McQuay AGS 251DP Installation Manual
Installation and Maintenance Manual
IMM AGSDP
Air-Cooled Screw Compressor Chillers
AGS 226DP through AGS 501DP
60 Hertz
R-134a
Group: Chiller
Part Number: 331375801
Date: November 2006
Supersedes: July 2006
Table Of Contents
Introduction ....................................... 3
General Description................................... 3
Nomenclature ............................................ 3
Inspection .................................................. 3
Installation and Start-up.....................4
Handling.................................................... 4
Location..................................................... 5
Service Access........................................... 5
Clearance Requirements............................ 6
Restricted Airflow ..................................... 7
Vibration Isolators................................... 13
Lifting and Mounting Weights................. 16
Chilled Water Pump ................................ 19
Water Piping............................................ 19
System Water Volume.............................. 20
Variable Speed Pumping ......................... 20
Evaporator Freeze Protection .................. 20
Operating Limits:..................................... 22
Flow Switch............................................. 22
Water Connections................................... 23
Refrigerant Charge .................................. 23
Glycol Solutions ...................................... 23
Water Flow and Pressure Drop........ 24
Solid State Starters...........................40
Component Location .......................48
Major Component Location..................... 48
Power Panel ............................................. 50
Control Panel ........................................... 51
Optional Features.............................52
Controls ................................................... 52
Electrical.................................................. 52
Unit.......................................................... 53
Start-up and Shutdown ....................54
Extended (Seasonal) Shutdown ............... 55
System Maintenance........................57
General .................................................... 57
Compressor Maintenance ........................ 57
Lubrication .............................................. 57
Electrical Terminals................................. 58
Condensers .............................................. 58
Liquid Line Sight Glass ........................... 58
Evaporator Sight Glass ............................ 59
Lead-Lag.................................................. 59
Preventative Maintenance Schedule ........ 60
Physical Data................................... 26
Dimensional Data ............................ 28
Wind Baffles and Hail Guards......... 30
BAS/Remote Panel Interface........... 32
BAS Interface.......................................... 32
Electrical Data ................................. 33
Field Wiring ............................................ 33
Field Wiring Diagram...................... 39
Warranty Statement.......................... 60
Service .............................................61
Liquid Line Filter-Driers.......................... 61
Compressor Slide Valves ......................... 62
Electronic Expansion Valve..................... 62
Evaporator ............................................... 63
Charging Refrigerant ............................... 63
Charging Oil ............................................ 66
Standard Controls .................................... 66
Controls, Settings and Functions ............. 71
Troubleshooting Chart ............................. 72
Periodic Maintenance Log ....................... 73
Unit controllers are LONMARK certified
with the optional LONWORKS
communications module.
Manufactured in an ISO Certified facility
Information covers the McQuay International products at the time of publication and we reserve the right
to make changes in design and construction at anytime without notice.
The following are trademarks or registered trademarks of their respective companies: BACnet from ASHRAE; LonTalk from Echelon Corporation;
Modbus from Schneider Electric Ltd.; Open Choices from McQuay International.
2 IMM AGS-DP
Introduction
General Description
McQuay AGS-DP air-cooled water chillers are complete, self-contained, automatic
refrigerating units that include the latest in engineered components, arranged to provide a
compact and highly efficient unit. Each unit is completely assembled, factory wired,
evacuated, charged, tested and comes complete and ready for installation. Each unit consists
of multiple air-cooled condenser sections with an integral subcooler section. Each condenser
circuit has a semi-hermetic single-screw compressor, solid-state starter, a multiple-circuit shelland-tube flooded evaporator, and complete refrigerant piping. Each compressor has an
independent refrigeration circuit. Liquid line components included are manual liquid line
shutoff valves, charging ports, filter-driers, sight-glass/moisture indicators, and electronic
expansion valves. A discharge check valve is included and a compressor suction shutoff valve
is optional. Other features include compressor heaters, evaporator head heaters, automatic
one-time pumpdown of refrigerant circuit upon circuit shutdown, and an advanced fully
integrated microprocessor control system.
Information on the operation of the unit and on the MicroTech II controller are in the OM
AGS-DP manual. Installation and operating instructions will be shipped with the unit if a
LONT
ALK
, Modbus or BACnet BAS interface is ordered.
Nomenclature
A G S - XXX D P
Rotary Screw Compressor
Air-Cooled
Global
Premium
Efficiency
Design Vintage
Model Number
(Nominal Tons)
Inspection
When the equipment is received, check all items carefully against the bill of lading to check
for a complete shipment. Carefully inspect for damage upon arrival. Report shipping damage
to the carrier and file a claim 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.
Note: Unit shipping and operating weights are shown in the Physical Data Tables on page 26.
IMM AGS-DP 3
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.
Start-up by McQuay Factory Service is included on all units sold for installation within the
USA and Canada and must be performed by them to initiate the standard limited product
warranty. Two-week prior notification of start-up is required. The contractor should obtain a
copy of the Start-up Scheduled Request Form from the McQuay sales representative or from
the nearest office of McQuay Factory Service.
Handling
Avoid rough handling or 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.
