Installation, Operation and Maintenance Manual
IOM ACAQ-1
Air-Cooled Condensers
Type ACS 010 Through ACS 100
Type ACD 045 Through ACD 210
Type AQS 020 Through AQS 085
Type AQD 040 Through AQD 170
Group: Chiller
Part Number: 331375101
Effective: January 2005
Supersedes: IOM ACAQ
Table of Contents
Product Offering ...............................................................................................................3
Introduction.......................................................................................................................4
Installation.........................................................................................................................4
Inspection.................................................................................................................................................. 4
Handling....................................................................................................................................................4
Holding Charge.........................................................................................................................................5
Unit Location.............................................................................................................................................5
Sound Vibration.........................................................................................................................................5
Walls or Obstructions................................................................................................................................ 6
Multiple Units ........................................................................................................................................... 7
Units in Pits............................................................................................................................................... 7
Decorative Fences.....................................................................................................................................7
Refrigerant Piping............................................................................................................. 8
Refrigerant Piping.....................................................................................................................................9
Discharge Lines......................................................................................................................................... 9
Physical Data ...................................................................................................................10
Electrical Data.................................................................................................................11
Operation .........................................................................................................................21
Start-Up................................................................................................................................................... 21
Discharge Gas Pulsation..........................................................................................................................21
Discharge Pressure Control.....................................................................................................................21
Maintenance..................................................................................................................... 26
Cleaning Instructions............................................................................................................................... 26
Manufactured in an ISO certified facility
2004 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 Air-cooled Condensers IOM ACAQ -1
Product Offering
Model
ACS - 1140 rpm fan motors, single row of fans
ACD - 1140 rpm fan motors, double row of fans
AQS - 830 rpm fan motors, single row of fans
AQD - 830 rpm fan motors, double row of fans
Size
ACS 010 through ACS 100
ACD 045 through ACD 210
AQS 020 through AQS 085
AQD 040 through AQD 170
Voltage Option
42 = 208/230/ 60/ 3
27 = 460/ 60/ 3
37 = 575/ 60/ 3
Special – 208/ 60/ 1, 208/230/380/460/50/3
Control Option
A = Fan pressure control with control transformer (120V)
B = SpeedTrol and pressure control with control transformer (120V)
C = SpeedTrol
Y = None
Rough Duty Option
A = Totally enclosed motors
B = SealTite Wiring, special water tight conduit system
C = PolyGuard fin coating with totally enclosed motors and SealTite wiring
D = ElectroFin coating with totally enclosed motors and SealTite wiring
IOM ACAQ -1 Air-cooled Condensers 3
Introduction
Carefully check each shipment against the bill of lading and account for all items. Report
any shortage or damage to the delivering carrier.
Be careful to prevent damage when uncrating. Heavy equipment should be left on unit’s
shipping base until it has been moved to the final location.
This equipment must be installed in accordance with accepted industry standards. Failure
to meet the following conditions may void the warranty:
1. System piping must be installed following industry standards for good piping practices.
2. Inert gas must be charged into piping during welding.
3. System must be thoroughly leak checked and evacuated before initial charging. High
4. Power supply to system must meet the following conditions:
5. All controls and safety switch circuits properly connected per wiring diagram.
6. Factory installed wiring must not be changed without written factory approval.
7. Relief valves must meet all code requirements.
vacuum gauge capable of reading microns is mandatory. Dial indicating pressure
gauges are not acceptable.
S Voltage for 208/230 motors not less than 195 volts or more than 253 volts.
S All other voltages must be within 10% of nameplate ratings.
S Phase imbalance not to exceed 2%.
Installation
Inspection
When the equipment is received, carefully check all items against the bill of lading to check
for a complete shipment. Check all units for damage upon arrival. All shipping damage
must be reported to the carrier and a claim must be filed with the carrier. Check the unit’s
serial plate 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.
Handling
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.
Avoid rough handling shock due to impact or dropping the unit. Do not push or pull the
unit.
Never allow any part of the unit to fall during unloading or moving, as this can result in
serious damage.
DANGER
Improper lifting or moving unit can result in property damage, severe
personal injury or death. Follow rigging and moving instructions carefully.
4 Air-cooled Condensers IOM ACAQ -1
Holding Charge
The unit is shipped with a holding charge of dry nitrogen under nominal pressure.
Unit Location
Units are designed for outdoor application and may be mounted on a roof or concrete slab
(ground level installation). Install roof mounted units on steel channels or an I-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 operating weight of the unit. For ground level
installation, mount units on a one-piece concrete slab with footings extending below the
frost line. Be certain concrete slabs are installed level and are properly supported to
prevent settling. Locate the condenser far enough away from any wall or other obstruction
to provide sufficient clearance for air entrance. Do not attach ductwork to the coil inlet or
fan outlet. Avoid air recirculation conditions that may be caused by sight screening, walls,
etc. and keep unit fan discharge away from any building air intakes. Do not install unit
where exhaust or ventilation equipment will affect entering air temperature or foul coils.
Sound Vibration
Install units away from occupied spaces, utility areas, corridors and auxiliary spaces to
reduce the transmission of sound and vibration to occupied spaces. The refrigerant piping
should be flexible enough to prevent the transmission of noise and vibration from the unit
into the building. If the refrigerant lines are to be suspended from the structure of the
building, use isolation hangers to prevent the transmission of vibration. Where piping
passes through a wall, pack fiberglass and sealing compound around the lines to minimize
vibration and retain flexibility. The unit must be secured in its final location. Holes are
provided in the base runner for this purpose.
IOM ACAQ -1 Air-cooled Condensers 5
Figure 1, Unit Rigging
Walls or Obstructions
Locate the unit to ensure air can
circulate freely and not be recirculated.
For proper air flow and access all sides
of the unit must be separated from the
wall as shown to the right. Increase
this distance whenever possible. Be
sure enough room is left for
maintenance through access doors and panels. Overhead obstructions are not permitted.
When enclosed by three walls the unit must be installed as indicated for units in a pit.
6 Air-cooled Condensers IOM ACAQ -1
AIR FLOW
ACS/ACD = 4 ft.
AQS/AQD = 6 ft.
Multiple Units
A
For units placed side by side, the
minimum distance between units
must be as shown to the right. If
units are placed end to end, the
minimum distance between units is
4 feet.
Units in Pits
The top of the unit should not be
more than two feet below top of the
pit, and side distance should be as
shown. If the top of the unit is not
level with the top of pit, discharge
cones or stacks must be used to raise
discharge air to the top of the pit.
This is a minimum requirement.
AIR FLOW
STACK
(BY OTHERS
IF SUPPLIED)
ACS/ACD = 4 ft.
AQS/AQD = 6 ft.
ACS/ACD = 6 ft.
AQS/AQD = 8 ft.
AIR
FLOW
AIR FLOW
2 FT. MAX.
ACS/ACD = 4 ft.
AQS/AQD = 6 ft.
Decorative Fences
Fences must have 50% free area,
with 1 foot undercut, at least the
width of condenser minimum
clearance, and must not exceed the
top of unit. If these requirements are
not met, unit must be installed as
indicated for "Units in pits".
1 IN.
MIN.
ACS/ACD
= 3 ft.
AQS/AQD
= 4 ft.
AIR FLOW
CS/ACD
= 3 ft.
AQS/AQD
= 4 ft.
IOM ACAQ -1 Air-cooled Condensers 7
Refrigerant Piping
Figure 2 illustrates a typical piping arrangement involving a remote condenser located at a
higher elevation, as commonly encountered when the condenser is on a roof and the
compressor and receiver are on grade level or in a basement equipment room. In this case,
the design of the discharge line is very critical. If properly sized for full load condition, the
gas velocity might be too low at reduced loads to carry oil up through the discharge line and
condenser coil. Reducing the discharge line size would increase the gas velocity
sufficiently at reduced load conditions; however, when operating at full load, the line would
be greatly undersized, and thereby create an excessive refrigerant pressure drop. This
condition can be overcome in one of two following ways:
1. Size discharge line for the desired pressure drop at full load conditions and install an oil
separator at the bottom of the trap in the discharge line from the compressor.
