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Cooling Tower Marley MD
User Manual
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SPX Cooling Technologies Cooling Tower Marley MD User Manual

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Page 1
Marley MD Cooling Tower
/
/
Engineering Data & Specifications
Page 2
Page 3
Marley / MD Cooling Tower / Table of Contents
Schematic 6 Support 22 Outlet Connection 24 Hoisting Info 25 Freeze Prevention 26 Water Quality 27
Specifications / Base
Base 28 Thermal Performance 28 Performance Warranty 28 Design Loading 29 Construction 29 Mechanical Equipment 29 Fill, Louvers and Drift Eliminators 31 Hot Water Distribution System 31 Casing and Fan Guard 31 Access 31 Collection Basin 32 Warranty 32
Specifications / Options
Stainless Steel Options
Stainless Steel Collection Basin 33 All Stainless Steel Cooling Tower 33
Convenience and Safety Options
Mechanical Access Platform 34 Ladder Extension 34 Ladder Safety Cage 34
Control Options
Fan Motor Starter Control Panel 35 Vibration Limit Switch 36 Basin Heater 36 Fan Motor Variable Speed Drive 36
Miscellaneous Options
Equalizer Flume Weir Gates 38 Premium Efficiency Motor 38 Sound Control 39
Page 4
Marley / MD Cooling Tower
/
■ Air Movement Package
High efficiency fan—wide-chord design for maximum efficiency at low fan tip speeds
Eased inlet fan cylinder—ensures full area, low turbulent airflow through the cylinder
Spherical roller bearings are rated at an L10 life of 100,000 hours
TEFC Fan Motor—1.15 service factor, variable torque, and specially insulated for cooling tower duty
The MD Series air movement package including the structural support—guaranteed against failure for a
period of five full years. The motor is warranted separately by the motor manufacturer
4
■ Water Distribution System
Pressurized spray system distributes water evenly over the fill
Low-clog polypropylene nozzles—delivers precise distribution of water over the fill area
Marley MC thermoformed PVC film fill assembled into packs for ease of removal and cleaning
Marley XCEL drift eliminators—limit drift losses to no more than .001% of the design GPM flow rate
■ Structure
Induced-draft, counterflow design may require less plan area than crossflow towers typically use
Series 300 stainless steel, 316 stainless steel or heavy mill galvanized steel construction
Factory assembled—ensures final field installation will be hassle-free
Triple-pass PVC inlet louvers—limits splash-out and
eliminate sunlight from entering the collection basin
Page 5
Marley / MD Cooling Tower
/
5
towers are galvanized steel, factory
MD
designed to serve air conditioning and refrigeration systems as well as light to medium industrial process loads on clean water. The Marley MD evolved from a factory-assembled concept of towers pioneered by Marley some 75 years ago, and incorporate all of the design advancements that our customers have found valuable. MD towers represent the current state of the art in this cooling tower category.
The specifications portion of this publication not only relates the language to use in describing an appropriate MD cooling tower—but also defines why certain items and features are important enough to specify with the intention of insisting upon compliance by all bidders. The left hand column of pages 28 through 39 provides appropriate text for the various specification paragraphs, whereas the right hand
assembled, counterflow cooling towers,
column comments on the meaning of the subject matter and explains its value.
Pages 33 through 39 indicate those paragraphs which will result in the purchase of a basic cooling tower—one that accomplishes the specified thermal performance, but which will lack many operation—and maintenance-enhancing accessories and features that are usually desired by those persons who are responsible for the continuing operation of the system of which the cooling tower is part. It will also incorporate those standard materials which testing and experience has proven to provide acceptable longevity in normal operating conditions.
Pages 33 through 39 provide paragraphs intended to add those features, components, and materials that will customize the cooling tower to meet the user‘s requirements.
Page 6
Marley / MD Cooling Tower / Engineering Data : Schematic
H
A
569
140
2578
2731
35
8" INLET MOTOR
C
L
PLAN
SIDE ELEVATION END ELEVATION
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
MD5008 SINGLE CELL
6
Page 7
Marley / MD Cooling Tower / Engineering Data : Schematic
165
MD5008 SINGLE CELL
7
Model
note 2
MD5008MAC1L
MD5008MLC1L 163 5.5 79
MD5008NAC1L 179 7. 5 81
MD5008NLC1L 179 7. 5 79
MD5008PAC1L 202 11 81
MD5008PLC1L 202 11 80
MD5008QAC1L 216 15 81
MD5008QLC1L 216 15 80
MD5008MAD1L 180 5.5 80
MD5008MLD1L 177 5.5 79
MD5008NAD1L 197 7. 5 81
MD5008NLD1L 196 7. 5 79
MD5008PAD1L 223 11 81
MD5008PLD1L 223 11 80
MD5008QAD1L 239 15 81
MD5008QLD1L 238 15 80
MD5008MAF1L 189 5.5 80
MD5008MLF1L 185 5.5 79
MD5008NAF1L 207 7. 5 81
MD5008NLF1L 206 7. 5 79
MD5008PAF1L 234 11 81
MD5008PLF1L 234 11 80
MD5008QAF1L 255 15 81
MD5008QLF1L 257 15 80
Nominal Tons
note 3
Motor
kW
5.5 80
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
3294 2181 3051 1702 891
3599 2486 3176 1828 936
3904 2791 3302 1953 1062
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain
current drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 8
Marley / MD Cooling Tower / Engineering Data : Schematic
H
INSTALLED
HEIGHT
A
35
MOTOR
C
L
PLAN
SIDE ELEVATION END ELEVATION
8" INLET
C
L
569
2578
2371
2794
140
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
MD5008 MULTICELL
8
Page 9
Marley / MD Cooling Tower / Engineering Data : Schematic
165
MD5008 MULTICELL
9
Model
note 2
MD5008MAC2L
MD5008MLC2L 165 5.5 79
MD5008NAC2L 179 7. 5 81
MD5008NLC2L 179 7. 5 79
MD5008PAC2L 202 11 81
MD5008PLC2L 202 11 80
MD5008QAC2L 217 15 81
MD5008QLC2L 217 15 80
MD5008MAD2L 180 5.5 80
MD5008MLD2L 180 5.5 79
MD5008NAD2L 196 7. 5 81
MD5008NLD2L 196 7. 5 79
MD5008PAD2L 222 11 81
MD5008PLD2L 222 11 80
MD5008QAD2L 239 15 81
MD5008QLD2L 239 15 80
MD5008MAF2L 188 5.5 80
MD5008MLF2L 188 5.5 79
MD5008NAF2L 205 7. 5 81
MD5008NLF2L 205 7. 5 79
MD5008PAF2L 234 11 81
MD5008PLF2L 234 11 80
MD5008QAF2L 251 15 81
MD5008QLF2L 251 15 80
Nominal Tons
note 3
Motor
kW
5.5 80
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
3526 2413 3072 1723 891
3831 2718 3197 1848 957
4136 3023 3323 1974 1083
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain
current drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration. Change as appropriate for your selection.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" dia. M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
Page 10
Marley / MD Cooling Tower / Engineering Data : Schematic
H
A
35
8" INLET
MOTOR
C
L
PLAN
SIDE ELEVATION END ELEVATION
569
2578
3651
140
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
MD5010 SINGLE CELL
10
Page 11
Marley / MD Cooling Tower / Engineering Data : Schematic
248
MD5010 SINGLE CELL
11
Model
note 2
MD5010PAC1L
MD5010PLC1L 249 11 80
MD5010QAC1L 269 15 81
MD5010QLC1L 270 15 80
MD5010RAC1L 286 18.5 81
MD5010RLC1L 289 18.5 80
MD5010PAD1L 279 11 81
MD5010PLD1L 280 11 80
MD5010QAD1L 304 15 81
MD5010QLD1L 305 15 80
MD5010RAD1L 325 18.5 81
MD5010RLD1L 329 18.5 80
MD5010PAF1L 293 11 81
MD5010PLF1L 294 11 80
MD5010QAF1L 317 15 81
MD5010QLF1L 318 15 80
MD5010RAF1L 341 18.5 81
MD5010RLF1L 346 18.5 80
MD5010SAF1L 360 22 81
MD5010SLF1L 362 22 81
Nominal Tons
note 3
Motor
kW
11 81
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
3412 2299 3883 2079 1052
3717 2604 4046 2242 1190
4021 2909 4234 2430 1353
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 12
Marley / MD Cooling Tower / Engineering Data : Schematic
H
A
35
8" INLET
MOTOR
C
L
C
L
PLAN
SIDE ELEVATION END ELEVATION
569
2578
3651
3715
140
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
MD5010 MULTICELL
12
Page 13
Marley / MD Cooling Tower / Engineering Data : Schematic
248
MD5010 MULTICELL
13
Model
note 2
MD5010PAC2L
MD5010PLC2L 249 11 80
MD5010QAC2L 269 15 81
MD5010QLC2L 270 15 80
MD5010RAC2L 286 18.5 81
MD5010RLC2L 289 18.5 80
MD5010PAD2L 279 11 81
MD5010PLD2L 280 11 80
MD5010QAD2L 304 15 81
MD5010QLD2L 305 15 80
MD5010RAD2L 325 18.5 81
MD5010RLD2L 329 18.5 80
MD5010PAF2L 293 11 81
MD5010PLF2L 294 11 80
MD5010QAF2L 317 15 81
MD5010QLF2L 318 15 80
MD5010RAF2L 341 18.5 81
MD5010RLF2L 346 18.5 80
MD5010SAF2L 360 22 81
MD5010SLF2L 362 22 81
Nominal Tons
note 3
Motor
kW
11 81
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
3628 2515 3906 2102 1052
3932 2820 4069 2265 1213
4237 3124 4256 2453 1376
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration. Change as appropriate for your selection.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 14
Marley / MD Cooling Tower / Engineering Data : Schematic
H
A
3607
3651
35
8" INLET
ACCESS
C
L
PLAN
SIDE ELEVATION END ELEVATION
153
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
MD5016 SINGLE CELL
14
Page 15
Marley / MD Cooling Tower / Engineering Data : Schematic
317
MD5016 SINGLE CELL
15
Model
note 2
MD5016PAC1L
MD5016PLC1L 320 11 78
MD5016QAC1L 345 15 80
MD5016QLC1L 348 15 79
MD5016RAC1L 369 18.5 80
MD5016RLC1L 372 18.5 79
MD5016SAC1L 390 22 81
MD5016SLC1L 394 22 80
MD5016PAD1L 350 11 79
MD5016PLD1L 353 11 78
MD5016QAD1L 383 15 80
MD5016QLD1L 384 15 79
MD5016RAD1L 410 18.5 80
MD5016RLD1L 412 18.5 79
MD5016SAD1L 436 22 81
MD5016SLD1L 437 22 80
MD5016TAD1L 475 30 82
MD5016TLD1L 471 30 80
MD5016PAF1L 368 11 79
MD5016PLF1L 370 11 78
MD5016QAF1L 403 15 80
MD5016QLF1L 401 15 79
MD5016RAF1L 431 18.5 80
MD5016RLF1L 431 18.5 79
MD5016SAF1L 460 22 81
MD5016SLF1L 459 22 80
MD5016TAF1L 500 30 82
MD5016TLF1L 493 30 80
Nominal Tons
note 3
Motor
kW
11 79
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
4239 2529 5805 3225 1710
4544 2834 6089 3508 1763
4848 3139 6320 3739 1977
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 16
Marley / MD Cooling Tower / Engineering Data : Schematic
H
A
3607
3651
3715
35
8" INLET
ACCESS
C
L
C
L
PLAN
SIDE ELEVATION END ELEVATION
153
MD5016 TWO OR THREE CELL
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
16
Page 17
Marley / MD Cooling Tower / Engineering Data : Schematic
317
MD5016 TWO OR THREE CELL
17
Model
note 2
MD5016PAC2L
MD5016PLC2L 320 11 78
MD5016QAC2L 345 15 80
MD5016QLC2L 348 15 79
MD5016RAC2L 369 18.5 80
MD5016RLC2L 372 18.5 79
MD5016SAC2L 390 22 81
MD5016SLC2L 394 22 80
MD5016PAD2L 350 11 79
MD5016PLD2L 353 11 78
MD5016QAD2L 383 15 80
MD5016QLD2L 384 15 79
MD5016RAD2L 410 18.5 80
MD5016RLD2L 412 18.5 79
MD5016SAD2L 436 22 81
MD5016SLD2L 437 22 80
MD5016TAD2L 475 30 82
MD5016TLD2L 471 30 80
MD5016PAF2L 368 11 79