To lift the unit, lifting tabs with 2½" (64 mm) diameter holes are provided on the base of the
unit. All lifting holes must be used when lifting the unit. Arrange spreader bars and cables to
prevent damage to the condenser coils or unit cabinet (see Figure 1).
WARNING
Avoid contact with them.
Improper lifting or moving unit can result in property damage, severe
personal injury or death. Follow rigging and moving instructions carefully.
NOTES:
1. All rigging points on a unit must
be used. See page 16 for
location, and weight at lifting
points for a specific size unit.
2. Crosswise and lengthwise
spreader bars must be used to
avoid damage to unit. Lifting
cables from the unit mounting
holes up must be vertical.
3. The number of lifting points,
condenser sections, and fans
can vary from this diagram.
DANGER
Figure 1, Required Lifting Method
4 IMM AGS-DP
Location
Locate the unit to provide proper airflow to the condenser. (See Figure 2 on page 6 for
required clearances).
Due to the shape of the condenser coils on the AGS-DP chillers, it is desirable to orient the
unit so that prevailing winds blow parallel to the unit length, thus minimizing the wind effect
on condensing pressure and performance. If low ambient temperature operation is expected, it
is recommended that optional wind baffles or louvers be factory or field installed if the unit
has no protection against prevailing winds.
Using less clearance than shown in Figure 2 can cause discharge air recirculation to the
condenser and could have a significant detrimental effect on unit performance.
See Restricted Airflow beginning on page 7 for further information.
For pad-mounted units, it is recommended that the unit be raised a few inches with suitable
supports, located at least under the mounting locations, to allow water to drain from under the
unit and to facilitate cleaning under it.
Service Access
Compressors, filter-driers, and manual liquid line shutoff valves are accessible on each side of
the unit adjacent to the control box. The evaporator heaters are located in each head.
Each compressor (two or three depending on unit size) has its own duplex control panel
located on the sides of the chiller between condenser coil sections. A control panel is to the
left of the condenser and compressor it controls. The outer control box contains the circuit
microprocessor. The box for circuit #1 also contains the unit microprocessor controller. The
solid state compressor starter, fan control and other power equipment are located in the inner
panel.
The side clearance required for airflow provides sufficient service clearance.
On all AGS units the condenser fans and motors can be removed from the top of the unit. The
complete fan/motor assembly can be removed for service. The fan 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 or compressors.
Failure to do so can 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 panels with a field-mounted
disconnect switches. In particular, be sure that the power conduit to each panel does not
interfere with access to the filter-driers located on the unit base under the panels.
IMM AGS-DP 5
Clearance Requirements
5’-0” if open fence or 50% open wall
6’-0” if solid wall (see note 3 for pit)
6’-0” if solid wall (see note 3 for pit)
10’-0” min. for
Evaporator Removal
Air Flow
No obstructions allowed
above unit at any height
Figure 2, Clearance Requirements, AGS 226DP – 501DP
No obstructions.
Recommended area
required for unit
operation, air flow
and maintenance
access.
5’-0” if open fence or 50% open wall
See notes 2 & 4
concerning wall
height at unit sides.
See Note 8
See Note 5
Wall or
Fence
Notes:
1. Minimum side clearance between two units is 12 feet (3.7 meters).
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 (2.4 meters) when installed in a pit no deeper than the unit
height.
4. Minimum side clearance to a side wall or building taller than the unit height is 6 feet (1.8 meters),
provided no solid wall above 6 feet (1.8 meters) is closer than 12 feet (3.7 meters) to the opposite
side of the unit.
5. Do not mount electrical conduits where they can block service access to compressor controls,
refrigerant driers or valves.
6. There must be no obstruction of the fan discharge.
7. Field installed switches must not interfere with service access or airflow.
8. The 10-ft. clearance required for removal of the evaporator is on the end that the evaporator
connections face. See dimension drawings on page 28 for details.
9. See the following pages if the airflow clearances cannot be met.
6 IMM AGS-DP
Restricted Airflow
General
The clearances required for design operation of AGS air-cooled condensers are described in
the previous section. Occasionally, these clearances cannot be maintained due to site
restrictions such as units being too close together or a fence or wall restricting airflow, or both.
The McQuay AGS chillers have several features that can mitigate the problems attributable to
restricted airflow.
• The “W” shape of the condenser section allows inlet air for these coils to come in from
both sides and the bottom. All the coils in one "W" section serve one compressor. Every
compressor always has its own independent refrigerant circuit.
• The MicroTech II control is proactive in response to off-design conditions. In the case
of single or compounded influences restricting airflow to the unit, the microprocessor will
act to keep the compressor(s) running (at reduced capacity) as long as possible, rather than
allowing a shut-off on high discharge pressure.
Figure 3, Coil and Fan Arrangement
The following sections discuss the most common situations of condenser air restriction and
give capacity and power adjustment factors for each. Note that in unusually severe conditions,
the MicroTech II controller would adjust the unit operation to remain online until a less severe
condition is reached.
IMM AGS-DP 7
Case 1, Building or Wall on One Side of One Unit
5 ft.