2. Use a double riser discharge line as shown in Figure 3. Size line "A" to carry the oil at
minimum load conditions and size line "B" at full load conditions; both lines would
have sufficient flow velocity to carry the oil to the condenser.
For more complete information, see the ASHRAE Handbook on Systems.
Be aware of the following when fabricating piping:
• All oil traps are to be as short in radius as possible. The trap may be fabricated using
three 90 degree ells.
• Use pressure relief valves at the condenser to protect the coil.
• Use a drain line check valve when the condenser is at a lower temperature than the
receiver.
Figure 2, Typical Piping Arrangement
Figure 3, Double Riser Discharge Piping
8 Air-cooled Condensers IOM ACAQ -1
Refrigerant Piping
Install piping according to standard accepted refrigeration practice. See Table 1 and Table 2
for discharge and liquid drain line sizes for remote condenser connections. Use only
refrigeration grade copper tubing and put dry nitrogen through lines while brazing.
CAUTION
Do not use soft solder joints. Do not leave dehydrated piping or com ponents open
to the atmosphere any longer than is absolutely necessary.
Valves
Major components should be equipped with isolation valves and a relief valve should be
installed in the discharge line between the check valve and the condenser inlet isolation
valve.
Discharge Lines
Design discharge lines so that refrigerant pressure drop is minimized (high pressure losses
cause increased compressor horsepower per ton of refrigerant) and a sufficiently high gas
velocity to carry oil through to the condenser coil and receiver at all loading conditions is
maintained.
Table 1, Discharge Line Sizing
Line Size
Type L
Copper
OD
1/2
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
Notes:
1. Source: ASHRAE Refrigeration Handbook:
2. Line sizes based on pressure drop equivalent to 1'F per 100 equivalent f eet
3. Values in Table are based on 1051F condensing temperature. Multiply Table capacities by the factors in
Table 2 for other condensing temperat ures.
4. If subcooling is substantial or the li ne i s short, a smaller li ne size may be used. Applications with very littl e
subcooling or very long lines may require larger sizes.
Sat. Suction Temp. (°F) Sat. Suction Temp. (°F)
-40 0 40 -40 0 40 R-22 R-502
0.75 0.8 0.85 0.56 0.63 0.7 2.3 1.5
1.4 1.5 1.6 1.0 1.2 1.3 3.7 2.3
3.7 4.0 4.2 2.7 3.1 3.4 7.8 4.9
7.5 8.0 8.5 5.5 6.3 7.0 13.2 8.3
13.1 14.0 14.8 9.6 10.9 12.1 20.2 12.6
20.7 22.0 23.4 15.2 17.2 19.1 28.5 17.9
42.8 45.7 48.5 31.4 35.6 39.5 49.6 31.1
75.4 80.4 85.4 55.3 62.8 69.5 76.5 48.0
120.2 128.2 136.2 87.9 99.8 110.5 109.2 68.4
178.4 190.3 202.1 130.5 148.1 164.0 147.8 92.6
251.1 267.8 284.4 183.7 208.4 230.9 192.1 120.3
R-22 R-404A, R-507
Discharge Line
Drain Line
Velocity 100 FPM
Refrigerant
Table 2, Condensing Temperature Correction Factor
Condensing
Temperature
90
100
110
120
130
IOM ACAQ -1 Air-cooled Condensers 9
Discharge Line
R-22 R-404, R-507
0.88 0.91
0.95 -0.97
1.04 1.02
1.10 1.08
1.18 1.16
Physical Data
Table 3, Model ACS Physical Data
Number
010A
012A
016A
020A
030A
035A
045A
050A
060A
065A
070A
085A
100A
Table 4, Model ACD Physical Data
Number
045A
060A
065A
085A
100A
115A
130A
140A
165A
175A
200A
210A
Number
of Fans
Number
of Fans
Rows/
2 3/12 1-1/8 7/8 450 500 7 26
2 3/12 1-3/8 7/8 470 520 7 26
2 4/12 1-3/8 7/8 530 580 12 44
2 2/12 1-3/8 1-1/8 730 800 8 28
2 3/12 1-5/8 1-1/8 770 840 12 44
2 4/12 1-5/8 1-1/8 880 950 15 57
3 3/12 2-1/8 1-3/8 1,190 1,280 19 66
3 4/12 2-1/8 1-3/8 1,240 1,330 22 84
4 3/12 2-1/8 1-3/8 1,580 1,690 29 124
4 4/12 2-1/8 1-5/8 1,650 1,760 36 163
5 3/12 2-1/8 1-5/8 2,020 2,150 35 154
5 4/12 2-5/8 1-5/8 2,080 2,225 43 201
6 4/12 2-5/8 1-5/8 2,390 2,610 50 240
Rows/
4 2/12 (2) 1-3/8 (2) 1-1/8 1,540 1,730 16 56
4 3/12 (2)1-5/8 (2) 1-1/8 1,580 1,770 24 88
4 4/12 (2)1-5/8 (2) 1-1/8 1,650 1,840 30 114
6 3/12 (2) 2-1/8 (2) 1-3/8 2,380 2,620 38 132
6 4/12 (2) 2-1/8 (2) 1-3/8 2,480 2,690 44 168
8 3/12 (2) 2-1/8 (2) 1-3/8 3,150 3,360 58 248
8 4/12 (2) 2-1/8 (2) 1-5/8 3,300 3,470 72 326
10 3/12 (2) 2-1/8 (2) 1-5/8 4,040 4,290 70 308
10 4/12 (2) 2-5/8 (2) 1-5/8 4,130 4,450 86 402
10 4/14 (2) 2-5/8 (2) 1-5/8 4,390 4,680 86 402
12 4/12 (2) 2-5/8 (2) 1-5/8 4,960 5,330 100 480
12 4/14 (2) 2-5/8 (2) 1-5/8 5,270 5,670 100 480
FPI
FPI
Connection (Inches)Model
In Sub-Out
Connection Model
In Sub-Out
Approx.
Weight (Lb)
Approx.
Weight (Lb)
Ship
Weight (Lb)
Ship
Weight (Lb)
Operating
Charge, R-22
Operating
Charge, R-22
Pumpdown
Capacity, R-22
Pumpdown
Capacity, R-22
Table 5, Model AQS Physical Data
Number
020A
025A
030A
040A
045A
050A
055A
065A
070A
085A
Number
Of Fans
Rows/
FPI
2 2/12 1-3/8 1-1/8 730 800 8 28
2 3/12 1-5/8 1-1/8 770 840 12 44
2 4/12 1-5/8 1-1/8 880 950 15 57
3 3/12 2-1/8 1-3/8 1190 1280 19 66
3 4/12 2-1/8 1-3/8 1240 1330 22 84
4 3/12 2-1/8 1-3/8 1580 1690 29 124
4 4/12 2-1/8 1-5/8 1650 1760 36 163
5 3/12 2-1/8 1-5/8 2020 2150 35 154
5 4/12 2-5/8 1-5/8 2080 2225 43 201
6 4/12 2-5/8 1-5/8 2390 2610 50 240
Connection Model
In Sub-Out
Table 6, Model AQD Physical Data
Number
040A
050A
055A
075A
085A
100A
115A
125A
140A
170A
Number
Of Fans
Rows/
FPI
4 2/12 (2) 1-3/8 (2) 1-1/8 1540 1730 16 56
4 3/12 (2)1-5/8 (2) 1-1/8 1580 1770 24 88
4 4/12 (2)1-5/8 (2) 1-1/8 1650 1840 30 114
6 3/12 (2) 2-1/8 (2) 1-3/8 2380 2620 38 132
6 4/12 (2) 2-1/8 (2) 1-3/8 2480 2690 44 168
8 3/12 (2) 2-1/8 (2) 1-3/8 3150 3360 58 248
8 4/12 (2) 2-1/8 (2) 1-5/8 3300 3470 72 326
10 3/12 (2) 2-1/8 (2) 1-5/8 4040 4290 70 308
10 4/12 (2) 2-5/8 (2) 1-5/8 4130 4450 86 402
12 4/12 (2) 2-5/8 (2) 1-5/8 4390 4680 86 402
Connection Model
In Sub-Out
Approx.