MD5016PLF2L 370 11 78
MD5016QAF2L 403 15 80
MD5016QLF2L 401 15 79
MD5016RAF2L 431 18.5 80
MD5016RLF2L 431 18.5 79
MD5016SAF2L 460 22 81
MD5016SLF2L 459 22 80
MD5016TAF2L 500 30 82
MD5016TLF2L 493 30 80
Nominal Tons
note 3
Motor
kW
11 79
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
4547 2837 5860 3279 1710
4852 3142 6143 3563 1800
5156 3447 6375 3794 2032
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration. Change as appropriate for your selection.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 18
Marley / MD Cooling Tower / Engineering Data : Schematic
H
A
3607
3651
3715
35
8" INLET
ACCESS
C
L
C
L
PLAN
SIDE ELEVATION END ELEVATION
153
MD5016 FOUR OR MORE CELLS
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
18
Page 19
Marley / MD Cooling Tower / Engineering Data : Schematic
317
MD5016 FOUR OR MORE CELLS
19
Model
note 2
MD5016PAC4L
MD5016PLC4L 320 11 78
MD5016QAC4L 345 15 80
MD5016QLC4L 348 15 79
MD5016RAC4L 369 18.5 80
MD5016RLC4L 372 18.5 79
MD5016SAC4L 390 22 81
MD5016SLC4L 394 22 80
MD5016PAD4L 350 11 79
MD5016PLD4L 353 11 78
MD5016QAD4L 383 15 80
MD5016QLD4L 384 15 79
MD5016RAD4L 410 18.5 80
MD5016RLD4L 412 18.5 79
MD5016SAD4L 436 22 81
MD5016SLD4L 437 22 80
MD5016TAD4L 475 30 82
MD5016TLD4L 471 30 80
MD5016PAF4L 368 11 79
MD5016PLF4L 370 11 78
MD5016QAF4L 403 15 80
MD5016QLF4L 401 15 79
MD5016RAF4L 431 18.5 80
MD5016RLF4L 431 18.5 79
MD5016SAF4L 460 22 81
MD5016SLF4L 459 22 80
MD5016TAF4L 500 30 82
MD5016TLF4L 493 30 80
Nominal Tons
note 3
Motor
kW
11 79
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
4801 3091 5933 3353 1710
5106 3396 6217 3636 1874
5410 3701 6448 3868 2105
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative. All table data is per cell.
2 Last two characters of the model number indicate number of
cells and cell configuration. Change as appropriate for your selection.
3 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m
3
/hr per ton. The Marley UPDATE web-based
selection software provides MD model recommendations based on specific design requirements.
4 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 20
Marley / MD Cooling Tower / Engineering Data : Schematic
A
H
7366
7312
3715
35
8" INLET
ACCESS
C
L
C
L
PLAN
SIDE ELEVATION END ELEVATION
153
MD5016 FOUR CELL QUAD
Use this data for preliminary layouts only. Obtain current drawing from your Marley sales representative.
The UPDATE web-based selection software —available at spxcooling.com—provides MD model recommendations based on customer's specific design requirements.
20
Page 21
Marley / MD Cooling Tower / Engineering Data : Schematic
317
MD5016 FOUR CELL QUAD
21
Model
note 2
MD5016PAC4B
MD5016PLC4B 320 11 78
MD5016QAC4B 345 15 80
MD5016QLC4B 348 15 79
MD5016RAC4B 369 18.5 80
MD5016RLC4B 372 18.5 79
MD5016SAC4B 390 22 81
MD5016SLC4B 394 22 80
MD5016PAD4B 350 11 79
MD5016PLD4B 353 11 78
MD5016QAD4B 383 15 80
MD5016QLD4B 384 15 79
MD5016RAD4B 410 18.5 80
MD5016RLD4B 412 18.5 79
MD5016SAD4B 436 22 81
MD5016SLD4B 437 22 80
MD5016TAD4B 475 30 82
MD5016TLD4B 471 30 80
MD5016PAF4B 368 11 79
MD5016PLF4B 370 11 78
MD5016QAF4B 403 15 80
MD5016QLF4B 401 15 79
MD5016RAF4B 431 18.5 80
MD5016RLF4B 431 18.5 79
MD5016SAF4B 460 22 81
MD5016SLF4B 459 22 80
MD5016TAF4B 500 30 82
MD5016TLF4B 493 30 80
Nominal Tons
note 3
Motor
kW
11 79
dBA
1.5m from air inlet face
Dimensions
H A Weight/Cell
4801 3091 5933 3353 1710
5106 3396 6217 3636 1874
5410 3701 6448 3868 2105
Design
Operating
Weight
kg
Shipping Weight
kg
Heaviest
Section
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative. All table data is per cell.
2 Nominal tons are based upon 35°C HW, 29.5°C CW, 25.5°C
WB and .68 m selection software provides MD model recommendations based on specific design requirements.
3
/hr per ton. The Marley UPDATE web-based
3 Standard overflow is a 3"
dia. M connection located on the
side of the collection basin. Makeup water connection is 2" M connection located on the side of the tower. A 3" M drain connection is located on the side of the collection basin.
dia.
Page 22
Marley / MD Cooling Tower / Engineering Data: Support
DE E
C
L
ANCHOR BOLT
C
L
ANCHOR
BOLT
OVERALL OF BASIN
L
C
C
L
ANCHOR
BOLT
C
L
ANCHOR
BOLT
W OVERALL WIDTH OF BASIN
HOLES FOR M16 ANCHOR BOLTS 4 REQD
21
21
TOWER COLLECTION BASIN
A
NORMAL GAUGE
21
SUPPORT
BY OTHERS
TOWER COLLECTION BASIN
22
Model
MD5008__C
MD5008__D
MD5008__F
MD5010__C
MD5010__D
MD5010__F
MD5016__C
MD5016__D
MD5016__F
VIEW A
SUPPORTING STEEL
SINGLE CELL
W L C D E F
2578 2731 2537 2629 51 165 3072 563
2578 2731 2537 2629 51 165 3197 586
2578 2731 2537 2629 51 165 3323 609
2578 3651 2537 3550 51 165 3906 549
2578 3651 2537 3550 51 165 4069 568
2578 3651 2537 3550 51 165 4256 592
3607 3651 3566 3397 127 318 5860 908
3607 3651 3566 3397 127 318 6143 951
3607 3651 3566 3397 127 318 6375 982
Dimensions Design
Operating
Weight
per cell
kg
Design
Operating Load
at support beam
kg/m
Page 23
Marley / MD Cooling Tower / Engineering Data: Support
D F EE
C
L
ANCHOR BOLT
C
L
ANCHOR
BOLT
21
21
OVERALL LENGTH OF BASIN
C
L
ANCHOR BOLT
C
L
ANCHOR
BOLT
C
C
L
ANCHOR
BOLT
C
L
ANCHOR
BOLT
W OVERALL WIDTH OF BASIN
TOWER COLLECTION BASIN
A
HOLES FOR M16 ANCHOR BOLTS 4/CELL
23
SUPPORTING STEEL
MULTICELL
NOTE
1 Use this bulletin for preliminary layouts only. Obtain current
drawings from your Marley sales representative for final design.
