McQuay ALP-012D Installation Manual
Installation and Operation Manual
Packaged Air-Cooled Condensing Units
Models ALP-012D - ALP-019D
50 and 60 Hertz
IM 687
Group: Chiller
Part Number: 629950
Date: January 1997
Supersedes: None
© 1997 McQuay International
Table of Contents
INTRODUCTION.............................3
INSPECTION ...................................3
INSTALLATION..............................3
Handling....................................................3
Location.....................................................4
Service Access...........................................5
Refrigerant Piping ............................5
General......................................................5
Refrigerant Piping .....................................5
Application Considerations..............6
Water Piping .............................................. 8
Flow Switch ............................................. 10
Initial Start-up................................11
Holding Charge ....................................... 11
Leak Testing............................................ 11
Evacuation............................................... 11
Charging The System............................... 11
Refrigerant Charge ..................................12
Pre-Startup ..............................................12
Startup ..................................................... 13
Dimensional Data............................14
Physical Data................................... 16
Field Wiring....................................19
Electrical Legend.....................................21
Normal Sequence Of Operation.....22
Startup.....................................................22
Pumpdown...............................................22
System Maintenance .......................23
General....................................................23
Fan Motor Bearings .................................23
Electrical Terminals.................................23
Condensers ..............................................23
Refrigerant Sightglass..............................23
Service.............................................24
Thermostat Expansion Valve....................24
Filter-Driers.............................................24
Liquid Line Solenoid................................24
Standard Controls ..........................25
High Pressure Control..............................25
Low Pressure Control ...............................25
Compressor Lockout ................................25
Compressor Motor Protector ....................26
Fantrol Head Pressure Control .................26
Optional Controls...........................27
Speedtrol Head Pressure Control..............27
Low Ambient Start...................................27
Hot Gas Bypass........................................27
Electrical Data................................. 17
“McQuay” is a registered trademarks of McQuay International.
©1997 McQuay International
“Illustrations cover the general appearance of McQuay International products at the time of publication and
we reserve the right to make changes in design and construction at anytime without notice.”
2 ALP 012D through 019D IM 687
Troubleshooting Chart....................29
INTRODUCTION
ALP air-cooled condensing units are designed for outdoor installations and are compatible with
either air handling units or chilled water evaporators. Each unit is completely assembled and
factory wired before evacuation, charging and testing. Each unit consists of an air-cooled condenser
with integral subcooler section, tandem scroll compressors, complete discharge piping and suction
and liquid connections for connect to any air or water cooling evaporator.
INSPECTION
When the equipment is received, check all items against the bill of lading and inspect for damage
upon arrival. Report all shipping damage to the carrier and file a claim. In most cases, equipment
is shipped fob factory and claims for freight damage should be filed by the consignee. Check the
unit serial plate before unloading the unit to be sure that it agrees with the power supply available.
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
Be careful to avoid rough handling of the unit. Do not push or pull the unit from anything other
than the base. Block the pushing vehicle away from the unit to prevent damage to the sheet metal
cabinet and end frame See Figure 1.
Figure 1, Suggested pushing arrangement
Blocking required
across full width
Lifting slots are provided in the base of the unit. Arrange spreader bars and cables to prevent
damage to the condenser coils or cabinet). See Figure 2.
IM 687 ALP 012D through 019D 3
Figure 2, Suggested lifting arrangement
Spreader bars
recommended
(Use Caution)
Location
Unit Placement
ALP units are for outdoor applications and can be mounted on a roof or ground level. Set units on a
solid and level foundation. For roof mounted
applications, install the unit on a steel channel or Ibeam frame to support the unit above the roof. For
ground level applications, install the unit on a
substantial base that will not settle. A one piece
concrete slab with footings extended below the frost
line is recommended. Be sure the foundation is
level (within 1/2” [13 mm] over its length and
width). The foundation must support the operating
weights listed in the Physical Data tables beginning
on
page 16.
NOTE: Number of fans can vary
from this diagram. Lifting method
remains the same.
Must use these rigging holes.
(Be aware of contol box location.)
On ground level applications protect fins
against vandalism using the optional coil guards or
by erecting a screen fence. The fence must allow
free flow of air to the condenser coil for proper unit
operation.
Unit operation is affected by wind. Located the
unit so length is parrallel with the prevailing wind.