(1.5m)
(1.8m)
The existence of a screening wall, or the wall of a building, in close proximity to an air-cooled
chiller is common in both rooftop and ground level applications. Hot air recirculation on the
coils adjoining the wall will increase compressor discharge pressure, decreasing capacity and
increasing power consumption.
When close to a wall, it is desirable to place chillers on the north or east side of them. It is
also desirable to have prevailing winds blowing parallel to the unit’s long axis. The worst case
is to have wind blowing hot discharge air into the wall.
Figure 4, Unit Adjacent to Wall
D
H
Figure 5, Adjustment Factors
(1.5m)
6 ft.
(1.8m)
5 ft.
6 ft.
8 IMM AGS-DP
Case 2, Two Units Side By Side
Two or more units sited side by side are common. If spaced closer than 12 feet (3.7 meters) it
is necessary to adjust the performance of each unit; circuits adjoining each other are affected.
If one of the two units also has a wall adjoining it, see Case 1. Add the two adjustment factors
together and apply to the unit located between the wall and the other unit.
Mounting units end to end will not necessitate adjusting performance. Depending on the
actual arrangement, sufficient space must be left between the units for access to the control
panel door opening and/or evaporator tube removal. See “Clearance” section of this guide for
requirements for specific units.
Pit or solid wall surrounds should not be used where the ambient air temperature exceeds
105°F (40°C).
Figure 6, Two Units Side by Side
Figure 7, Adjustment Factor
IMM AGS-DP 9
Case 3, Three or More Units Side By Side
When three or more units are side by side, the outside units (chillers 1 and 3 in this case) are
influenced by the middle unit only on their inside circuits. Their adjustment factors will be
the same as Case 2. All inside units (only chiller 2 in this case) are influenced on both sides
and must be adjusted by the factors shown below.
Figure 8, Three or More Units
Chiller 1 Chiller 2 Chiller 3
Figure 9, Adjustment Factor
4.0
3.0
2.0
1.0
0
15
(4.6)
16
(4.9)
17
(5.2)
18
(5.5)
8.0
6.0
4.0
2.0
0
15
(4.6)
16
(4.9)
17
(5.2)
18
(5.5)
10 IMM AGS-DP
Case 3, Open Screening Walls
Decorative screening walls are often used to help conceal a unit either on grade or on a
rooftop. These walls should be designed such that the combination of their open area and
distance from the unit do not require performance adjustment. It is assumed that the wall
height is equal to, or less than the unit height when mounted on its base support. This is
usually satisfactory for concealment. If the wall height is greater than the unit height, see Case
4, Pit Installation.
The distance from the sides of the unit to the side walls should be sufficient for service and
opening control panel doors.
If each side wall is a different distance from the unit, the distances can be averaged, providing
either wall is not less than 8 feet (2.4 meters) from the unit. For example, do not average 4 feet
and 20 feet to equal 12 feet.
Figure 10, Open Screening Walls
Figure 11, Wall Free Area vs. Distance
IMM AGS-DP 11
Case 4, Pit/Solid Wall Installation
Pit installations can cause operating problems and great care should be exercised if they are to
be used on an installation. Recirculation and restriction can both occur. A solid wall
surrounding a unit is substantially the same as a pit and the data presented in this case should
be used.
Steel grating is sometimes used to cover a pit to prevent accidental falls or trips into the pit.
The grating material and installation design must be strong enough to prevent such accidents,
yet provide abundant open area or serious recirculation problems will occur. Have any pit
installation reviewed by McQuay application engineers prior to installation to discuss whether
it has sufficient airflow characteristics. The installation design engineer must approve the
work and is responsible for design criteria.
Figure 12, Pit Installation
Figure 13, Adjustment Factor
12 IMM AGS-DP
Vibration Isolators
Max. L oad
Vibration isolators are recommended for all roof-mounted installations or wherever vibration
transmission is a consideration. The following section "Lifting and Mounting Weights"
contains the location of unit lifting holes and the load at each location. Mounting holes
dimensions and the bearing weight at each hole are also given.
Table 1, Spring Flex Isolator Data
9.0
(228. 6)
9.0
(228. 6)
9.0
(228. 6)
9.0
(228. 6)
5.0
(127. 0)
5.0
(127. 0)
5.0
(127. 0)
Dimensions
In. (m m)
7.7
(195. 6)
7.7
(195. 6)
7.7
(195. 6)
7.7
(195. 6)
Dimensions
In. (m m)
0.56
(14.2)
0.56
(14.2)
0.56
(14.2)
2.7
(68.6)
2.7
(68.6)
2.7
(68.6)
2.7
(68.6)
0.25
(6.4)
0.25
(6.4)
0.25
(6.4)
5.75
(146. 0)
5.75
(146. 0)
5.75
(146. 0)
5.75
(146. 0)
1.6
(41.1)
1.6
(41.1)
1.6
(41.1)
Housing
Part
Number
226103B -00 (2) 226117A-00
226103B -00 (2) 226118A-00
226103B -00 (2) 226119A-00
226103B -00 (2) 226120A-00
6.5
(165. 1)
6.5
(165. 1)
6.5
(165. 1)
4.6
(116. 8)
4.6
(116. 8)
4.6
(116. 8)
Housing
CP-2-27 Orange
CP-2-28 Green
CP-2-31 Gray
CP-2-32 White
Spring
Color
Max. L oad
Each
Lbs. (kg)
1500
(681)
1800
(815)
2200
(998)
2600
(1180 )
Def l.