2 Purchaser to provide tower support complete with holes and
anchor bolts. Do not use studs! Anchor points must be framed flush and level at top.
3 Design operating weight occurs with collection basin full to
overflow level. Actual operating weight varies with m3/hr and piping scheme.
4 Tower may be placed on a flat concrete slab. Side outlet and
optional side drain and overflow must be specified.
Page 24
Marley / MD Cooling Tower / Engineering Data : Outlet Connection
A
B
C
D
C
L
TOWER
PUMP SUCTION
MAKEUP
2" NPTM
MAKEUP
ALTERNATE LOCATION
OVERFLOW
3" NPTF
89
SUCTION HOOD
WELDING
BEVEL
MECHANICAL COUPLING GROOVE
REMOVABLE TRASH SCREEN
23
DRAIN
3" NPTF
B
C
L
TOWER
C
L
SUMP
SUMP FACE MAY
BE ROTATED 90° OR 180°
MAKEUP
2" NPTM
MAKEUP
ALTERNATE LOCATION
OVERFLOW
3" NPTF
153
502
ANTI-VOTEX PLATE
WITH SCREEN OR
REMOVABLE TRASH SCREEN
DRAIN
3" NPTF
DRAIN
11/2" NPTF
OUTLET PIPING
BY OTHERS
C
L
OUTLET
C
D
89
A
C
D
PUMP SUCTION
MAKEUP
2" NPTM
OVERFLOW
3" NPTF
89
496
878
SLOPING
BASIN FLOOR
DRAIN
3" NPTF
SUCTION SECTION
SIDE-OUTLET SUCTION CONNECTION
Dimensions
Model
MD5008
MD5010
MD5016
END-OUTLET SUCTION CONNECTION
Suction
Diameter
6" — 493 588 305 8" 191 493 588 305
10" — 493 588 305
6" — 477 588 305 8" 191 477 588 305
10" — 477 588 305
6" — 477 639 331
8" 191 477 639 331 10" 216 477 639 331 12" — 477 639 331
A B C D
24
BOTTOM OUTLET
CONNECTION
SIDE-OUTLET SUMP CONNECTION
Maximum m3/hr per Outlet
Outlet
Diameter
6" 144 144 144 205 205 205 76
8" 259 338 355 248 248 248 259 338 355 136 136 136
10" 493 259 338 391 259 338 493 96 101 215 215 215
12" 493 493 142 143 143 259 304 304
14" 173 173 173 259 338 368
16" 226 226 226 259 338 480
18" 259 286 286 259 338 493
20" 338 355 338 493
24" 493 493
Side or End Suction
pump flow
MD5008 MD5010 MD5016 MD5008 MD5010 MD5016 MD5008 MD5010 MD5016 MD5008 MD5010 MD5016 MD5008 MD5010 MD5016
Sump
pump flow
without
anti-vortex plate
Sump
pump flow
with anti-vortex plate or
gravity flow
with or without
anti-vortex plate
SUMP SECTION
Bottom Outlet
pump flow
without
anti-vortex plate
Bottom Outlet
plump flow
with anti-vortex plate or
gravity flow
with or without
anti-vortex plate
Page 25
Marley / MD Cooling Tower / Engineering Data : Hoisting
OFFSET MAY BE REQUIRED FOR BALANCED LIFT
CENTER OF TOWER
CENTER OF TOWER
WIDTH
WIDTH
LIFTING SLING
LIFTING SLING
70° MAX BOTH MODULES
OFFSET MAY BE REQUIRED FOR BALANCED LIFT
25
NOTE
1 Hoisting operations can be dangerous and suitable safety
precautions should be taken to protect personnel and the equipment being hoisted.
2 All hoisting equipment should be certified and comply with
local and national safety regulations.
Base Module Top Module
Model
MD5008 2.6m 3m 110 0 2.8m 3m 900
MD5010 2.6m 4m 1350 2.6m 3m 1050
MD5016 3.7m 4m 1650 3.7m 3m 1750
Width
Sling Length
Minimum
Weight
kg
Width
Sling Length
Minimum
Weight
kg
3 Ensure that slings are of sufficient length so not to impose
bending loads onto the casing—use of spreader bars is essential.
4 For overhead lifts or where additional safety is required, add
slings beneath the tower unit
Page 26
Marley / MD Cooling Tower / Engineering Data: Freeze Prevention
26
When the ambient air temperature falls below 0°C,
the water in a cooling tower can freeze. Marley Technical
Report #H-003 “Operating Cooling Towers in Freezing Weather” describes how to prevent freezing during
operation. Available at spxcooling.com or ask your Marley sales representative for a copy.
During shutdown, water collects in the cold water basin and may freeze solid. You can prevent freezing by adding heat to the water left in the tower—or, you can drain the tower and all exposed pipework at shutdown.
Electric Basin Heaters
An automatic basin water heater system is available consisting of the following components:
• Standardweatherproof(IP55)enclosure,rating
depending on model and minimum expected winter temperature.
• RatingsareinkWforspecifiedambienttemperature.
For lower ambient temperatures refer to SPX engineering for advice.
• Standardelectircalsupplyis380/415V3ph(220/240V1
phavailableasextracostoption).
• Heaterhasanintegralthermostat,setpointnominally
3°C but adjustable to suit operating requirements.
Heater components are normally shipped separately for installation by others.
Note: any exposed piping that is still filled with water at shutdown—including the makeup water line—should
beelectricallytracedandinsulated(byothers).
Indoor Storage Tank
With this type of system, water flows from an indoor tank, through the load system, and back to the tower, where it is cooled. The cooled water flows by gravity from the tower to the tank located in a heated space. At shutdown, all exposed water drains into the tank, where it is safe from freezing.
The amount of water needed to successfully operate the system depends on the tower size and GPM and on the volume of water contained in the piping system to and from the tower. You must select a tank large enough to contain those combined volumes—plus a level sufficient to maintain a flooded suction on your pump. Control makeup water according to the level where the tank stabilizes during operation.
