Model
141 65 (229) 65 (229)
150 65 (229) 80 (262)
171 80 (262) 80 (262)
186 80 (262) 95 (334)
190 80 (262) 95 (334)
200 95 (334) 95 (334)
206 95 (334) 95 (334)
218 95 (334) 95 (334)
Circuit 1 Circuit 2
Tons (kW) Tons (kW)
Table 7, Vertical Upflow Suction Line Sizes
Nominal Circuit
Capacity
Tons (kW)
65 (229)
80 (262)
95 (334)
Equivalent Line Length Ft (m) Suction Line Size (in.)
Vertical Upflow Suction Lines
40 (12) 2 1/8
75 (23) 2 1/8
40 (12) 2 1/8
75 (23) 2 1/8
40 (12) 2 5/8
75 (23) 2 5/8
Table 8, Horizontal and Vertical Downflow Suction Line Sizes
Capacity
Tons (kW)
65 (229) 75 (23) 2 5/8
80 (262) 75 (23) 2 5/8
95 (334) 75 (23) 3 1/8
IOMM ALS-4 15
Vertical Downflow and Horizontal Suction LinesNominal Circuit
Equivalent Line Length Ft (m) Suction Line Size, in.
40 (12) 2 5/8
115 (35) 2 5/8
40 (12) 2 5/8
115 (35) 3 1/8
40 (12) 2 5/8
115 (35) 3 1/8
Liquid-Vapor Lines
r
The liquid-vapor line from the ALS condensing unit to the evaporator liquid connection is not a
conventional liquid line since it carries both liquid and vapor. The compressors on the ALS units
utilize a liquid cooled motor and an economizer. Therefore the expansion valve which feeds the full
flow of liquid refrigerant into the compressor for motor cooling is mounted in the liquid line between
the condenser sub-cooling coil and the compressor inlet, not at the evaporator inlet. The liquid-vapor
line to the evaporator is a low-pressure line downstream of the expansion valve and the size is slightly
larger than a normal liquid line. For liquid line sizing see Table 9 and Table 10.
Table 9, Vertical Upflow Liquid-Vapor Line Sizes
Nominal Circuit
Capacity
Tons (kW)
65 (229)
80 (262)
95 (334)
Equivalent Line Length
Table 10, Horizontal and Vertical Downflow Liquid-V apor Line Sizes
Capacity
Tons (kW)
65 (229) 75 (23) 1 3/8
80 (262) 75 (23) 1 5/8
95 (334) 75 (23) 1 5/8
Equivalent Line Length
Vertical Upflow Liquid-Vapor Lines
Ft (m)
40 (12) 1 3/8
75 (23) 1 3/8
40 (12) 1 3/8
75 (23) 1 3/8
40 (12) 1 5/8
75 (23) 1 5/8
Vertical Downflow and Horizontal Liquid-Vapor LinesNominal Circuit
Ft (m)
40 (12) 1 3/8
115 (35) 1 3/8
40 (12) 1 3/8
115 (35) 1 5/8
40 (12) 1 5/8
115 (35) 1 5/8
Liquid-Vapor Line Size
o.d (in.)
Liquid-Vapor Line Size
o.d (in.)
Figure 9, Evaporator Above ALS Unit
Evaporato
Trap
ALS Unit
Suction Line
Figure 10, Evaporator Below ALS Unit
ALS Unit
Suction Line
Evaporator
Trap
NOTE: Keep the trap width at a minimum to avoid trapping excessive oil.
16 IOMM ALS-4
Insulation
All piping joints and fittings must be thoroughly leak tested before insulation is applie d. Suction lines
must be insulated and should not be installed underground. Suction line insulation must be selected to
prevent condensation under local ambient conditions with the lines at 40°F to 50°F (4.4°C to 10°C)
operating temperatures. The liquid-vapor lines will operate at 40°F to 60°F (4.4°C to 15.6°C) and
must also be insulated to prevent sweating and heat gain.
Startup Procedures
NOTE: McQuayService or a factory authorized McQuay service agent must do initial start-up and
commissioning.