Weight (Lb)
Approx.
Weight (Lb)
Ship
Weight (Lb)
Ship
Weight (Lb)
Operating
Charge, R-22
Operating
Charge, R-22
Pumpdown
Capacity, R-22
Pumpdown
Capacity, R-22
10 Air-cooled Condensers IOM ACAQ -1
Electrical Data
Install all electrical wiring according to the National Electrical Code, local codes and
regulations. Use copper conductors only. All standard motors have internal inherent overload
protectors, allowing contactors to be used instead of starters requiring thermal protectors.
There may be more than one source of electrical current in this unit. Do not service
All condensers are furnished with either single-phase or three-phase fan motors, which are
identified by the unit dataplate. Electrical leads from each motor terminate at the unit junction
box. Field connections must be made from these leads in accordance with local, state and
national codes. The motors are wired into a common junction box. Where fan cycling is
furnished and factory installed, the motors are completely wired through the control and to the
contactors. Check motors for proper rotation and be sure motor voltage and control voltage
agree with electric services furnished.
Table 7, Model ACS Electrical Data, 1140 RPM
Model
Number
010A
012A
016A
020A
030A
035A
045A
050A
060A
065A
070A
085A
100A
Fans
CFM
2 10,100 1/3 5.2 5.9 10 2.6 2.9 6 - - - 1/3 6.8 7.6 10
2 12,400 1/3 5.2 5.9 10 2.6 2.9 6 - - - 1/2 7.8 8.8 10
2 12,900 1/3 5.2 5.9 10 2.6 2.9 6 - - - 1/2 7.8 8.8 10
2 23,000 1-1/2 14.0 15.8 20 7.0 7.9 10 5.6 6.4 10 3/4 9.6 10.8 15
2 23,200 1-1/2 14.0 15.8 20 7.0 7.9 10 5.6 6.4 10 3/4 9.6 10.8 15
2 20,700 1-1/2 14.0 15.8 20 7.0 7.9 10 5.6 6.4 10 3/4 9.6 10.8 15
3 34,800 1-1/2 21.0 22.8 25 10.5 11.4 15 8.4 9.2 10 3/4 14.4 15.6 20
3 31,800 1-1/2 21.0 22.8 25 10.5 11.4 15 8.4 9.2 10 3/4 14.4 15.6 20
4 46,400 1-1/2 28.0 29.8 30 14.0 14.9 15 11.2 12.0 15 3/4 19.2 20.4 25
4 42,400 1-1/2 28.0 29.8 30 14.0 14.9 15 11.2 12.0 15 3/4 19.2 20.4 25
5 54,900 1-1/2 35.0 36.8 40 17.5 18.4 20 14.0 14.8 15 3/4 24.0 25.2 30
5 54,800 1-1/2 35.0 36.8 40 17.5 18.4 20 14.0 14.8 15 3/4 24.0 25.2 30
6 65,800 1-1/2 42.0 43.8 50 21.0 21.9 25 16.8 17.6 20 3/4 28.8 30.0 30
HP
WARNING
before disconnecting all power supplies.
208-230/3/60 460/3/60 575/3/60 208-230/1/60
TOTAL
FLA
MCA
Max
Fuse
TOTAL
FLA
MCA
Max
Fuse
TOTAL
FLA
MCA
Max
Fuse
HP
TOTAL
FLA
MCA
Fuse
Max
Table 8, Model ACD Electrical Data, 1140 RPM
Model
Number
045A
060A
065A
085A
100A
115A
130A
140A
165A
175A
200A
210A
Fans CFM
4 46,000 1-1/2 28.0 29.8 30 14.0 14.9 15 11.2 12.0 15 3/4 19.2 20.4 25
4 46,400 1-1/2 28.0 29.8 30 14.0 14.9 15 11.2 12.0 15 3/4 19.2 20.4 25
4 42,400 1-1/2 28.0 29.8 30 14.0 14.9 15 11.2 12.0 15 3/4 19.2 20.4 25
6 67,000 1-1/2 42.0 43.8 50 21.0 21.9 25 16.8 17.6 20 3/4 28.8 30.0 30
6 63,600 1-1/2 42.0 43.8 50 21.0 21.9 25 16.8 17.6 20 3/4 28.8 30.0 30
8 92,900 1-1/2 56.0 64.8 70 28.0 28.9 30 22.4 23.2 25 3/4 38.4 39.6 40
8 84,800 1-1/2 56.0 64.8 70 28.0 28.9 30 22.4 23.2 25 3/4 38.4 39.6 40
10 109,700 1-1/2 70.0 71.8 80 35.0 35.9 40 28.0 28.8 30 3/4 48.0 49.2 50
10 106,000 1-1/2 70.0 71.8 80 35.0 35.9 40 28.0 28.8 30 3/4 48.0 49.2 50
10 103,700 1-1/2 70.0 71.8 80 35.0 35.9 40 28.0 28.8 30 3/4 48.0 49.2 50
12 127,200 1-1/2 84.0 85.8 90 42.0 42.9 45 33.6 34.4 40 3/4 57.6 58.8 60
12 124,400 1-1/2 84.0 85.8 90 42.0 42.9 45 33.6 34.4 40 3/4 57.6 58.8 60
HP
IOM ACAQ -1 Air-cooled Condensers 11
208-230/3/60 460/3/60 575/3/60 208-230/1/60
TOTAL
FLA
MCA
Max
Fuse
TOTAL
FLA
MCA
Max
Fuse
TOTAL
FLA
MCA
Max
Fuse
HP
TOTAL
FLA
MCA
Fuse
Max
Table 9, Model AQS Electrical Data, 830 RPM
Model
Number
020A
025A
030A
040A
045A
050A
055A
065A
070A
085A
Fans
CFM
2 18400 1 9.6 10.8 15 4.8 5.4 10 4.0 4.5 10
2 18700 1 9.6 10.8 15 4.8 5.4 10 4.0 4.5 10
2 17800 1 9.6 10.8 15 4.8 5.4 10 4.0 4.5 10
3 28000 1 14.4 15.6 20 7.2 7.8 10 6.0 6.5 10
3 25900 1 14.4 15.6 20 7.2 7.8 10 6.0 6.5 10
4 37400 1 19.2 20.4 25 9.6 10.2 15 8.0 8.5 10
4 35500 1 19.2 20.4 25 9.6 10.2 15 8.0 8.5 10
5 45200 1 24.0 25.2 30 12.0 12.6 15 10.0 10.5 15
5 44400 1 24.0 25.2 30 12.0 12.6 15 10.0 10.5 15
6 53300 1 28.8 30.0 30 14.4 15.0 15 12.0 12.5 15
HP
NOTE: Single-phase motors are not available at 830 rpm.