Page 27
Marley / MD Cooling Tower / Engineering Data: Water Quality
27
The MD cooling tower can be a very effective air washer. Atmospheric dust able to pass through the relatively small louver openings will enter the recirculating water system. Increased concentrations can intensify systems maintenance by clogging screens and strainers— and smaller particulates can coat system heat transfer surfaces. In areas of low flow velocity—such as the collection basin—sedimentary deposits can provide a breeding ground for bacteria.
In areas prone to dust and sedimentation, you should consider installing some means for keeping the collection basin clean. Typical devices include side stream filters and a variety of filtration media.
Blowdown
Blowdown or Bleedoff is the continuous removal of a small portion of the water from the open recirculating system. Blowdown is used to prevent the dissolved solids from concentrating to the point where they will form scale. The amount of blowdown required depends on the cooling range—the difference between the hot and cold water temperatures of the closed circuit— and the composition of the makeup water.
CAUTION
The MD cooling tower must be located at such distance and direction to avoid the possibility of contaminated discharge air being drawn into building fresh air intake ducts. The purchaser should obtain the services of a Licensed professional Engineer or Registered Architect to certify that the location of the cooling tower is in compliance with applicable air pollution, fire and clean air codes.
Water Treatment
To control the buildup of dissolved solids resulting from water evaporation, as well as airborne impurities and biological contaminants including Legionella, an effective consistent water treatment program is required. Simple blowdown may be adequate to control corrosion and scale, but biological contamination can only be controlled with biocides.
An acceptable water treatment program must be compatible with the variety of materials incorporated in a cooling tower—ideally the pH of the recirculating water should fall between 6.5 and 9.0. Batch feeding of the chemicals directly into the cooling tower is not a good practice since localized damage to the cooling tower is possible. Specific startup instructions and additional water quality recommendations can be found in the MD Cooling Tower User Manual which accompanies the cooling tower and also is available at spxcooling.com.
Page 28
Specifications
Specification Value
Marley / MD Cooling Tower / Specifications: Base
28
1.0 Base:
1.1 Furnish and install an induced-draft,
counterflow-type, factory assembled, film fill, industrial duty, cooling tower.
Unitshallconsistof_____cell(s),as
shown on plans. The limiting overall dimensions of the tower shall be _____ wide, _____ long, and _____ high. Total operating power of all fans shall not exceed _____ kW, consisting of_____
@_____kWmotor(s).Towershallbe
Marley Model _____________________.
2.0 Thermal Performance:
2.1 The tower shall be capable of cool-
ing _____ m °C to _____ °C at a design entering air wet-bulb temperature of _____ °C. The thermal performance rating shall be Certified by the Cooling Technology Institute. Tower shall comply with all
ASHRAE90.1standards.
3
/hr of water from ____
■ Your specification base establishes the type, configuration, base materi-
al, and physical limitations of the cooling tower to be quoted. During the planning and layout stages of your project, you will have focused your attention on a cooling tower selection that fits your space allotment, and whose power usage is acceptable. Limitations on physical size and total operating horsepower avoid the introduction of unforeseen operational and site-related influences. Specifying the number of cells, and the max­imum fan hp/cell will work to your advantage. You are specifying a counterflow tower, which is a type noted—and usu­ally specified—for its economical use of plan area on projects where the required thermal performance is very difficult. It effectively replaces most makes of older towers—both forced-draft and induced-draft—with­out major redesign of the existing site.
■ CTI Certification means that the cooling
tower has been tested under operat­ing conditions and found to perform as rated by the manufacturer under those circumstances. It assures the buyer that the tower is not intentionally or inadver­tently undersized by the manufacturer.
3.0 Performance Warranty:
3.1 CTI Certification notwithstanding, the
cooling tower manufacturer shall guar­antee that the cooling tower supplied will meet the specified performance conditions when the tower is installed as shown on the plans. If, because of a suspected thermal performance defi­ciency, the owner chooses to conduct an on-site thermal performance test under the supervision of a qualified, disinterested third party in accordance with CTI, ASME or other applicable standards during the first year of oper­ation; and if the tower fails to perform within the limits of test tolerance; then the cooling tower manufacturer will pay for the cost of the test and will make such corrections as are appro­priate and agreeable to the owner to compensate for the performance defi­ciency.
■ However, CTI certification alone is not sufficient to assure you that the
cooling tower will perform satisfactorily in your situation. Certification is established under relatively controlled conditions, and cooling towers seldom operate under such ideal circumstances. They are affected by nearby structures, machinery, enclosures, effluent from other sources, etc. Responsible and knowledgeable bidders will take such site-specific effects into consideration in selecting the cooling tower—but the speci­fier must insist by the written specification that the designer/manufac­turer guarantee this “real world” performance. Any reluctance on the part of the bidder should cause you some concern.
Page 29
Specifications
Specification Value
Marley / MD Cooling Tower / Specifications: Base
29
4.0 Design Loading:
4.1 The tower and its components shall be
designed to withstand a wind load of
1.44kPa. The cooling tower shall be de­signed to withstand shipping and hoist­ing loads of 2g horizontal or 3g vertical. Guardrails, where specified shall be capable of withstanding a 890N con­centrated live load in any direction and shall be designed in accordance with OSHA guidelines.
5.0 Construction:
5.1 Except where otherwise specified,
all components of the cooling tower shall be fabricated of heavy-gauge steel, protected against corrosion by EN10142:2000 grade Z600 galvaniz­ing. After passivation of the galvanized
steel(8weeksatpH7-8,andcalcium
hardness and alkalinity at 100-300
mg/Leach),thecoolingtowershallbe
capable of withstanding water having a pH of 6.5 to 9.0; a chloride content up
to500mg/LasNaCl(300mg/LasCl-); asulfatecontent(asSO4)upto250 mg/L;acalciumcontent(asCaCO3) upto500mg/L;silica(asSiO2)upto
150 mg/L; and design operating ranges up to 10°C. The circulating water shall contain no oil, grease, fatty acids, or organic solvents.
■ The indicated design values are the minimum allowables under
accepted design standards. They give you assurance that the cool­ing tower can be shipped, handled, hoisted—and ultimately oper­ated in a normal cooling tower environment. Most MD models will withstand significantly higher wind and seismic loads. If your geo­graphic location dictates higher wind load or seismic load values, please make the appropriate changes, after discussion with your Marley sales representative.
■ In the history of cooling towers, no other coating for carbon steel
has exhibited the success and longevity of galvanization in expo­sure to the normal cooling tower water quality defined at left. No paints or electrostatically-applied coatings, however exotic they may be, can approach galvanization's history of success.