Filter Driers
Following an initial 24 hour operation the pressure drop across the replaceable core filter-drier should
be checked. If this pressure drop exceeds the values given in Table 11 at the various load conditions
the filter drier cores must be replaced. Also if the moisture indicating sight glass shows a wet system
condition after 24 hours of operation the filter cores must be changed. This should remove any
contaminants introduced during field piping. The filter drier cores must also be changed anytime the
system is opened for servicing.
Table 11, Filter Drier Pressure Drop
Percent Circuit
Loading (%)
100 7 (48.3)
75 5 (34.5)
50 3 (20.7)
25 3 (20.7)
Maximum Recommended Pressure Drop Across Filter Drier
psig (kPa)
Refrigerant and Oil Charge
The relative position of the ALS unit and the evaporator and the distance between them plays a
critical role in determining suction and liquid line sizes and the field refrigerant and oil charges. ALS
units with the remote evaporator option are shipped with a unit operating charge of refrigerant and oil.
It will be necessary to evacuate the evaporator and field installed line and top off the charge See
Table 12 for refrigerant charge for suction and liquid-vapor lines. McQuay Service will supply and
add additional oil as required. The correct oil is Planetelf ACD68AW, McQuay Part No.
735030439 (5 gal.), 735030438 (1 gal.).
Charging Procedure
The calculated refrigerant charge must be added through the factory supplied charging valve locat ed
on the liquid-vapor line coming out of the compressor. Sufficient charge must be added to clear the
liquid line sight glass located at the outlet of the condenser. Add an extra 10 lb. of refrigerant after
the sight glass is clear.
Table 12, Refrigerant Charge for Suction and Liquid-Vapor Lines
Lineal Tubing
Length
ft (m)
10 (3) 2 5/8 0.51 (0.23) 1 5/8 5.0 (2.3)
20 (6) 2 5/8 1.02 (0.46) 1 5/8 10.0 (4.5)
30 (9) 2 5/8 1.53 (0.69) 1 5/8 15.0 (6.8)
40 (12) 2 5/8 2.04 (0.92) 1 5/8 20.0 (9.0)
Suction Line Refrigerant Charge
lb (kg)
Line (in.) R-22 Line (in.) R-22
2 1/8 0.33 (0.15) 1 3/8 3.6 (1.6)
3 1/8 0.71 (0.32)
2 1/8 0.66 (0.30) 1 3/8 7.2 (3.3)
3 1/8 1.42 (0.64)
2 1/8 0.99 (0.45) 1 3/8 10.8 (4.9)
3 1/8 2.13 (0.96)
2 1/8 1.32 (0.60) 1 3/8 14.4 (6.5)
3 1/8 2.84 (1.29)
Notes: See next page
Liquid-Vapor Line Refrigerant Charge
lb (kg)
IOMM ALS-4 17
1. The only approved oil is that identified on the label attached to the compressors. All POE oils
are hygroscopic and care should be exercised in handling the oil to avoid absorption and
retention of moisture.
2.
Do not leave the oil container open for more than a minute while charging oil. Do not use oil that
has not been properly sealed and stored.
3.
Charge must never be ad ded through the compressor suction line
Dimensions
Use the ALS dimension drawings Figure 14 for the ALS with remote evaporator. The refrigerant
connections are located approximately where the refrigerant connections to the unit mounted
evaporator are on a packaged chiller. The remote evaporator dimensions are Figure 11 Figure 12.
Dimensions, Remote Evaporator
Figure 11, Evaporator for ALS 141 - ALS 200
ALS
Model
141 CDE350332801 34 (128) 1.4 (40. 0) 934 (424) 635 (288) 34 (15.4) 34 (15.4)
150-200 CDE350332901 40 (150) 1.8 (52.4) 1127 (512) 758 (343) 45 (20.4) 45 (20.4)
ALS
Model
141 94.6 (2403) 17.8 (452) 11.0 (279) 10.2 (259) 12.8 (325) 6.4 (163) 85.2 (2164) 5 (152)
150-200 95.5 (2426) 18.4 (467) 12.0 (305) 10.2 (259) 14.0 (356) 6. 8 (173) 84.0 (2134) 8 (203)
18 IOMM ALS-4
Evaporator
Model
Overall Dimensions in. (mm)
Length "K" Height "A" "B" "C" "D" "H" "J"
Water
Volume
gal. (l)
Refrigerant
Volume
cu. ft. (L)
Unit Weights lb. (kg) R-22 Operating Charge lb. (kg)
Operating Shipping Circuit 1 Circuit 2
Conn.