If this is not practical, use wind deflectors.
Clearances
The flow of air to and from the condenser coil must
not be limited. Restricting air flow or allowing air
recirculation will result in a decrease in unit
performance and efficiency. There must be no
obstruction above the unit that would deflect
discharge air downward where it could be
recirculated back to the inlet of the condenser coil. The condenser fans are propeller type and will
not operate with ductwork on the fan outlet.
4 ALP 012D through 019D IM 687
Install the unit with three feet of side clearance for air entrance to the coil and for servicing.
Provide four feet of service access at each end to access the evaporator, compressors, electrical
control panel and piping components.
Do not allow debris to accumulate near the unit. Air movement may draw debris into the
condenser coil causing air starvation. Give special consideration to low ambient operation where
snow can accumulate. Keep condenser coils and fan discharge free of snow or other obstructions to
permit adequate airflow.
Service Access
Each end of the unit must be accessible after installation for periodic service. Compressors, filterdriers, and manual liquid line shutoff valves are accessible from the end of the unit. High pressure,
low pressure, and motor protector controls are on the compressor. Most operational, safety and
starting controls are located in the unit control box.
The condenser fan and motors can be removed from the top of the unit.
Refrigerant Piping
General
Piping design, sizing and installation information presented in ASHRAE Handbooks should, where
applicable, be followed in the design and installation of piping. ALP condensing units are adaptable
to either chilled water or air handling air conditioning applications. The only restriction on
applications is that the evaporator be selected for a system using refrigerant R-22.
Refrigerant Piping
Design and install piping between the condensing unit and the cooling coil to minimize pressure
drop, prevent liquid refrigerant carryover to the compressor and to assure a continuous return of
compressor oil from the system. Piping sketches and tables are not intended to provide information
on all of the possible arrangements.
Piping recommendations include:
1. The use of type K or L clean copper tubing. Thoroughly clean and braze all joints with high
temperature solder.
2. Piping sizes should be based on temperature/pressure limitations as recommended in the
following paragraphs. Under no circumstances should pipe size be based upon the coil or
condensing unit piping connection size.
3. Suction line pressure drop should not exceed the pressure equivalent of 2° (3 psi) per 100 feet of
equivalent pipe length. After the suction line size has been determined, the vertical suction
risers should be checked to verify that oil will be carried up the riser and back to the
compressor. The suction line should be pitched in the direction of refrigerant flow and
adequately supported. Lines should be free draining and fully insulated between the evaporator
and the compressor. Table 3, shows piping information for units operating at suction
temperatures between 40°F and 45°F and a condenser entering air temperature of 95°F. If
operating conditions are expected to vary substantially from these operating levels, the pipe
sizing should be rechecked.
4. Vertical suction risers should be checked using Table 1 to determine the minimum tonnage
required to carry oil up suction risers of various sizes.
5. The liquid line should be sized for a pressure drop not to exceed the pressure equivalent of 2°F
(6 psi) saturated temperature.
IM 687 ALP 012D through 019D 5
Table 1. Minimum tonnage to carry oil up suction riser at 40°°F saturated suction.
Line Size 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8
Min. Tons 1.50 2.50 3.80 7.60 13.10 20.40 29.70 41.30
NOTE: When compressor minimum tonnage is less than shown in the above table for a given line size, reselection of risers will be
required or hot gas bypass at the coil will be required.
Table 2, Recommended line sizes (Max. equivalent feet of copper tubing*)
MODEL
NUMBER
1 3/8” 1 5/8” 2 1/8” 5/8” 7/8” 1 1/8’
012D 70 160 -- 35 200 -015D 35 80 300 16 100 365
019D -- 50 180 -- 60 220
*Equivalent line lengths in the above table are suitable for a unit operating at 40°F sat. suction, 50°F return gas and 95°F ambient.