208-230/3/60 460/3/60 575/3/60
TOTAL
FLA
MCA
Max
Fuse
TOTAL
FLA
Table 10, Model AQD Electrical Data, 830 RPM
Model
Number
040A
050A
055A
075A
085A
100A
115A
125A
140A
170A
Fans
CFM HP
4 36700 1 19.2 20.4 25 9.6 10.2 15 8.0 8.5 10
4 37400 1 19.2 20.4 25 9.6 10.2 15 8.0 8.5 10
4 35500 1 19.2 20.4 25 9.6 10.2 15 8.0 8.5 10
6 56000 1 28.8 30.0 30 14.4 15.0 15 12.0 12.5 15
6 51800 1 28.8 30.0 30 14.4 15.0 15 12.0 12.5 15
8 74700 1 38.4 39.6 40 19.2 19.8 20 16.0 16.5 20
8 71000 1 38.4 39.6 40 19.2 19.8 20 16.0 16.5 20
10 90500 1 48.0 49.2 50 24.0 24.6 25 20.0 20.5 25
10 88800 1 48.0 49.2 50 24.0 24.6 25 20.0 20.5 25
12 103200 1 57.6 58.8 60 28.8 29.4 30 24.0 24.5 25
208-230/3/60 460/3/60 575/3/60
TOTAL
FLA
MCA
Max
Fuse
TOTAL
FLA
MCA
MCA
Max
Fuse
Max
Fuse
TOTAL
FLA
TOTAL
FLA
MCA
MCA
Max
Fuse
Max
Fuse
NOTE: Single-phase motors are not available at 830 rpm.
Table 11, Motor Availability
Fan Speed 3-Phase 1-Phase
1140 RPM
830 RPM
NOTE: Multiply capacities by 0.77 for 1-phase motors due to smaller fan size.
12 Air-cooled Condensers IOM ACAQ -1
1 1/2 HP 1/3, 1/2, 3/4 HP
1.0 None
IOM ACAQ -1 Air-cooled Condensers 13
C
Q
S
S
G
Figure 4, Two - Four Fan, One Row, ACS/AQS, Wiring with Pressure Switch Fan Control
M
ADJUSTABLE RANGE (MINIMUM RANGE 125 - 250#)
(DIFFERENTIAL RANGE 20 - 100#)
115V
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURRENT PROTECTION
GND
FCP 1
FCP 2
FCP 3
FCP 4
FANS/CIRCUIT
2
3
4
T1 T2
TERMINAL
BOARD
C1
C2
C3
C4
FCP#1
190/140
190/140
190/140
UAY PRE
URE FAN CYCLIN
FCP#2
230/170
220/160
210/180
FCP#3 FCP#4
230/170
220/160
OPTION
TRANSFORMER
F7
3A-500V
SEE NOTE 5
FAN MOTOR IDENT I F ICATION
5
321
4
6
END
HEADER
ELECTR IC BOX
LEGEND:
C1-C4 FAN CONTACTOR
M1-M4 FAN MOTOR
FCP FAN CYCLE PRESSURE CONTROL
F1-F4 FUSES (REFER TO LABEL
ADJACENT TO FUSE HOLDER
FOR REPLACEMENT)
NOTE:
1. UNIT MUST BE GROUNDED
2. TO BE FIELD FUSED, REFER TO UNIT
DAT A PLATE FOR VOLTAGE
3. ALL MOT ORS ARE INHERENTLY PROTECTED
4. USE 60° C WIRE
5. WIRED ONLY WITH CONTROL CIRC UI T
TRANSFORMER OPTION
6. USE COPPER CONDUCTORS ONLY
230/170
GND
MAIN POWER CIRCUIT
3PH/50/60HZ
DOOR
DISCONNECT
SWITCH
T1
T2 T3
TERMINAL
BOARD
OPTION
TRANSFORMER
F2
F3
F4
C2
T3
L3
T2
L2
L1
T1
C3
L3
T3
T2
L2
L1
T1
C4
T3
L3
L2
T2
L1
T1
L3
L2
M2
L1
L3
L2
M3
L1
L3
L2
M4
L1
GND
L2
L1
24V
P66
GND
ELECTRONIC
FAN
L1
SPEED
M1
CONTROL
L2R
L1C
VARIABLE SPEED
M1
CONTROL MOT OR
S
14 Air-cooled Condensers IOM ACAQ -1
Figure 5, Four - Eight Fan, Two Row, ACD/AQD, Wiring with Pressure Swi t ch Fan Cont r o l
FAN MOTOR IDENTIFICATION
115V
CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURREN T PR OT E C T IO N
T1 T2
GND
TERMINAL
BOARD
12111098
ELECTRIC BOX
765
4
2
NOTE:
1
3
1. UNIT MUST BE GROUNDED
HEADER
END
2. TO BE FIELD FUSED, REFER TO
UNIT DATE PLATE FOR VOLT AGE
3. ALL MOTORS ARE INHERENTL Y
PROTECTED
4. USE 60° C WIRE
5. WIRED ONLY WITH CONTROL
CIRCUIT TRANSFORMER OPTION
6. USE COPPER CONDUCTORS ONLY
LEGEND:
C1-C8 FAN CONTACTOR
M1-M8 FAN MO TOR
FCP FAN CYCLE PRESSURE CONTROL
F1-F8 FUSES (REFER TO LABLE ADJACENT
TO FUSE HOLDER FOR REPLACEMENT)
OPTION
TRANSFORMER
SEE NOTE 5
F7
3A-500V
DOOR
DISCONNECT
SWITCH
TERMINAL
BOARD
MAIN POWER CIRCUIT
3PH/50/60HZ
L1
L2 L3
GND
T2 T3
T1
FCP 1
FCP 2
FCP 3
FCP 4
FCP 5
FCP 6
FCP 7
FCP 8
C1
C2
C3
C4
C5
C6
FANS/CIRCUIT
2
3
4
ADJUSTABLE RANGE (MINIMUM RANGE 125 -250#)
(DIFFERENTIAL RANGE 20 - 100#)
MCQUAY PRESSURE FAN CYCLING
FCP #1, #2
190/140
190/140
190/140
C7
C8
F8
C8
L2
L1
T1T2T3
L2
L1
M8
FCP #3, #4
F7
L3
C7 C6
L3
230/170
220/160
210/150
L2
L1
T1T2T3
L2
L1
M7
F6
L3
L3
F5
L3
L2
L1
C5 C4 C3
T1T2T3
L2
L1
L3
M6
FCP #5, #6
230/170
220/160
L2
L1
T1T2T3
L2
L1
M5
L3
L3
F4
L3
L2
L1
T1T2T3
L2
L1
L3
FCP #7, #8
230/170
F3
L2
L1
T1T2T3L3
L2
L1
M3M4
L3
F2
L2
L1
C2
T2
T1
L1C
L2R
S
M2
VARIABLE SPEED
CONTROL MOTOR
460V
OR
230V
INPUT
24V
L1
GND
P66
GND
L1
M1
ELECTRONIC
FAN
SPEED
CONTROL
TRANSFORMER
L2
L1
T1
L1C
S
M1
VARIABLE SPEED
CONTROL MOTOR
F1
C1
T2L2
L2R
GND
GND
L1
M1
ELECTRONIC
FAN
SPEED
CONTROL
OPTION
P66