"G"
Figure 12, Evaporator for ALS 206 - ALS 218
ALS
Model
206 CDE350281651 55 (208) 2.4 (67.9) 1464 (665) 943 (428) 57 (25.8) 57 (25.8)
218 CDE350282101 98 (373) 2.8 (79.2) 2028 (921) 1121 (509) 68 (30.9) 68 (30.9)
Model
206 21.3 (542) 12.1 (307) 16.0 (406) 6.9 (176) 84.5 (2149) 96.7 (2459)
218 23.6 (601) 12.4 (315) 20.0 (508) 9.2 (235) 86.6 (2202) 99.7 (2533)
Evaporator
Model
ACD H JK
Water Volume
gal. (l)
Refrig Volume
cu. ft. (l)
Water Flow and Pressure Drop
The chilled water flow through the evapor ator should be adjuste d to meet specified conditions. The
flow rates must fall between the minimum and maximum values shown in. Flow rates below the
minimum values shown will result in laminar flow that will reduce efficiency, cause erratic operation
of the electronic expansion valve and could cause low temperature cutouts. On the other hand flow
rates exceeding the maximum values shown can cause erosion on the evaporator water connections
and tubes.
Measure the chilled water pressure drop through the evaporator at field installed pressure taps. It is
important not to include valve or strainer pressure drop in these readings.
Weights lb. (kg) R-22 Opn Charge lb. (kg)
Operating Shipping Circuit 1 Circuit 2
Dimensional DataALS
IOMM ALS-4 19
Figure 13, Evaporator Pressure Drops
ALS 206
ALS 141
ALS 150-200
ALS 218
Table 13, Minimum/Nominal/Maximum Flow Rates
ALS
Unit
Size
141
150
171
186
190
200
206
218
Minimum
Flow gpm
Pressure
Drop ft.
Nominal
Flow gpm
Pressure
Drop ft.
187 4.0 298.8 9.5 498 24.2
209 4.2 335.3 10.5 559 28.5
234 5.2 373.9 13.0 623 35.3
255 6.1 408.0 15.4 680 41.9
260 6.4 415.4 16.0 692 43.4
276 7.2 442.1 18.0 737 49.0
285 7.5 456.7 18.7 761 50.4
307 5.0 490.6 13.1 818 36.8
Maximum
Flow gpm
Pressure
Drop ft.
20 IOMM ALS-4
Physical Data
Table 14, Physical Data, ALS 141C – ALS 186C
DATA 141C 150C 171C 186C
BASIC DATA
Unit Cap. @ ARI Conditions, tons (kW) 124.5 (436) 139.7 (489) 155.8 (545) 170 (595)
Unit Operating Charge R-22, lbs (kg) 140 (63.5) 140 (63.5) 140 (63.5) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 160 (72.6)
Cabinet Dimensions
L x W x H, in. (mm)
Unit Operating Weight, lbs. (kg) 9700 (4395) 9880 (4475) 9890 (4480) 9900 (4485)
Unit Shipping Weight, lbs (kg) 9420 (4270) 9550 (4325) 9560 (4330) 9570 (4335)
COMPRESSORS, SCREW, SEMI-HERMETIC
Nominal Capacity, tons (kW) 65 (230) 65 (230) 65 (230) 80 (280) 80 (280) 80 (280) 80 (280) 95 (335)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TY PE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7)
Finned Height x Finned Length
ft. (mm)
Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE
No. of Fans -- Fan Diameter, in. (mm) 10 - 28 (711) 10 - 28 (711) 12 - 28 (711) 12 - 28 (711)
No. of Motors -- hp (kW) 10 - 1.5 (1.1) 10 - 1.5 (1.1) 12 - 1.5 (1.1) 12 - 1.5 (1.1)
Fan & Motor RPM, 60Hz 1140 1140 1140 1140
60 Hz Fan Tip Speed, fpm 8357 8357 8357 8357
60 Hz Total Unit Airflow, cfm 90200 90200 108240 108240
EVAPORATOR, DIRECT EXPANSION
Shell Dia.- Length
in.(mm) - in. (mm)