In. (m m)
0.5
(12.7)
0.5
(12.7)
0.5
(12.7)
0.5
(12.7)
A B C D E
10.2
(259. 1)
10.2
(259. 1)
10.2
(259. 1)
10.2
(259. 1)
Table 2, Neoprene-in-Shear Isolator Data
Type
RP-4 B lack
RP-4 Red
RP-4 Green
Note (1) "D" is the m ounting hole diam eter.
Each
Lbs. (kg)
1500
(681)
2250
(1019 )
3300
(1497 )
Def l.
In. (m m)
0.25
(6.4)
0.25
(6.4)
0.25
(6.4)
A B C D (1) E H L W
3.75
(95.3)
3.75
(95.3)
3.75
(95.3)
0.5
(12.7)
0.5
(12.7)
0.5
(12.7)
Spring
Part Number
McQuay
Part
Number
216398A -04
216398A -01
216398A -03
Figure 14, Spring Flex Mountings, CP-2 Figure 15, Neoprene-in-Shear
Mounting, RP-4
IMM AGS-DP 13
Table 3, Spring Vibration Isolators, AGS 226DP–301DP, Part Numbers and Spring Colors
Model
AGS 226DP
AGS 251DP
AGS 276DP
AGS 301DP
Notes:
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
2. The -2- or -4- indicates that two or four springs are used in the isolator.
M1 M2 M3 M4 M5 M6 M7 M8 Kit Number
CP-2-28 CP-2-31 CP-2-28 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Green Gray Green Gray Gray Green Gray Green
CP-2-28 CP-2-31 CP-2-28 CP-2-31 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Gray Green Gray White Gray Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-2-32 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Purple Gray White White Gray Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-2-32 CP-2-32 CP-2-31 CP-4-26 CP-2-28
Green Purple Gray White White Gray Purple Green
Mounti ng Location , See Foo tp ri nt Drawin gs Figure 16 or Figu re 17
Table 4, Spring Vibration Isolators, AGS 351DP–501DP, Part Numbers and Spring Colors
Model
AGS 351DP
AGS 391DP
AGS 401DP
AGS 451DP
AGS 501DP
Model
AGS 351DP
AGS 391DP
AGS 401DP
AGS 451DP
AGS 501DP
Notes:
1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
2. The -2- or -4- indicates that two or four springs are used in the isolator.
Mounti ng Location , See Foo tp ri nt Drawin gs Figure 18, Figure 19
M1 M2 M3 M4 M5 M6
CP-2-28 CP-4-26 CP-2-28 CP-4-26 CP-4-26 CP-2-28
Green Purple Green Purple Purple Green
CP-2-28 CP-4-26 CP-2-31 CP-4-26 CP-4-27 CP-2-31
Green Purple Gray Purple Orange Gray
CP-2-31 CP-4-26 CP-2-31 CP-4-27 CP-4-27 CP-2-31
Gray Purple Gray Orange Orange Gray
CP-2-31 CP-4-26 CP-4-26 CP-4-27 CP-4-27 CP-4-26
Gray Purple Purple Orange Orange Purple
CP-2-31 CP-4-26 CP-4-26 CP-4-27 CP-4-27 CP-4-26
Gray Purple Purple Orange Orange Purple
Mounting Location (Table Continued)
M7 M8 M9 M10 M11 M12 Kit Number
CP-4-26 CP-2-28 CP-2-31 CP-2-27 CP-2-27 CP-2-27
Purple Green Gray Orange Orange Orange
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
CP-4-26 CP-2-31 CP-2-31 CP-2-28 CP-2-31 CP-2-28
Purple Gray Gray Green Gray Green
350348101
350348102
350348103
Continued
350348104
350348106
350348107
350348108
14 IMM AGS-DP
Table 5, Neoprene-in-Shear Isolators, AGS 226 – 301, RP Part Numbers
Model
AGS 226DP
AGS 251DP
AGS 276DP
AGS 301DP
Note: The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
M1 M2 M3 M4 M5 M6 M7 M8 Kit Number
4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 350348201
4-RED 4-RED 4-RED 4-RED 4-GREEN 4-RED 4-RED 4-RED 350348202
4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED
4-RED 4-RED 4-RED 4-GREEN 4-GREEN 4-RED 4-RED 4-RED
Mounti ng Location , See Foo tp ri nt Drawin gs Figure 16 or Figu re 17
Table 6, Neoprene-in-Shear Isolators, AGS 351 – 501, RP Part Numbers
Model
AGS 351DP
AGS 391DP
AGS 401DP
AGS 451DP
AGS 501DP
Model
AGS 351DP
AGS 391DP
AGS 401DP
AGS 451DP
AGS 501DP
Note: The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.