Figure 6, Five Fan, One Row, ACS/AQS, Wiring with Pressure Switch Fan Control
OPTION
L2
TRANSFORMER
DOOR
DISCONNECT
SWITCH
MAIN POWER CIRCUIT
3PH/50/60HZ
L2 L3
L1
GND
L1
24V
460VOR230V
T3
T1 T2
ELECTRONIC
FAN
SPEED
CONTROL
VARIABLE SPEED
CONTROL MOTOR
L1
M1
GND
P66
GND
TERMINAL
BOARD
M1
S
L2R
L1C
M2
L3
T2
C1F1
L2
L1 T1
L2
T3
T2
C2
L2
L3
F2
M3
L3
L1
L2
T3
T2
T1
C3
L1
L2
L3
F3
M4
L3
L1
T1
L1
L1
L2
T1
T3
T2
C4
L1
L2
L3
F4
M5
L3
L1
L2
T1
T3
T2
C5
L1
L2
L3
F5
END
OPTION
F7
3A-500V
FCP#4
230/170
SEE NOTE 5
FCP#3
220/160
TRANSFORMER
FCP#2
210/150
FCP#1
190/140
MCQUAY PRESSURE FAN CYCLING
(DIFFERENTIAL RANGE 20 - 100#)
ADJUSTABLE RANGE (MINIMUM RANGE 125 - 250#)
5.6
FANS/CIRCUIT
115V
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURRENT PROTECTION
TERMINAL
BOARD
T2
T1
GND
HEADER
12
34
5
6
FAN MOTOR IDENTIFICATION
ELECTRIC BOX
LEGEND:
C1-C5 FAN CONTACTOR
M1-M5 FAN MOTOR
FCP FAN CYCLE PRESSURE CONTROL
F1-F5 FUSES (REFER TO LABEL
C1
FCP 1
C2
FCP 2
FCP 3
NOTE:
1. UNIT MUST BEE GROUNDED
2. TO BE FIELD FUSED, REFER
TO UNIT DATA PLATE FOR VOLTAGE
3. ALL MOTORS ARE INHERENTLY
PROTECTED
4. USE 60° C WIRE
5. WIRED ONLY WITH CONTROL CIRCUIT
TRANSFORMER OPTION
ADJACENT TO FUSE HOLDER
FOR REPLACEMENT)
C3
C4
FCP 4
6. USE COPPER CONDUCTORS ONLY
C5
IOM ACAQ -1 Air-cooled Condensers 15
Figure 7, Six Fan, One Row, ACS/AQS, Wiring with Pressure Switch Fan Control
C
Q
S
S
C
C
G
ELECTRONIC
FAN
SPEED
CONTROL
VARIABLE SPEED
OPTION
L1
M1
GND
P66
L2
L1
24V
GND
TRANSFORMER
460VOR230V
CONTROL MOTOR
M1
S
L2R
L1C
M2
L3
L1
T1
T2
L2
L1
L2
T1
T2
T3
C2
L1
L3
F1 C1
L2
M3
L3
L1
L2
T1
T2
T3
C3
L1
L3
L2
M4
L3
L1
L2
T2
T3
C4
L3
L2
M5
L3
T1
T3
L3
L1
L2
T1
T3
T2
C5
L1
L3
L3
L1
L2
M6
L1
L2
T1
T2
L1
L2
FCP#4
LIN
FCP#3
Y
URE FAN
FCP#2
UAY PRE
M
FCP#1
230/170
220/160
210/150
190/140
DOOR
DISCONNECT
SWITCH
MAIN POWER CIRCUIT
3PH/50/60HZ
L2 L3
L1
TERMINAL
BOARD
T2 T3
T1
F2
F3
F4
F5
F6 C6
GND
END
HEADER
OPTION
F7
3A-500V
SEE NOTE 5
TRANSFORMER
FAN MOTOR IDENTIFICATION
ELECTRIC BOX
LEGEND:
C1-C8 FAN CONTACTOR
M1-M6 FAN MOT OR
FCP FAN CYCLE PRES S URE CONTROL
F1-F6 FUSES (REFER TO LABEL
ADJACENT TO FUSE HO LD ER
FOR REPLACEMENT)
NOTE:
1. UNIT MUST BE GROUNDED
2. TO BE FIELD FUSED, REFER TO
UNIT DATA PLATE FOR VOLTAGE
3. ALL MOTORS ARE INHERENTL Y
PROTECTED
4. USE 60° C WIRE
5. WIRED ONLY WITH CONTROL
CIRCUIT TRANSFORMER OPTION
6. USE COPPER CONDUCTORS ONLY
5.6
ADJUSTABLE RANGE (MINIMUM RANGE 125 - 250#)
FANS/CIRCUIT
TERMINAL
(DIFFERENTIAL RANGE 20 - 100#)
115
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURRENT PROTECTION
BOARD
T1 T2
C1
FCP 1
C2
FCP 2
GND
C4
C3
FCP 3
C6
C5
FCP 4
16 Air-cooled Condensers IOM ACAQ -1
Figure 8, Ten Fan, Two Row, ACD/AQD, Wiring with Pressure Sw i tch Fan Control
OPTION
P66
L1
M1
GND
T3
L1 L2 L3
3PH/50/60HZ
MAIN POWER CIRCUIT
DOOR
DISCONNECT
SWITCH
T2
T1
TERMINAL
BOARD
TRANFORMER
460VOR230V
INPUT
F1
24V
F2
C1
L2
T2
L1
T1
L2
L1
C2
L2
T2
L1
T1
GND
GND
GND
ELECTRONIC
FAN
SPEED
CONTROL
L2R
L1C
M1
S
VARIABLE SPEED
CONTROL MOTOR
L1
M1
GND
ELECTRONIC
FAN
SPEED
P66
CONTROL
L2R
L1C
M2
S
VARIABLE SPEED
CONTROL MOTOR
L3
T3
L2
T2
L1
OPTION
F7
3A-500V
LEGEND:
C1-C10 FAN CONTACTOR
M1-M10 FAN MOTOR
FCP FAN CYCLE PRESSURE CONTROL
F1-F10 FUSES (REFER TO LABEL
ADJACENT TO FUSE HOLDER
FOR REPLACEMENT)
SEE NOTE 5
TRANSFORMER
NOTE:
1. UNIT MUST BE GROUNDED
2. TO BE FIELD FUSED, REFER TO UNIT
DATA PLATE FOR VOLTAGE
3. ALL MOTORS ARE INHERENTLY
PROTECTED
4. USE 60° C WIRE
5. WIRED ONLY WITH CONTROL CIRCUIT
TRANSFORMER OPTION
6. USE COPPER CONDUCTORS ONLY
END
HEADER
F3
F4F5F6
F7
F8
F9
F10
T1
C3
L3
T3
L2
T2
L1
T1
L3
T3
L2
T2
L1
T1
C5 C4
L3
T3
L2
T2
L1
T1
C6
L3
T3
L2
T2
L1
T1
C7
L3
T3
L2
T2
L1
T1
C8
L3
T3
L2
T2
L1
T1
C9
L3
T3
L2
T2
L1
T1
C10
L3
L2
M3
L1
L3
L2
L1
L3
L2
L1
L3
L2
M6 M5 M4
L1
L3
L2
M7
L1
L3
L2
L1
L3
L2
M9 M8
L1
L3
L2
M10
L1
230/170
FCP#7, #8
220/160
FCP#5, #6
210/150
FCP#3, #4
MCQUAY PRESSURE FAN CYCLING
190/140
FCP#1, #2
(DIFFERENTIAL RANGE 20 - 100#)
ADJUSTABLE RANGE (MINIMUM RANGE 125 - 250#)
5.6
FANS/CIRCUIT
FAN MOTOR IDENTIFICATION
ELECTRIC BOX