If extended longevity of the cooling tower is required—or unusually harsh operating conditions are expected—consider specifying stain­less steel as either the base construction material, or the material utilized for specific components of your choice. See Stainless Steel Options on page 16.
5.2 The specifications, as written, are intended to indicate those materials that will be capable of withstanding the above water quality in continuing service, as well as the loads described in paragraph 4.1. They are to be regard­ed as minimum requirements. Where component materials unique to indi­vidual tower designs are not specified, the manufacturers shall take the above water quality and load carrying capabili­ties into account in the selection of their materials of manufacture.
6.0 Mechanical Equipment:
6.1 Fan(s)shallbepropeller-type,incorpo-
rating heavy aluminum alloy blades and electrogalvanized hubs. Blades shall be individually adjustable and both stati-
callyanddynamicallybalanced.Fan(s)
➠
■ Propeller-type fans require only half the operating hp of blower-type
fans. However, they should be readily adjustable to permit compen­sation for jobsite conditions. The fans of one manufacturer require the purchase of special positioners for each increment of fan blade pitch. The Marley Power Belt drive system features all-aluminum
➠
Page 30
Specifications
Specification Value
Marley / MD Cooling Tower / Specifications: Base
30
shall be driven through a one-piece
multi-groove,solidbackV-typebelt, sheaves(pulleys),andtaperedroller
bearings. Bearings shall be rated at an L10 life of 100,000 hours, or greater.
Bothmotorandfansheaves(pulleys)
shall be all cast aluminum to prevent premature corrosion.
6.2 Motor(s)shallbe____kWmaximum,
TEFC, variable torque, inverter duty and specially insulated for cooling tower duty. Speed and electrical char-
acteristicsshallbe______RPM,single-
winding, ___ phase, ____ hertz, ____ volts. Motor nameplate power shall not be exceeded at design operation. TEAO motors are not acceptable.
6.3 The complete mechanical equipment assembly for each cell shall be support­ed by a rigid, hot-dip galvanized steel structural support that resists misalign­ment between the motor and sheaves
(pulleys).Forbelt-drivetowerswith
motors inside the airstream, motors shall be mounted on an adjustable base that swivels outside the access door for maintenance. For belt-drive tow­ers with motors mounted outside the airstream, a protective cover shall be mounted over the motor and sheave to protect it from the weather and prevent inadvertent contact. The mechanical equipment assembly shall be warranted against any failure caused by defects in materials and workmanship for no
lessthanve(5)yearsfollowingthe
date of tower shipment. This warranty shall cover the fan, speed reducer, drive shaft and couplings, and the mechanical equipment support. The electric motor shall carry a manufacturer's warranty of at least one year. The bearing assem-
bliesandV-beltsshallbewarrantedfor
18 months.
sheaves, power band belts and long-life bearings for dependable ser­vice.
TEFC motors offer additional benefits over TEAO motors whose only source of cooling is the flow of air produced by the cooling tower fan. This air rate is not always ideal due to motor position, blockage, etc. TEFC ensures the motor will always be cooled properly.
Unless otherwise specified, motor speed will be 1500 RPM in on stan­dard models. Low noise models will use motor speeds appropriate for the specific model. If you prefer the operating flexibility of two-speed operation, please specify two-speed, single-winding motors which offer full and half speeds for maximum energy savings. Incidentally, two speed motors are a far better choice than separate “pony” motors which simply double the problems indicated above and induce parasitic loads during operation for lower than nameplate efficiency.
The value of a 5 year mechanical equipment warranty speaks for itself. Except for the motor, virtually all of the mechanical equipment on a Marley tower is designed and manufactured by SPX Cooling Technologies. Cooling tower vendors who purchase commercial fans, gear reducers, driveshafts, etc. may require that you deal directly with those commercial suppliers for warranty satisfaction.
Page 31
Specifications
Specification Value
Marley / MD Cooling Tower / Specifications: Base
31
7.0 Fill, Louvers and Drift Eliminators:
7.1 Fill shall be cross-corrugated,
counterflow film type, thermoformed
from0.40mmthickPVC.Fillshall
be assembled into packs for ease of removal and cleaning. Fill shall be sup­ported on channel sections supported from the tower structure and have a flame spread rating less than 25. Drift eliminatorsshallbePVCwithamini­mum of three changes in air direction, and shall limit drift losses to no more than 0.001% of the design water flow rate.
7.2 Air inlet louvers shall be a minimum of
127mmairtravel,triplepassPVCto
prevent water splashout and eliminate sunlight from entering the collection basin. For ease of service and long
lifeoflouvers,PVClouversshallbe
enclosed in a removable frame that attaches to the air inlet without tools. Louvers with less than three changes in air direction are unacceptable.
■ Fill modules can be removed for inspection and cleaning in accor-
dance with local anti legioinella guidelines.
Drift rate varies with design water loading and air rate, as well as drift eliminator depth and number of directional changes. The indi­cated rate of 0.001% is easily achievable without premium cost. If a lower rate is required, please discuss with your Marley sales repre­sentative.
8.0 Hot Water Distribution System:
8.1 A pressured spray system shall dis-
tribute water evenly over the fill. The branch arms shall be corrosion resis­tantPVCwithpolypropylenespraynoz­zles attached to the branch arms with a rubber socket connection for ease of removal and cleaning. To ensure proper spray system operation, nozzles shall seat in branch arms without regard for direction or alignment.
9.0 Casing and Fan Guard:
9.1 The casing shall be heavy gauge
EN10142:2000 grade Z600 galvanized steel and shall be capable of with­standing the loads described in para­graph 4.1. Casing panels shall encase the fill on all four sides of the tower. The top of the fan cylinder shall be equipped with a conical, non-sagging, removable fan guard, fabricated of welded 5/16" and 7 gauge rods, and hot dip galvanized after fabrication.
■ The combination of PVC piping and polypropylene nozzles is very
resistant to the build-up of scale and slime.
Page 32
Marley / MD Cooling Tower / Specifications: Base
32
Specifications
10.0 Access:
10.1 A large rectangular access door shall
be located in the plenum on the motor side of the tower.
11.0 Cold Water Collection Basin:
11.1 The collection basin shall be heavy-
gauge galvanized steel and shall include the number and type of suction connections required to accommodate the out-flow piping system shown on the plans. Suction connections shall be equipped with debris screens. A fac­tory installed, float operated, mechani­cal make-up valve shall be included. An overflow and drain connection shall be provided in each cell of the tower. The basin floor shall slope toward the drain to allow complete flush out of debris and silt which may accumu­late. Towers of more than one cell shall include steel flumes for flow and equalization between cells.