Mounti ng Location , See Foo tp ri nt Drawin gs Figure 18, Figure 19
M1 M2 M3 M4 M5 M6
4-RED 4-RED 4-RED 4-RED 4-RED
4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED
4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED
4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED
4-RED 4-GREEN 4-RED 4-GREEN 4-GREEN 4-RED
4-RED
Mounting Location (Table Continued)
M7 M8 M9 M10 M11 M12 Kit Number
4-RED 4-RED 4-RED 4-RED 4-RED 4-RED 350348204
4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED
4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED
4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED
4-GREEN 4-RED 4-RED 4-RED 4-RED 4-RED
350348205
The unit should be initially installed on shims or blocks at the illustrated "free height"
of the isolator that is six inches for the McQuay isolators shown. When all piping,
wiring, flushing, charging, etc. is complete, the springs should be adjusted upward to
load them and to provide clearance to free the blocks, which are then removed.
350348203
Installation of spring isolators requires flexible pipe connections and at least three feet
of conduit flex tie-ins. Piping and conduit should be supported independently from the
unit so as not to stress connections.
IMM AGS-DP 15
Lifting and Mounting Weights
AGS226
AGS251
2 (51)
Typical Spacing
Figure 16, AGS 226DP – AGS 251DP Lifting and Mounting Locations
AGS226
AGS251
AGS226
AGS226
AGS251
AGS251
Figure 17, AGS 276DP - AGS 301DP Lifting and Mounting Locations
Table 7, AGS 226DP - AGS 301DP Lifting and Mounting Weights (Aluminum Fin)
AGS
Model
226DP
251DP
276DP
301DP
NOTES:
1. Lifting tabs with 2½ in. (63.5 mm) holes at location "L" on side of base rail.
2. 1 in. (25.4 mm) mounting holes at location "M" on bottom of base rails.
Lifting Weigh t fo r Each Po int lb (k g) Mounting Loads for Each Point lb. (kg )
L1 L 2 L3 L4 L5 L6 M1 M2 M3 M4 M 5 M6 M7 M 8
Lbs. 2183 3043 2563 2563 3043 2183 1683 2325 1681 2322 2322 1681 2325 1683
(kg) 991 1382 1164 1164 1382 991 764 1055 763 1054 1054 763 1055 764
Lbs. 2183 3043 2700 2704 3374 2509 1683 2325 1681 2322 2693 2018 2421 1814
(kg) 991 1382 1226 1228 1532 1139 764 1055 763 1054 1223 916 1099 824
Lbs. 2509 3374 2841 2841 3374 2509 1814 2421 2018 2693 2693 2018 2421 1814
(kg) 1139 1532 1290 1290 1532 1139 824 1099 916 1223 1223 916 1099 824
Lbs. 2550 3407 2956 2956 3407 2550 1838 2435 2111 2797 2797 2111 2435 1838
(kg) 1158 1547 1342 1342 1547 1158 834 1106 958 1270 1270 958 1106 834
for Isolator
Mounting (8)
88.0
(2235.2)
16 IMM AGS-DP
Table 8, AGS 226DP - AGS 301DP Lifting and Mounting Weights (Copper Fin)
2 (51)
Typical Spacing
391
2 (51)
Typical Spacing
AGS
Model
226DP
251DP
276DP
301DP
Lbs. 2499 3359 2879 2879 3359 2499 1920 2562 1918 2559 2559 1918 2562 1920
(kg) 1135 1525 1307 1307 1525 1135 872 1163 871 1162 1162 871 1163 872
Lbs. 2552 3412 3069 3073 3743 2878 1960 2602 1958 2599 2970 2295 2698 2091
(kg) 1158 1549 1393 1395 1699 1306 890 1181 889 1180 1348 1042 1225 949
Lbs. 2930 3795 3262 3262 3795 2930 2130 2737 2334 3009 3009 2334 2737 2130
(kg) 1330 1723 1481 1481 1723 1330 967 1243 1060 1366 1366 1060 1243 967
Lbs. 2971 3828 3377 3377 3828 2971 2154 2751 2427 3113 3113 2427 2751 2154
(kg) 1349 1738 1533 1533 1738 1349 978 1249 1102 1413 1413 1102 1249 978
NOTES:
1. Lifting tabs with 2½ in. (63.5 mm) holes at location "L" on side of base rail.
2. 1 in. (25.4 mm) mounting holes at location "M" on bottom of base rails.