C4
TERMINAL
BOARD
T1 T2
115V
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURRENT PROTECTION
GND
C1
FCP 2
FCP 1
C3
C2
FCP 3
FCP 5
FCP 4
C6
C5
FCP 6
C9
C7
C8
C10
FCP 7
FCP 8
IOM ACAQ -1 Air-cooled Condensers 17
Figure 9, Twelve Fan, Two Row, ACD/AQD, Wiring with Pressur e Sw itch Fan Control
OPTION
P66
L1
M1
GND
C1
L2
T2
T1
L1
L2
L1
C2
L2
T2
T1
L1
TRANSFORMER
460VOR230V
INPUT
F1
24V
F2
L2 L3
L1
3PH/50/60HZ
T2 T3
T1
MAIN POWER CIRCUIT
TERMINAL
DOOR
DISCONNECT
SWITCH
BOARD
GND
GND
GND
ELECTRONIC
FAN
SPEED
CONTROL
L2 R
L1 C
M1
S
VARIABLE SPEED
CONTROL MOTOR
L1
M1
GND
ELECTRONIC
FAN
SPEED
L1 C
L2 R
CONTROL
M2
S
VARIABLE SPEED
CONTROL MOTOR
P66
L3
T3
L2T1T2
OPTION
F7
LEGEND:
C1-C12 FAN CONTACTOR
M1-M12 FAN MOTOR
FCP FAN CYCLE (R EF ER TO LABEL
ADJACENT TO FUSE HOLDER
FOR REPLACEMENT)
NOTE:
1. UNIT MUST BE GROUNDED
2. TO BE FIELD FUSE D, REFER TO
UNIT DATA PLATE FOR VOLTAGE
3. ALL MOTORS ARE INHER ENTL Y
PROTECTED
4. USE 60° C WIRE
5. WIRED ONLY WITH CONTROL
CIRCUIT TRANSFORMER OPTION
6. USE COPPER CONDUCTORS ONLY
END
HEADER
FAN MOTOR IDENTIFICATION
ELECTRIC BOX
3A-500V
SEE NOTE 5
TRANSFORMER
L1
F3
C3
L3
T3
L2
T2
T1
L1
F4
C4
L3
T3
T2
L1L2T1
F5
C5
L3
T3
T2
L1L2T1
C6
F6
L3
T3
L2T1T2
L1
F7
C7
L3
T3
T2
L1L2T1
F8
C8
L3
T3
T2
L1L2T1
F9
C9
L3
T3
T2
L1L2T1
F10
C10
L3
T3
L2T1T2
L1
F11
C11
L3
T3
T2
L1L2T1
F12
C12
L3
L2
M3
L1
L3
L2
M4
L1
L3
L2
M5M6
L1
L3
L2
L1
L3
L2
M7
L1
L3
L2
M8
L1
L3
L2
M9
L1
L3
L2
M10
L1
L3
L2
M11
L1
L3
L2
M12
L1
230/170
FCP#7, #8
220/160
FCP#5, #6
210/150
FCP#3, #4
190/140
MCQUAY PRESSURE FAN CYCLING
FCP#1, #2
(DIFFERENTI AL RANGE 20 - 1 00#)
ADJUSTABLE RANGE (MINIMUM RANGE 125 - 250#)
5.6
FANS/CIRCUIT
TERMINAL
BOARD
T2
T1
115V
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURRENT PROTECTION
FCP 1
C2
C1
FCP 3
FCP 2
C4
C3
FCP 4
GND
C7
C5
FCP 5
C9
C8
C6
FCP 6
C11
C10
C12
FCP 8
FCP 7
18 Air-cooled Condensers IOM ACAQ -1
IOM ACAQ -1 Air-cooled Condensers 19
OPTIO
N
Figure 10, Six Fan, One Row, ACS/AQS, Wiring with Contactors for Field Inst al led Control
MAIN POWER CIRCUIT
3PH/50/60HZ
OPTION
L1 L2 L 3
T2 T3
T1
DISCONNECT
SWITCH
TERMINAL
BOARD
F2 C2
F3
F4
F5 C5
F6
TRANSFORMER
L2
L1
460V
OR
230V
F1
C1
L2 T2
L1
T1
24V
GND
P66
GND
ELECTRONIC
FAN
L1
SPEED
CONTROL
M1
L2R
L1C
VARIABLE SPEED
M1
CONTROL MOTOR
S
L3
T3
T2
L2
L1
T1
C3
L3
T3
T2
L2
L1
T1
C4
L3
T3
T2
L2
L1
T1
L3
T3
T2
L2
L1
T1
C6
L3
T3
T2
L2
L1
T1
L3
L2
M2
L1
L3
L2
M3
L1
L3
L2
M4
L1
L3
L2
M5
L1
L3
L2
M6
L1
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
OVERCURRENT PROTECTION
TERMINAL BOARDS
FOR FIELD CONTROL
OF FAN CONTACTORS
TERMINAL
BOARD 1
TERMINAL
BOARD 2
TERMINAL
BOARD 3
TERMINAL
BOARD 4
TERMINAL
BOARD 5
TERMINAL
BOARD 6
TRANSFORMER
T2
C1
T1
T2
C2
T1
T2
C3
T1
T2
C4
T1
T2
C5
T1
T2
C6
T1
LEGEND:
C1-C6 FAN CONTACTOR
M1-M6 FAN MOTOR
FCP FAN CYCLE PRESSURE CONTROL
F1-F6 FUSES (REFER TO LABEL
ADJACENT TO FUSE HOLDER
FOR REPLACEMENT)
NOTE:
1. UNIT MUST BE GROUNDED
2. TO BE FIELD FUSED, REFER TO UNIT
DATA PLATE FOR VOLTAGE
3. ALL MOTORS ARE INHERENTLY
PROTECTED
4. USE 60° C WIRE
5. 115 VOLT CONTROL CIRCUIT
6. USE COPPER CONDUCTORS ONLY
FAN MOTOR IDENTIFICA TION
ELECTRIC BOX
3A-500V
END
HEADER
F7
GND
S
Figure 11, Twelve Fan, Two Row, ACD/AQD, Wiring with Cont act or s f o r Fi eld Installed Control
OPTION
P66
L1
GND
L3
L2
1
L
3PH/50/60HZ
T2 T3
T1
MAIN POWER CIRCUIT
TERMINAL
BOARD
DOOR
DISCONNECTSWITCH
L
O
R
T
N
L
R
E
O
E
B
C
D
A
L
E
L
R
O
O
U
H
)
R
T
S
T
E
O
S
R
N
S
T
E
E
E
U
C
R
F
R
F
M
A
E
P
O
T
E
T
O
R
N
E
(
C
T
O
L
A
O
T
S
M
C
L
C
N
E
Y
P
N
N
E
S
E
C
A
A
C
:
U
R
F
N
F
A
F
D
A
2
R
J
2
N
2
F
1
1
D
O
1
E
M
F
A
C
F
-
P
-
G
-
1
1
1
C
E
L
:
E
T
O
N
E
N
D
R
E
D
A
E
H
N
O
I
T
A
C
I
F
I
T
N
E
D
N
I
R
O
T
O
M
N
A
F
F
C
F
M
Y
L
E
N
G
O
Y
O
A
L
T
R
D
E
E
F
E
D
R
N
,
U
D
O
E
R
S
G
U
F
E
B
D
T
L
E
S
I
U
F
M
E
T
B
I
N
O
U
T
.
.
2
1
T
T
S
T
L
I
N
R
O
U
E
O
V
C
R
T
R
R
E
I
C
H
O
C
U
F
N
D
L
I
N
E
O
E
T
O
R
R
A
E
T
C
A
L
R
N
I
D
P
R
S
O
E
E
W
A
R
T
C
P
T
O
C
C
A
P
T
T
°
E
L
D
O
0
O
T
O
C
6
T
I
M
O
V
E
E
N
R
L
5
S
S
L
P
U
1
U
U
1
A
.
.
.
.