Evaporator R-22 Charge lbs (kg) 34 (15.4) 34 (15.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4)
Water Volume, gallons (liters) 34 (129) 40 (151) 40 (151) 40 (151)
Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) 152 (1048)
Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068) 300 (2068)
Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2
228.7 x 83.4 x 92.5
(5809 x 2118 x 2350)
80 x 208
(2032 x 5283)
12.75 – 94.6
(324 - 2403)
80 x 208
(2032 x 5283)
228.7 x 83.4 x 92.5
(5809 x 2118 x 2350)
80 x 208
(2032 x 5283)
ALS MODEL NUMBER
80 x 208
(2032 x 5283)
14.0 – 95.5
(356 - 2425)
228.7 x 83.4 x 92.5
(5809 x 2118 x 2350)
80 x 208
(2032 x 5283)
(2032 x 5283)
14.0 – 95.5
(356 - 2425)
80 x 208
228.7 x 83.4 x 92.5
(5809 x 2118 x 2350)
80 x 208
(2032 x 5283)
14.0 – 95.5
(356 - 2425)
80 x 208
(2032 x 5283)
Table 15, Physical Data, ALS 190C – ALS 218C
DATA 190C 200C 206C 218C
BASIC DATA
Unit Cap. @ ARI Conditions, tons (kW) 173.1 (606) 184.2 (645) 190.3 (666) 204.4 (715)
Unit Operating Charge R-22, lbs (kg) 170 (77.0) 180 (81.5) 180 (81.5) 180 (81.5) 185 (83.8) 185 (83.8) 210 (95.1) 210 (95.1)
Cabinet Dimensions,
L x W x H, in. (mm)
Unit Operating Weight, lbs. (kg) 10620 (4810) 10630 (4815) 10960 (4965) 11550 (5230)
Unit Shipping Weight, lbs (kg) 10290 (4660) 10300 (4665) 10500 (4755) 10730 (4860)
COMPRESSORS, SCREW, SEMI-HERMETIC
Nominal Capacity, tons (kW) 80 (280) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335)
CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TY PE WITH INTEGRAL SUBCOOLER
Coil Face Area, ft2. (m2) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5)
Finned Height x Finned Length
ft. (mm)
Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3
CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE
No. of Fans -- Fan Diameter, in. (mm) 14 - 28 (711) 14 - 28 (711) 14 - 28 (711) 14 - 28 (711)
No. of Motors -- hp (kW) 14 - 1.5 (1.1) 14 - 1.5 (1.1) 14 - 1.5 (1.1) 14 - 2.0 (1.5)
Fan & Motor RPM, 60Hz 1140 1140 1140 1140
60 Hz Fan Tip Speed, fpm 8357 8357 8357 8357
60 Hz Total Unit Airflow, cfm 126280 126280 126280 138908
EVAPORATOR, DIRECT EXPANSION
Shell Dia. -- Length
in.(mm) - in. (mm)
Evaporator R-22 Charge lbs (kg) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 57 (25.8) 57 (25.8) 68 (30.8) 68 (30.8)
Water Volume, gallons (liters) 40 (151) 40 (151) 55 (208) 98 (371)
Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) 152 (1048)
Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068) 300 (2068)
Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2
263.4 x 83.4 x 92.5
(6690 x 2118 x 2350)
80 x 243
(2032 x 6172)
14.0 – 95.5
(356 - 2425)
80 x 243
(2032 x 6172)
263.4 x 83.4 x 92.5
(6690 x 2118 x 2350)
80 x 243
(2032 x 6172)
ALS MODEL NUMBER
80 x 243
(2032 x 6172)
14.0 – 95.5
(356 - 2425)
263.4 x 83.4 x 92.5
(6690 x 2118 x 2350)
80 x 243
(2032 x 6172)
(2032 x 6172)
16.0 – 96.8
(406 - 2459)
80 x 243
263.4 x 83.4 x 92.5
(6690 x 2118 x 2350)
80 x 243
(2032 x 6172)
20.0 – 99.7
(508 - 2532)
80 x 243
(2032 x 6172)
IOMM ALS-4 21
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