SUCTION
LINE SIZE
O.D. COPPER
LIQUID
LINE SIZE
O.D. COPPER
Table 3. Equivalent feet of straight tubing for copper fittings and valves
FITTING TYPE 5/8” 7/8” 1 1/8” 1 3/8” 1 5/8” 2 1/8” 2 5/8” 3 1/8” 3 5/8” 4 1/8”
ELBOWS
90° Standard
90° Long Radius
90° Street
45° Standard
45° Street
180° BEND
TEES
Full Size 1.0 1.4 11.7 2.3 2.6 3.3 4.1 5.0 5.9 6.7
Reducing 1.6 2.0 2.6 3.3 4.0 5.0 6.0 7.5 9.0 10
VALVES
Globe Valve, Open 18 22 29 38 43 55 69 84 100 120
Gate Valve, Open 0.7 0.9 1.0 1.5 1.8 2.3 2.8 3.2 4.0 4.5
Angle Valve, Open 7. 9. 12 15 18 24 29 35 41 47
Notes:
1. Liquid and suction lines based on a recommended equivalent pressure drop of 2°F (3 psi for suction line, 6 psi for liquid line)
per 100 ft. of equivalent length.
2. When the refrigerant required to charge a system exceeds the pumpdown capacity of the unit plus the capacity of the liquid
line (see Table 4), the use of separate refrigerant storage receiver will be required. The pumpdown capacity of each unit is
based on the condenser 90% full at 90°F (see physical data).
3. Total equivalent feet for a given piping layout must include the equivalent length of straight pipe for fittings, valves and
specialties added to the total run of straight pipe.
4. Piping design, sizing an installation information presented in ASHRAE Handbooks should, where applicable, be followed in the
design and installation piping.
5. Units running at 50% load do not require double suction risers.
1.6 2.0 2.6 3.3 4.0 5.0 6.0 7.5 9.0 10
1.0 1.4 1.7 2.3 2.6 3.3 4.1 5.0 5.9 6.7
2.5 3.2 4.1 5.6 6.3 8.2 10. 12 15 17
0.8 0.9 1.3 1.7 2.1 2.6 3.2 4.0 4.7 5.2
11.3 1.5 2.1 3.0 3.4 4.5 5.2 6.4 7.3 8.5
2.5 3.2 4.1 5.6 6.3 8.2 10 12 15 17
Application Considerations
Suction Accumulators
Field experience indicates that as the refrigerant charge in a small tonnage system increases, the
potential stress level from liquid floodback during system startup and stabilization also increases.
Since there is no factory control of condensing unit applications, piping and design, a suction
accumulator is recommended. The accumulator’s function is to intercept liquid refrigerant before it
reaches the compressor crankcase causing mechanical damage. It should be located in the suction
line between the evaporator and compressor, have a refrigerant capacity large enough to hold the
maximum amount of refrigerant that could flood through, and must have provisions for a positive
return of oil to the crankcase.
VAV Direct Expansion Systems
Variable air volume (VAV) application to direct expansion cooling coil systems is increasingly
attractive because of the potential energy savings in fan motor power. Extra care must be exercised
in the design of VAV direct expansion systems because of the potential for coil icing, oil trapping,
loss of stable expansion valve control, excessive compressor cycling, and nuisance operation of
protective controls.
6 ALP 012D through 019D IM 687
Equipment damage and nuisance tripping can be avoided by proper total system design. Special
consideration must be given to reduced load operating conditions as well as peak design, and coil
selection, capacity unloading, and system control modified as required to provide a trouble-free
system.
Head Pressure Control
Condenser coils on these ALP condensing units are vertical in position and are subject to wind. The
standard head pressure control offered controls the operation or speed of condenser fans. This type
of control has no effect if condenser coils are subjected to wind.
The design engineer or contractor has the responsibility of locating the equipment or protecting
the condenser coil so that prevailing winds have minimum effect on unit performance.
Oil Charge
Excessive piping or refrigerant charge or both may require the addition of some oil to the
compressor. If additional oil is required, use Suniso brand for the Copeland compressors. Add only
enough oil to maintain an oil level at the indicated point in the compressor sightglass.
Figure 3, Single Circuit Evaporator—Recommended Piping
Figure 4, Recommended Liquid Line Piping
IM 687 ALP 012D through 019D 7
Table 4, Weight of R-22 in copper lines (Pounds Per 100 feet of type L tubing)
LINE SIZE
O.D.(in.)