6
5
4
3
X
O
B
C
I
R
T
C
E
L
E
F7
3A-500V
NSFORMER
TRA
N
O
I
T
P
O
L
7
A
D
N
I
R
M
A
R
2
1
O
E
T
T
B
T
C2
L
A
N
I
M
R
E
T
R
T
460VOR250V
F5
F9
8
D
R
A
2
O
T
B
F1
A
N
S
F
O
R
E
M
R
24V
INPUT
F3
C5
L3
L2
L1
F6
F7
L3
L2
L1
F10
F11
L
9
A
D
N
I
R
M
A
1
R
O
T
E
B
T
C4
C1
L2
T2
T1
L1
L2
L1
C3
L3
T3
T2
L2
T1
L1
F4
T3
T2
T1
C6
L3
T3
L2
T2
L1
T1
F8
C9
T3
T2
T1
C10
L3
L2
L1
F12
2
1
T
T
C6
C4
L3
T3
T2
L2
L1
T1
L3
L2
M5
L1
L3
L2
L1
C7
L3
T3
L2
T2
L1
T1
C8
L3
T3
L2
T2
L1
T1
L3
L2
M9
L1
T3
T2
T1
L3
L2
L1
L3
L2
L1
C11
T3
T2
T1
C12
L3
T3
L2
T2
L1
T
L
0
1
A
N
D
I
R
M
A
1
2
R
O
T
T
E
B
T
C9
GND
GND
L1
GND
GND
P66
L3
L2
M3
L1
L3
L2
M4
L1
M6
L3
L2
M7
L1
L3
L2
M8
L1
M10
L3
L2
M11
L1
L3
L2
M12
L1
1
L
1
L
1
A
N
D
I
R
M
A
R
O
E
B
T
2
1
A
N
D
I
R
M
A
1
2
T
2
R
O
T
T
E
B
T
C10
L
C
I
O
R
R
D
T
M1
T
E
C
N
E
E
N
O
L
P
A
E
F
S
C
L2 R
L1 C
M1
ELECTRIC
FAN
L2 R
L1 C
1
T
C12
SPEED
MOTOR
M1
S
VARIABLE SPEED
CONTROL
CONTROL
M2
S
VARIABLE SPEED
CONTROL MOTOR
N
C1
L
1
A
2
D
N
I
T
R
M
A
R
O
E
B
FAN CONTROL CIRCUIT
1PH/50/60HZ
15 AMPS MAX
T
OVERCURRENT PROTECTIO
C3
L
2
A
2
1
D
N
I
T
T
R
M
A
R
O
E
B
T
C5
L
3
A
2
1
D
N
I
T
T
R
M
A
R
O
E
B
T
7
C
L
4
A
2
1
D
N
I
T
T
R
M
A
R
O
E
B
T
C8
L
5
A
1
2
D
N
T
T
I
R
M
A
R
O
E
B
T
C11
2
1
T
1
T
T
BOARD 6
TERMINAL
NAL BOARDS
TERMI
FOR FIELD CONTROL
OF FAN CONTACTOR
20 Air-cooled Condensers IOM ACAQ -1
Operation
Start-Up
Check for proper fan rotation. Air is drawn through the coil on all units. Be sure the fans
turn freely. Rotation of the motors and blades should be in a "clock-wise" direction looking
at the unit from the blade side. On three phase units, it may be necessary to reverse two of
the three power leads to the unit.
Discharge Gas Pulsation
Gas pulsations in a refrigeration system are most commonly associated with the compressor
and connecting discharge piping. Variations in the system piping configuration, line sizing,
operating pressures and compressor and component mounting all contribute to the presence
and magnitude of these pulsations. The vibration and movement of components caused by
the pulsations may result in line breakage or damage to the condenser. In order to eliminate
discharge pulsations and the potential for related condenser damage; install a discharge
muffler in the refrigeration piping. Follow the recommendations of the compressor or
muffler manufacturer when selecting these components.
Discharge Pressure Control
Proper application of controls is important to a successful installation. McQuay air-cooled
condensers have several options to meet the needs.
The capacity of an air-cooled condenser varies with the difference between the entering air
dry bulb temperature and the condensing temperature of the refrigerant. Since air
temperature varies from summer to winter, the condensing temperature must be kept high
enough to ensure proper operation of the refrigerant expansion valve during low ambient air
temperature operation, and also allow enough capacity so excessively high condensing
temperatures do not occur during high ambient conditions.
The low limit of the head pressure is dependent upon the required pressure drop across the
thermostatic expansion valve. For normal air conditioning applications, maintain head
pressure above a condensing temperature corresponding to 90°F. This corresponds to a
normal lower limit of about 60°F ambient air. When operation is required below 60°F
ambient air temperature, additional head pressure control will be required.
A decrease in ambient air temperature results in a capacity increase in the air-cooled
condenser. This capacity increase is directly proportional to the temperature difference
between the condensing temperature and the temperature of the ambient air entering the
condenser. Air-cooled condensers are often required to operate over a wide range of
ambient air temperatures and variable loading conditions so provisions must be made to
maintain the overall system balance. Low head pressures cause poor expansion valve
operation and poor system operation.
The cycling of condenser fans provides an automatic means of maintaining head pressure
control, within reasonable limits, at lower ambient air temperatures. A fan cycling control
system allows fans to cycle in sequence by sensing condensing pressures. Short cycling is
normally caused by too close a differential in the control settings or set points. If field
supplied flooding valves are used with fan cycling, set valves to follow the fan cycling. Set
pressure switches to at least 35 PSIG differential setting.
Any fan cycle that is less than three minutes is considered short cycling, and could be
detrimental to the system. Adjust controls accordingly.
Use optional SpeedTrol variable speed fan control for operation below 35°F ambient air
temperature
IOM ACAQ -1 Air-cooled Condensers 21
System A rrangement s:
The ACS and AQS models have one refrigerant circuit with a single row of two to six fans.
The ACD and AQD have two refrigerant circuits wi th two rows of fans. Their total fan
quantity is from four to twelve fans, split evenly between the rows. Each row serves a
separate refrigerant circuit. For larger capacity applications, the refrigerant circuits for
ACD and AQD models may be manifolds together to form a single refrigera nt circuit. The
manifolds can be field-fabricated and installed or purchased as an option and field installed.
For example, for a McQuay WGS-190A chiller, with two refrigerant circuits, it is
acceptable to use two separate ACD condensers. Because each ACD has two refrigerant
circuits, the two ACD circuits will need to be manifolded together to make a single circuit
on each condenser. In contrast, do not manifold two refrigeration circuits into a single
circuit in the condenser because oil management problems can occur.
The fan control arrangement is shown in Table 15 and Table 16 on page 25. Condenser
pressure control is provided by varying the total coil airflow by changing the number of
operating fans and/or the speed of the “first on, last off” fan. The number of control stages
is shown in the tables. The SpeedTrol option should be used when unit operation is
expected in ambient temperatures between 0°F and 35°F. When condenser circuits are
manifolded, the corresponding controls need to be coupled together.
Control options:
One of four control options will have been supplied on any unit. Other special options can
be offered to meet individual requirements.
1. Standard Control (Ordering Code = Y)
The standard unit is provided with a contactor for each fan motor. A customer-supplied,
and field-installed, control signal from another source is required to energize each contactor
and turn on the fan, based on the condenser pressure. Field wiring between the
compressorized product and the remote condenser is required. Refer to local codes for this
wiring. The contactor control voltage is 115 volts and a transformer is not provided.
Special options are available if the control signal is 24 or 230 volts.
Typical control logic is to start additional fans as condensing pressure increases. Although
the parameters of the companion refrigeration system dictates, it is good practice to only
use this option only for operation above ambient air temperatures of 35°F.
Setting: The setting of the controls will depend on the specific controls furnished. After
the controls are set, observe the operation of the unit under varying load and air
temperatures to check for proper operation.
2. Standard Control with Optional SpeedTrol (Orde ring Code = C)
This option is identical to the Standard Control (Code = Y) except the “first on, last off” fan
will have a variable speed drive. A control transformer is provided to power the variable
speed drive.
Condenser head pressure control is provided by varying the air flow through the condenser
by changing the speed of the first/last condenser fan. The fan motor next to the header end
of the condenser is the variable speed fan. The remainder of the fans are constant speed
and are cycled separately using field supplied controls. On condensers with two rows of
fans, two variable speed fans are provided (one per row) and the remainder of the fans are
constant speed.
Important: this option does not include a method of starting or cycling the balance of fans
on the condenser. Some means to do so must be supplied, mounted and wired in the field.
The MicroTech controller on McQuay WGZ or WGS chillers can provide this staging
function. The fan staging arrangement is shown in Table 15 for WGZ chillers and Table 16
for WGS chillers.
22 Air-cooled Condensers IOM ACAQ -1
Setting: SpeedTrol is performed by a Johnson Controls P66 Electronic Fan Speed Control
driving a single-phase fan motor. The control senses discharge pressure and varies the
voltage to the motor and hence its speed. Operation is in accordance with the following
table.
Table 12, P66 Operation
Pressure Input Motor Voltag e (VAC, True RMS )
Pressure is between 0 psig and the low end of the
operating range.