Lifting Weight for Each Point lb (kg) Mounting Loads for Each Point lb. (kg)
L1 L2 L3 L4 L5 L6 M1 M2 M3 M4 M5 M6 M7 M8
Figure 18, AGS 351Dp – AGS 391DP Lifting and Mounting Locations
AGS351
AGS391
AGS351
AGS351
AGS351
391
88.0
(2235.2)
AGS351
AGS351
391
Figure 19, AGS 401DP - AGS 501DP Lifting and Mounting Locations
for Isolator
Mounting (8)
for Isolator
Mounting (8)
88.0
(2235.2)
IMM AGS-DP 17
Table 9, AGS 351DP- AGS 501DP Lifting Weights (Aluminum Fin)
Model
351DP
391DP
401DP
451Dp
501DP
AGS
L1 L2 L3 L4 L5 L6 L7 L8
lbs 2312 3173 2681 2681 3352 2473 3192 2880
(kg) 1050 1441 1217 1217 1522 1123 1449 1307
lbs 2449 3296 3119 3117 3917 3044 3519 3216
(kg) 1112 1496 1416 1415 1778 1382 1597 1460
lbs 2751 3596 3285 3285 3917 3044 3519 3216
(kg) 1249 1633 1491 1491 1778 1382 1597 1460
lbs 2783 3624 3361 3361 3945 3076 3519 3216
(kg) 1263 1645 1526 1526 1791 1396 1597 1460
lbs 2783 3624 3361 3361 3945 3076 3519 3216
(kg) 1263 1645 1526 1526 1791 1396 1597 1460
Lifting Weight for Each Point lb. (kg)
Table 10, AGS 351DP- AGS 501DP Lifting Weights (Copper Fin)
Model
351DP
391DP
401DP
451Dp
501DP
AGS
L1 L2 L3 L4 L5 L6 L7 L8
lbs 2668 3529 3037 3037 3708 2829 3548 3236
(kg) 1211 1602 1379 1379 1683 1284 1611 1469
lbs 2884 3731 3554 3552 4352 3479 3954 3651
(kg) 1309 1694 1613 1612 1976 1579 1795 1657
lbs 3225 4070 3759 3759 4391 3518 3993 3690
(kg) 1464 1848 1707 1707 1994 1597 1813 1675
lbs 3257 4098 3835 3835 4419 3550 3993 3690
(kg) 1479 1860 1741 1741 2006 1612 1813 1675
lbs 3257 4098 3835 3835 4419 3550 3993 3690
(kg) 1479 1860 1741 1741 2006 1612 1813 1675
Lifting Weight for Each Point lb. (kg)
Table 11, AGS 351DP- AGS 501DP Mounting Weights (Aluminum Fin)
Mounting Loads for Each Point lb. (kg)
351DP
391DP
401DP
451Dp
501DP
AGS
Model
lbs 1798 2442 1787 2426 2426 1787 2442 1798 1726 1557 1645 1484
lbs 1885 2511 1981 2638 3055 2357 2562 1977 1973 1803 1867 1706
lbs 1977 2562 2357 3055 3055 2357 2562 1977 1973 1803 1867 1706
lbs 1999 2579 2425 3128 3128 2425 2579 1999 1973 1803 1867 1706
lbs 1999 2579 2425 3128 3128 2425 2579 1999 1973 1803 1867 1706
M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12
kg 816 1109 811 1101 1101 811 1109 816 784 707 747 674
kg 856 1140 899 1198 1387 1070 1163 897 896 819 847 775
kg 897 1163 1070 1387 1387 1070 1163 897 896 819 847 775
kg 908 1171 1101 1420 1420 1101 1171 908 896 819 847 775
kg 908 1171 1101 1420 1420 1101 1171 908 896 819 847 775
Table 12, AGS 351DP- AGS 501DP Mounting Weights (Copper Fin)
AGS
Model
351DP
391DP
401DP
451Dp
501DP
M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12
lbs 2035 2679 2024 2663 2663 2024 2679 2035 1963 1794 1882 1721
kg 924 1216 919 1209 1209 919 1216 924 891 814 854 781
lbs 2175 2801 2271 2928 3345 2647 2852 2267 2263 2093 2157 1996
kg 987 1272 1031 1329 1518 1202 1295 1029 1027 950 979 906
lbs 2293 2878 2673 3371 3371 2673 2878 2293 2289 2119 2183 2022
kg 1041 1307 1214 1530 1530 1214 1307 1041 1039 962 991 918
lbs 2315 2895 2741 3444 3444 2741 2895 2315 2289 2119 2183 2022
kg 1051 1314 1244 1564 1564 1244 1314 1051 1039 962 991 918
lbs 2315 2895 2741 3444 3444 2741 2895 2315 2289 2119 2183 2022
kg 1051 1314 1244 1564 1564 1244 1314 1051 1039 962 991 918
Mounting Loads for Each Point lb. (kg)
18 IMM AGS-DP
Chilled Water Pump
It is required that the starter(s) for the chilled water pump be wired to and controlled by the
chiller's microprocessor. The controller will energize the pump whenever at least one circuit
on the chiller is enabled to run, whether there is a call for cooling or not. The pump will also
be energized when the controller senses a near-freezing temperature at the chiller outlet sensor
to assist in freeze protection. Connection points are shown in Figure 27 on page 39.
Drain Valves at Initial Start-up
The evaporator water side is pressurized and drained in the factory and shipped with open
drain valves in each head. Be sure to close these valves before filling the vessel with fluid.
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.
NOTE
rail and the bottom of the condenser coil in the approximately 30-inch width shown on
Figure 23 and Figure 24.