13.0 Warranty:
Specification Value
■ The MD tower design offers side-suction as standard. Bottom outlets
may be supplied to accommodate a variety of piping schemes. Unless so specified, the tower you may be asked to approve may only be avail­able with one type of suction connection requiring you to redesign your piping layout.
The sloping floor and low-level drain is valuable because it provides a way to achieve flush-out cleanability.
13.1 The MD cooling tower shall be free from defects in materials and work-
manshipforaperiodofeighteen(18)
months from the date of shipment.
Page 33
Marley / MD Cooling Tower / Specifications: Options
33
Specifications
Stainless Steel Options
Stainless Steel Collection Basin:
11.1 Replace paragraph 11.1 with the
following: The collection basin shall be heavy-gauge Series 300 stainless steel. Only low-carbon stainless steel alloys will be accepted in order to minimize the risk of intergranular cor­rosion in the weld zones. Basin shall include the number and type of suction connections required to accommodate the out-flow piping system shown on the plans. Basin suction connections shall be equipped with debris screens. A factory installed, float operated, mechanical make-up valve shall be included. An overflow and drain con­nection shall be provided in each cell of the tower. The basin floor shall slope toward the drain to allow complete flush out of debris and silt which may accumulate.
All Stainless Cooling Tower
Specification Value
■ The cold water basin is the only part of the tower that is subject to
periods of stagnant water, concentrated with treatment chemicals and customary contaminants. It is also the most expensive and dif­ficult part of any tower to repair or replace. For these reasons, many customers—particularly those who are replacing older towers— choose to specify stainless steel cold water basins.
5.1 Replace paragraph 5.1 with the following: Except where other wise
specified, all components of the cool­ing tower shall be fabricated of heavy­gauge, series 300 stainless steel. Only low-carbon stainless steel alloys will be accepted in order to minimize the risk of intergranular corrosion in the weld zones. The tower shall be capable of withstanding water having a chloride
content(NaCl)upto750mg/L;asul­fatecontent(SO4)upto1200mg/L; acalciumcontent(CaCO3)upto800 mg/L;silica(SiO2)upto150mg/L;and
design operating ranges up to 27.8°C. The circulating water shall contain no oil, grease, fatty acids, or organic sol­vents.
■ For pure resistance to corrosion—coupled with the capability to
meet stringent fire and building codes—there is no substitute for stainless steel. No paints or electostatically-applied coatings, how­ever exotic they may be, can match stainless steel's ability to with­stand adverse operating conditions.
Page 34
Specifications
Marley / MD Cooling Tower / Specifications: Options
34
Specification Value
Convenience and Safety Options
Mechanical Access Platform:
10.2 Add the following paragraph in the Access section: There shall be
a mechanical access platform at the mechanical access door allowing access to the mechanical system, drift eliminators, distribution system and fill. The platform shall be galvanized steel bar grating, supported by galvanized steel framework attached to the tower. The platform shall be surrounded by a guardrail, kneerail, and toeboard designed according to meet local safety requirements. A ladder shall be permanently attached to the platform and to the casing of the tower, rising from the base of the tower to the top of the handrail.
Ladder Extension:
10.2 Add the following to the end of para­graph 10.2: Provide a ladder extension
for connection to the foot of the ladder. This extension shall be long enough to
risefromtheroof(grade)leveltothe
base of the cooling tower. The install­ing contractor shall be responsible for cutting the ladder to length; attaching it to the foot of the cooling tower ladder; and anchoring it at its base.
■ Periodic inspection and maintenance of a cooling tower distribution sys-
tem is fundamental to preserving maximum cooling system efficiency. All cooling towers—crossflow or counterflow—are subject to clogging to varying degrees by waterborne contaminants such as pipe scale and sediment. Therefore, safe and easy access to these components is of significant value to the operator.
Access can be provided in a number of ways, including portable lad­ders or scaffolding, but for maximum safety and convenience, a field installed Marley access platform with guardrails is available to make this task as safe and user-friendly as possible. Further, its location on the side of the tower does not add to the height of the unit, preserving architectural integrity. It also saves the owner time and money, in that maintenance personnel may devote their time to inspection rather than searching for ladders or erection of portable scaffolding.
■ Many cooling towers are installed such that the base of the unit is 60cm
or more above the roof or grade level. This makes it difficult to get up to the foot of the attached ladder. The ladder extension alleviates this problem. Marley ladder extensions are available in standard 1.5m and
3.5 lengths.
Ladder Safety Cage:
10.3 Add the following paragraph in the Access section: A welded aluminum
safety cage shall surround the ladder, extending from a point approximately 2m above the foot of the ladder to the top of the handrail.
Page 35
Specifications
Marley / MD Cooling Tower / Specifications: Options
35
Specification Value
Control Options
Fan Motor Starter Control Panel:
6.4 Add the following paragraph in the Mechanical Equipment sec­tion: Each cell of the cooling tower
shall be equipped with a UL listed control system in a IP52 or IP56 out­door enclosure capable of controlling single-speed or two-speed motors as required, and designed specifically for cooling tower applications. The panel shall include a main fused discon­nect or main circuit breaker with an external operating handle, lockable in the off position for safety. Across-the­line magnetic starters or solid-state soft-start starters as required shall be controlled with a thermostatic or solid-state temperature controller. Door mounted selector switches shall be provided to enable automatic or manual control and wired to meet local control voltage. If required, control cir­cuit to be wired out to terminal blocks for field connection to a remote vibra­tion switch, overload trip alarms and remote temperature control devices. The temperature controller shall be adjustable for the required cold-water temperature. If a thermostatic control­ler is used it shall be mounted on the side of the tower with the temperature sensing bulb installed in the cold water basin using a suspension mounting bracket. If a solid-state temperature controller is used the controller will be door mounted on the control panel. The temperature controller will display two temperatures, one for outgoing water and the other for set point. Water temperature input shall be
obtainedusingathree-wireRTDwith
dry well in the outlet water piping and wired back to the solid-state tempera­ture controller in the control panel.
■ If it is your opinion that the control system for the cooling tower
be part of the cooling tower manufacturer’s responsibility, we are in wholehearted agreement with you. Who better to determine the most efficient mode and manner of a cooling tower’s operation— and to apply a system most compatible with it—than the designer and manufacturer of the cooling tower?
Marley variable speed drives are also available for the ultimate in temperature control, energy management, and mechanical equip­ment longevity.