Pressure is at the low end of the operating range.
Pressure is in the operating range.
Pressure is above the operating range.
0 to 5 volts, motor off
Start voltage (10% to 40% of line volts, model
specific)
Motor voltage (and fan speed) varies directly with
pressure from the start voltage to 90% of line volts.
A further pressure increase of 20 to 30 psi will
increase motor voltage to 97% of the applied volts.
The setting of the P66 control must be coordinated with the settings of the field supplied
fan staging controls, so that the fan is the first fan to start and the last to shut off. To adjust
the operating range, locate the adjustment screw on the control’s transducer. The screw can
be accessed through the opening in the upper left-hand corner of the control’s base. Turn
the screw clockwise to increase, or counterclockwise to decrease, the operating range. One
turn equals approximately 35 psig of change.
A P66AAB-9 control is used for R-22. It has an operating (throttling) range of 170 to 230
psig. This 60 psi throttling range is not adjustable. The adjustment moves the entire range
up or down. For example, one screw turn clockwise will change the setting from 170/230
psig to 205/265 psig.
Figure 12, SpeedTrol Operating Range
97%
90%
e
g
a
t
l
o
V
r
o
t
o
M
No fan operation
in this
pressure range.
0
psig
Throttling
Range
Operating Range
(i.e., 190/250 psig)
Operating Range
Plus 20 or 30 psi*
*20 psi for 30 psi Effective Throttling Range (ETR)
30 psi for 60 psi Effective Throttling Range (ETR)
350 psig
Pressure Input
The setting of the speed control must be coordinated with pressures switch settings (or
MicroTech staging) so that the fan starts (at minimum speed) when the pressure switch
closes, starting the fan. As the discharge pressure increases, the fan speed will increase.
Additional fans may stage on and the control should float the # 1 fan speed up and down as
the fans stage on, avoiding sudden changes in discharge pressure that can upset unit
operation, especially expansion valve control. With the first fan on at 190 psig (see Table
14), set the fan control to start the motor at the same pressure, i.e, 190 psig.
IOM ACAQ -1 Air-cooled Condensers 23
Table 13, P66 Troubleshooting Chart
Problem Possible Causes Possible Solution
Input pressure is below operating range. No problem, normal operation.
No 24 volt control voltage. Check for 24 VAC at control.
No input pressure to control.
No fan operation
Bad fan motor
Pressure transducer problem
Fan stops when pressure
reaches the high end of
the operating range.
Fan starts at full speed
Erratic fan operation
Fan motor is cycling
thermal overload
Control is not wired correctly See wiring diagram
Control is not wired correctly See wiring diagram No fan modulation
Pressure transducer problem
Dirty or blocked condenser coil Clean condenser coil
Pressure Transducer Troubleshooting
1. Disconnect 6-pin connector from the right side of control.
Alignment. Schrader valve not
depressed sufficiently.
Disconnect power. Place a jumper
from L to M, and reconnect power.
If fan does not run, motor is bad
and should be replaced.
See Pressure Transducer
Troubleshooting following.
See Pressure Transducer
Troubleshooting following
2. Place a jumper wire between third pin from the top and the bottom pin on the control,
not the cable.
a. If the fan goes to full speed, check for input pressure
b. If there is adequate pressure, the transducer is bad and the control must be replaced.
3. Optional Pressure Switch Control with Control Transformer (Ordering Code = A)
This option provides direct control of discharge pressure through a series of factorymounted and wired pressure switches (designated as FCP-Fan Cycle Pressure Control-on
the wiring diagrams). As the condenser pressure increases, more pressure switches close
and start additional condenser fans. Field wiring between the compressorized product and
the remote condenser is not required. A control power transformer is included for 115 volt
power for the control voltage. Although the parameters of the refrigerant system dictates, it
is good practice to only use this option only for operation above ambient air temperatures of
35°F.
Setting: The fan pressure switches (FCP) are set per the following table. For example, a
setting of 190-140 means that the switch closes at 190 psig starting the fan and opens at 140
psig, shutting off the fan.
Table 14, Fan Pressure Switch Settings for R-22
Single-Row Fans
Fans FCP #1 FCP #2 FCP #3 FCP #4
1 x 2 190-140 230-170 - 1 x 3 190-140 220-160 230-170 1 x 4 190-140 210-150 220-160 230-170
1 x 5, 1 x 6 190-140 210-150 220-160 230-170
24 Air-cooled Condensers IOM ACAQ -1
Two-Row Fans
Fans FCP #1, FCP #2 FCP #3, FCP #4 FCP #5, FCP #6 FCP #7, FCP #8
2 x 2 190-140 230-170 - 2 x 3 190-140 220-160 230-170 2 x 4 190-140 210-150 220-160 230-170
2 x 5, 2 x 6 190-140 210-150 220-160 230-170
4. Optional Pressure Switch Control with Control Transformer & SpeedTrol (Code=B)
This option is identical to the pressure switch control system described above except with
the addition of variable speed control to the “first on, last off” fan for each circuit. The fan
pressure switches should be set per Table 14. The P66 fan speed controller is set as
explained in Section 2, above.
Standard Control (Code Y) or SpeedTrol (Code C) Using Chiller MicroTech Control Staging
The Standard Control (Code Y) or Standard Control with SpeedTrol (Code C) can utilize
the pressure sensing capability of a McQuay chiller’s MicroTech controller(s) to stage the
fans. The WGZ chiller has a single microprocessor with eight fan control digital outputs,
four for each refrigerant circuit. The WGS chiller has a separate controller for each of the
two circuits with six fan stages, for a total of twelve for the unit.
Field wiring is required between the chiller controller(s) and the fan contactors located in
the condenser. The number of connections will depend on the condenser size and
arrangement as show in the table below.
Table 15, WGZ Fan Staging and Field Wiring Circuits
Fan Stage
Fans
4
6
8
10
12
1 2 3 4 5 6 7 8
Circuit #1 Circuit#2
1 3 2 4 - 1 3 5 2 4 6
1 3 5 7 2 4 6 8
1 3 5 7, 9 2 4 6 8, 10
1 3 5, 7 9, 11 2 4 6, 8 10, 12
Table 16, WGS Fan Staging and Field Wiring Circuits
Fans
4
6
8
10
12
Circuit #1 Circuit#2
1 2 - - - - 1 2 - - - 1 2 3 - - - 1 2 3 - - 1 2 3 4 - - 1 2 3 4 - 1 2 3 4 5 - 1 2 3 4 5 1 2 3 4 5 6 1 2 3 4 5 6
Fan Stage
Fan Locations
12 10 8 6 4 2
Electric Panel
11 9 7 5 3 1
Circuit #2
Circuit #1
Electric Panel
IOM ACAQ -1 Air-cooled Condensers 25
6 5 4 3 2 1
Circuit #1
Maintenance
Air-cooled condensing units require a minimum of maintenance. The unit coil will require a
periodic cleaning. Clean the unit using a brush, vacuum cleaner, pressurized air stream or a
commercially available coil cleaning foam. All of the condenser fan motors have sealed
ball bearings and do not need maintenance. If bearings fail, then replace bearings.
Cleaning Instructions
Clean the finned surface at least every six months; more frequent cleaning may be required
if extreme conditions cause clogging or fouling of air passages through the finned surface.
Use Calgon Corporation's CalClean 41352 (or equal). Apply CalClean liberally to entering
air and leaving air surfaces of the finned area according to label directions and rinse
thoroughly to remove all cleaners.
CAUTION
Never clean this unit with an acid-based cleaner.
26 Air-cooled Condensers IOM ACAQ -1
This document contains the most current pr oduct information as of this printing. For the most up-todate product information, please go to www.mcquay.com.
Post Office Box 2510 Staunton, Virginia 24402-2510 USA • 540.248.0711 • www.mcquay.com IOM ACAQ-1 (1/05)
Loading...