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 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 and drains at the low
4. Some means of maintaining adequate system water pressure (i.e., expansion tank or
5. Water temperature and pressure indicators located at the unit to aid in unit servicing.
6. A strainer to remove foreign matter from the water before it enters the pump. The strainer
: Chilled water piping must enter and exit the unit platform between the base
parts in the system. If the evaporator is the highest point in the piping system, it must be
equipped with an air vent.
regulating valve).
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.
NOTE: A 20-mesh 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 or flanges to the evaporator connections to prevent any weld slag from
entering the vessel.
7. Protected water piping to the unit to prevent freeze-up if below freezing temperatures are
expected. See page 20 for further information on freeze protection.
CAUTION
If a separate disconnect is used for the 115V supply to the unit, it should
power the entire control circuit, not just the evaporator heaters. It should be
clearly marked so that it is not accidentally shut off during cold seasons.
Freeze damage to the evaporator could result. If the evaporator is drained
for winter freeze protection, the heaters must be de-energized to prevent
heater burnout.
IMM AGS-DP 19
8. If the unit is used as a replacement chiller on a previously existing piping system, flush the
system thoroughly prior to unit installation. Then regular chilled water analysis and
chemical water treatment is recommended at equipment start-up.
9. In the event glycol is added to the water system as a late addition 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.
10. For ice making or low temperature glycol operation, the freezestat pressure value will need
to be checked and probably lowered. The freezestat setting can be manually changed
through the MicroTech II controller.
Make a preliminary leak check prior to insulating the water piping and filling the system.
Include a vapor barrier on piping insulation to prevent moisture condensation and possible
damage to the building structure. It is important to have the vapor barrier on the outside of the
insulation to prevent condensation within the insulation on the cold surface of the pipe.
System Water Volume
It is important to have adequate water volume in the system to provide an opportunity for the 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 two to three minutes times the flow rate (gpm). For
example, if the design chiller flow rate is 600 gpm, we recommend a minimum system volume
of 1200 to 1800 gallons (600 gpm x 2 to 3 minutes).
Variable Speed Pumping
Variable 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 maximum change in water flow is 10 percent of the change per minute.
The water flow through the vessel must remain between the minimum and maximum values
listed on page 25. 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.
Evaporator Freeze Protection
Flooded evaporators are popular with chiller manufacturers because of their inherent high
efficiency. Care must be exercised in the equipment design and in the operation of these
evaporators to prevent freezing between 32°F and -20°F.
For protection down to 0°F (-18°C), the AGS chillers are equipped with thermostatically
controlled evaporator heaters that help protect against freeze-up provided the chiller goes
through its normal pumpdown cycle. Several occurrences can prevent this normal pumpdown
from happening:
20 IMM AGS-DP
1. A power failure will prevent pumpdown and there is a potential for freezing outdoor
equipment in systems using 100 percent water as the chilled fluid.
2. Unit shutdown due to a fault will cause immediate compressor shutdown without the
pumpdown cycle. This situation can be remedied by correcting the fault, restarting the
unit, and allowing it to go through its normal shutdown pumpdown.
NOTE: The heaters come from the factory connected to the control power circuit. If desired, the
3 KVA control transformer can be unwired and a field 115-volt power source wired to terminals
TB1-1 and TB1-2 in the control panel for circuit #1 (do not wire directly to the heater). If this is
done, the disconnect switch should be clearly marked to avoid accidental deactivation of the
heater during freezing temperatures. Exposed chilled water piping also requires protection.
CAUTION
It is required that the chilled water pump’s starter be wired to, and controlled by, the chiller's
microprocessor year around to avoid severe or terminal damage to the evaporator.
The controller will energize the pump whenever at least one circuit on the chiller is enabled to
run, whether there is a call for cooling or not. The pump will also be energized when the
controller senses a near-freezing temperature at the chiller outlet sensor to assist in cold
weather freeze protection. Connection points are shown in Figure 27 on page 39.
For additional protection to -20°F (-29°C) and to protect against the consequences described
above, it is recommended that at least one of the following procedures be used during periods
of sub-freezing temperatures:
1.
Addition of a concentration of a glycol anti-freeze with a freeze point 10 degrees F
(5.5 degrees C) below the lowest expected temperature. This will result in decreased
capacity and increased pressure drop. Note: Do not use automotive grade antifreezes as
they contain inhibitors harmful to chilled water systems. Only use glycols specifically
designated for use in building cooling systems.
2.
Draining the water from outdoor equipment and piping and blowing the chiller tubes dry
from the chiller. Do not energize the chiller heater when water is drained from the vessel.
CAUTION
If fluid is absent from the evaporator, the evaporator heater must be de-energized
to avoid burning out the heater and causing damage from the high temperatures.
3. Providing operation of the chilled water pump, circulating water through the chilled water
system and through the evaporator. The chiller microprocessor will automatically start up
the pump if so wired.
Table 13, Freeze Protection
Temperature
°°°°F (°°°°C)
20 (6.7) 16 18 11 12
10 (-12.2) 25 29 17 20
0 (-17.8) 33 36 22 24
-10 (-23.3) 39 42 26 28
-20 (-28.9) 44 46 30 30
-30 (-34.4) 48 50 30 33
-40 (-40.0) 52 54 30 35
-50 (-45.6) 56 57 30 35
-60 (-51.1) 60 60 30 35
Notes are on following page.