3/8 0.054 3.84 0.202 0.052 0.077
1/2 0.100 7.12 0.374 0.096 0.143
5/8 0.162 11.5 0.605 0.156 0.232
7/8 0.336 24.0 1.26 0.323 0.480
1 1/8 0.573 40.8 2.14 0.550 0.820
1 3/8 0.872 62.1 3.26 0.839 1.25
1 5/8 1.237 88.0 4.62 1.19 1.77
2 1/8 2.147 153.0 8.04 2.06 3.06
2 5/8 3.312 236.0 12.4 3.18 4.72
3 1/8 4.728 336.0 17.7 4.55 6.75
3 5/8 6.398 456.0 24.0 6.15 9.14
4 1/8 8.313 592.0 31.1 8.00 11.19
VOL PER 100
FT (CU, FT)
LIQUID @
100°F
WEIGHT OF REFRIGERANT (LBS)
HOT GAS @
120°F
SUCTION GAS
@20°F
SUCTION GAS
@ 40°F
Liquid Line Components
Liquid line components should include:
1. Filter-drier
2. Refrigerant solenoid valve/115 volt coil
3. Refrigerant sightglass/moisture indicator
4. Expansion valve/R-22
5. Manual shutoff valve
All liquid line components are field supplied and should be selected and installed according to good
field piping practices, ASHRAE Guide, and individual component manufacturer recommendations.
Hot Gas Bypass Components
Hot gas bypass kits are available for each ALP unit size. Each kit includes a solenoid valve, a hot
gas bypass valve and instruction drawing. See page 8 for hot gas bypass operation.
Table 5, Hot Gas Bypass Kits
ALP UNIT SIZE KIT NUMBER LINE SIZE O.D. (IN.)
012D 550443A-03 5/8
015D & 019D 550443A-04 7/8
Refrigerant Piping Connections
Refrigerant piping connections will be made at the compressor end of the unit. Suction and liquid
lines should be routed through the compressor enclosure on the side of the unit.
Water Piping
The following section applies to remote mounted DX water chillers.
Local authorities can supply the installer with the proper building and safety codes required for safe
and proper installation.
Install piping with minimum bends and changes in elevation to minimize pressure drop.
Consider the following when installing water piping:
1. Vibration eliminators to reduce vibration 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. Install drains at the
lowest points in the system.
4. A means of maintaining adequate system water pressure (expansion tank or regulating valve).
8 ALP 012D through 019D IM 687
5. Temperature and pressure indicators located at the unit to aid in unit servicing.
6. A strainer or other means of removing foreign matter from the water before it enters the pump.
Place the strainer 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 keep
system performance up.
7. Place a strainer in the water line just before the inlet of the evaporator. This will help prevent
foreign material from entering and decreasing the performance of the evaporator.
CAUTION
If separate disconnect is used for the 110V supply to the evaporator heating cable, mark
the disconnect clearly to ensure disconnect is not accidentally shut off during cold seasons.
8. The brazed plate evaporator has a thermostat and heating cable to prevent freeze-up down to 20°F (-29°C). It is suggested that the heating cable be wired to a separate 110V supply circuit.
As shipped from the factory, the heating cable is wired to the control circuit. All 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, flush the
system thoroughly before unit installation. Regular water analysis and chemical water
treatment on the evaporator is recommended immediately at equipment start-up.
10. The total water volume in the system should be sufficient to prevent frequent “on-off” cycling.
Turnover rate should not be less than 15 minutes for normal variable cooling loads. Turnover
rate for process cooling or a constant load,should not be less than 6 minutes.
11. When glycol is added to the water system for freeze protection, the refrigerant suction pressure
will be lower, cooling performance less, and water side pressure drop greater. If the percentage
of glycol is high, or if propylene is used instead of ethylene glycol, the added pressure drop and
loss of performance could be substantial. Reset the freezestat and low leaving water alarm
temperatures. The freezestat is factory set to default at 36°F (2.2°C). Reset the freezestat
setting to approximately 4 to 5 degress F (2.3 to 2.8 degress C) below the leaving chilled water
setpoint temperature. See the section titled “Glycol Solutions” for additional information
concerning glycol.
12. Perform a preliminary leak check before insulating the piping and filling the system.
13. Piping insulation should include a vapor barrier to prevent condensation and possible damage
to the building structure.
Figure 5, Typical field evaporator water piping
Vent
Outlet
Vibration
Drain
Vibration
Eliminator
Valved
pressure
gauge
Water
strainer
Eliminator
Gate valve
IM 687 ALP 012D through 019D 9
Flow
Balancing
Switch
Protect all field piping
against freezing
valve
Gate valve
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