Ethylene Glycol Propylene Glycol Ethylene Glycol Propylene Glycol
For Freeze Protection For Burst Protection
Percent Volume Glycol Concentration Required
IMM AGS-DP 21
1. These figures are examples only and cannot be appropriate to every situation. Generally, for an extended margin
of protection, select a temperature at least 10°F lower than the expected lowest ambient temperature. Inhibitor
levels should be adjusted for solutions less than 25% glycol.
2. Glycol of less than 25% concentration is not recommended because of the potential for bacterial growth and
subsequent loss of heat transfer efficiency, or add inhibitors.
Operating Limits:
Maximum standby ambient temperature, 130°F (55°C)
Maximum operating ambient temperature, 115°F (46°C), or 125°F (52°C) with optional high
ambient package
Minimum operating ambient temperature (standard), 35°F (2°C)
Minimum operating ambient temperature (optional low-ambient control), 0°F (-18°C)
Leaving chilled water temperature, 40°F to 50°F (4.4°C to 10°C)
Leaving chilled fluid temperature (with anti-freeze), 20°F to 50°F (7°C to 10°C)
Operating Delta-T range, 6 degrees F to 16 degrees F (3.3 C to 8.8 C)
Maximum operating inlet fluid temperature, 66°F (19°C)
Maximum startup inlet fluid temperature, 90°F (32°C)
Maximum non-operating inlet fluid temperature, 100°F (38°C)
NOTE: Contact the local McQuay sales office for operation outside of these limits.
Flow Switch
A water flow switch must be mounted in the leaving chilled water line to prove that there is
adequate water flow to the evaporator before the unit can start. It also serves to shut down the
unit in the event that water flow is interrupted in order to guard against evaporator freeze-up.
A flow switch is available from McQuay under ordering number 017503300. It is a paddletype 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 14.
Installation should be as shown in Figure 20.
Electrical connections in the unit control center should be made at terminals 60 and 67.
Terminals Y and R 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) and have
an insulation rating of 600 volts.
Table 14, Flow Switch Flow Rates
(NOTE !)
Min.
Adjst.
Max.
Adjst.
Flow
Flow Lpm 0.8 1.1 2.2 2.8 4.3 11.4 22.9 35.9 38.6
Flow
Flow Lpm 2.8 4.1 6.1 7.3 11.4 27.7 53.4 81.8 90.8
NOTES:
1. A segmented 3-inch paddle (1, 2, and 3 inches) is furnished mounted, plus a 6-inch paddle loose.
2. Flow rates for a 2-inch paddle trimmed to fit the pipe.
3. Flow rates for a 3-inch paddle trimmed to fit the pipe.
4. Flow rates for a 3-inch paddle.
5. Flow rates for a 6-inch paddle
inch 1 1/4 1 1/2 2 2 1/2 3 4 5 6 8 Pipe Size
mm 32 (2) 38 (2) 51 63 (3) 76 102 (4) 127 (4) 153 (4) 204 (5)
gpm 5.8 7.5 13.7 18.0 27.5 65.0 125.0 190.0 205.0
Lpm 1.3 1.7 3.1 4.1 6.2 14.8 28.4 43.2 46.6
gpm 3.7 5.0 9.5 12.5 19.0 50.0 101.0 158.0 170.0
No
gpm 13.3 19.2 29.0 34.5 53.0 128.0 245.0 375.0 415.0
Lpm 3.0 4.4 6.6 7.8 12.0 29.1 55.6 85.2 94.3
gpm 12.5 18.0 27.0 32.0 50.0 122.0 235.0 360.0 400.0
No
22 IMM AGS-DP
Figure 20, Flow Switch
Valve
Protect All Field Piping
Flow direction marked
on switch
1" (25mm) NPT flow
switch connection
Tee
1 1/4" (32mm) pipe
dia. min. after switch
1 1/4" (32mm) pipe
dia. min. before switch
Figure 21, Typical Field Water Piping
Vent
In
Out
Drain
Valved
Pressure
Gauge
Water
Strainer
Vibration
Eliminator
Notes:
1. Connections for vent and drain fittings are located on the top and bottom of both evaporator water heads.
2. Piping must be supported to avoid putting strain on the evaporator nozzles.
Vibration
Eliminator
Gate
Flow
Switch
Balancing
Valve
Against Freezing
Gate
Valve
Water Connections
Water piping to the evaporator must be brought out through the side of the unit between the
vertical supports. The dimensional drawings on page 28 and following give the necessary
dimensions and locations for all piping connections. Evaporator piping connections face
toward the left side of the unit when looking at control panel #3.
Refrigerant Charge
All units are designed for use with R-134a and are shipped with a full operating charge. The
operating charge for each unit is shown in the Physical Data Tables beginning on page 26.
IMM AGS-DP 23
Glycol Solutions
When using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and
pressure drop through the evaporator can be calculated using the following formulas and
tables.
Note: The following procedure does not specify the type of glycol. Use the derate factors
found in Table 15 for corrections when using ethylene glycol and those in Table 16 for
propylene glycol.
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