Page 36
Specifications
Marley / MD Cooling Tower / Specifications: Options
36
Specification Value
Vibration Limit Switch:
6.5 Add the following paragraph in the Mechanical Equipment section: A
single-pole, double-throw vibration limit switch in a NEMA 4 housing shall be installed on the mechanical equipment support for wiring into the fan motor shutdown circuit. The purpose of this switch will be to interrupt power to the motor in the event of excessive vibra­tion. It shall be adjustable for sensitiv­ity, and shall require manual reset.
Basin Heater:
11.2 Add the following paragraph in the Cold Water Provide an electric immer-
sion heater for each cell of the tower to prevent freezing of water in the collection basin during periods of shut­down. The rod type heater is installed in the side of the cold water basin. Each heater will include an integral thermostat, set point nominally 4°C but adjustable to suit local operating requirements.
Fan Motor Variable Speed Drive:
■ Unless specified otherwise, a 3171 switch will
be provided. A double-pole, double-throw model is also available. If purchased in con­junction with the Control System, it is also factory-wired. The requirement for manual reset assures that the tower will be visited to determine the cause of excess vibration.
■ The Marley basin heater components described at left represent our rec-
ommendation for a reliable automatic system for the prevention of basin freezing. They are normally shipped separately for installation at the job­site by the installing contractor. When purchased in conjunction with the enhanced Control System option, however, they are customarily factory­mounted and tested.
Submerged in basin water, in which zinc ions are present, copper immersion heaters must not be used. Insist upon stainless steel.
The ambient air temperature that you insert in the specifications should be the lowest 1% level of winter temperature prevalent at site.
6.4 Add the following paragraph in the Mechanical Equipment section when VFD is used as a stand alone system:
Speed Drive system in a IP52 indoor or
IP563Routdoorenclosureshallbepro­vided.TheVFDshallusePWMtechnol-
ogy with IGBT switching and integrated
bypassdesign.VFDoutputswitching
shall not cause mechanical issues with
gearboxteethordriveshafts.TheVFD
shall catch a fan spinning in the reverse direction without tripping. The panel shall include a main disconnect with short circuit protection and external operating handle, lockable in the off position for safety. The system shall include a solid state, PI temperature controller to adjust frequency output of the drive in response to the tower cold-water temperature. The temperature of the cold water and set point shall be displayed on the door of the control panel. The bypass shall include a complete magnetic bypass
circuitwithcapabilitytoisolatetheVFD
when in the bypass mode. Transfer to the bypass mode shall be automatic in
theeventofVFDfailureorforspecic
trip conditions allowing safe transfer
AcompleteULlistedVariable
■ Marley VFD drive systems are designed to combine absolute tempera-
ture control with ideal energy management. The cooling tower user selects a cold water temperature and the drive system will vary the fan speed to maintain that temperature. Precise temperature control is accomplished with far less stress to the mechanical equipment compo­nents. The improved energy management provides fast payback.
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37
Specification Value
of utility voltage to the motor. Automatic bypass with an earth ground condition is not allowed. The bypass contactor shall be cycled on and off while operating in bypass, to maintain the set-point temperature of the cold water. The drive design shall be oper­ated as a stand- alone system without the need for a BMS system. Operator controls shall be mounted on the front of the enclo­sure and shall consist of start and stop
control,bypass/VFDselectorswitch,Auto/
Manual selector switch, manual speed con­trol, and solid-state temperature controller. An emergency bypass selector switch inter­nal to the panel allowing the cooling tower fan motor to be run at full speed shall be furnished. To prevent heating problems in the cooling tower fan motor and to assure
propergearboxlubricationtheVFDsystem
shall de energize the motor once 25% motor speed is reached and cooling is no
longerrequired.TheVFDshallincludede-
icing logic with auto canceling and adjust­able time. Speed in De-Ice mode shall not exceed 50 % motor speed. The cooling
towermanufacturershallsupplyVFDstart-
up assistance. Tower vibration testing throughout the speed range is required to identify and lockout any natural frequency vibration levels which may exceed CTI guidelines.
6
.4 Add the following paragraph in the
Mechanical Equipment section when VFD is used with customers Building Management System:
listedVariableSpeedDrivesystemina
IP10 indoor, IP52 indoor or IP14 outdoor
enclosureshallbeprovided.TheVFDshall
use PWM technology with IGBT switching
andintegratedbypassdesign.VFDoutput
switching shall not cause mechanical issues
withgearboxteethordriveshafts.TheVFD
shall catch a fan spinning in the reverse direction without tripping. The panel shall include a main disconnect with short circuit protection and external operating handle, lockable in the off position for safety. The VFDsystemshallreceiveaspeedrefer­ence signal from the Building Management System monitoring the tower cold-water temperature. The bypass shall include a complete magnetic bypass circuit and with
capabilitytoisolatetheVFDwheninthe
bypass mode. Transfer to the bypass mode
shallbemanualintheeventofVFDfailure.
Operator controls shall be mounted on the front of the enclosure and shall consist of
A complete UL
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Specification Value
startandstopcontrol,bypass/VFDselec­tion, Auto/Manual selections, manual speed control. To prevent heating prob­lems in the cooling tower fan motor and to assure proper gear reducer lubrication
theVFDsystemshalldeenergizethe
motor once 25% motor speed is reached and cooling is no longer required. The cooling tower manufacturer shall supply
VFDstart-upassistance.Towervibration
testing throughout the speed range is required to identify and lockout any natu­ral frequency vibration levels which may exceed CTI guidelines.
Miscellaneous Options
Equalizer Flume Weir Gates:
11.2 Add the following paragraph under Cold Water Collection Basin: The
interconnecting flume between cells shall be equipped with a removable cover plate to permit the shutdown of one cell for maintenance purposes, or to permit independent cell operation.
■ Where it is your intention to be able to operate both cells of the tower
while the flume cover plate is installed, separate outlet connections, float valves and overflows must be provided for each cell. Likewise, this would require separate sensors and controls for basin heater systems, if installed.
Premium Efficiency Motor
6.3 Replace paragraph 6.3 with the fol­lowing: The complete mechanical
equipment assembly for each cell shall be supported by a rigid, hot-dip galvanized steel structural support that resists misalignment between the
motorandsheaves(pulleys).Forbelt-
drive towers with motors inside the airstream, motors shall be mounted on an adjustable base that swivels outside the access door for maintenance. For belt-drive towers with motors mounted outside the airstream, a protective cover shall be mounted over the motor and sheave to protect it from the weather and prevent inadvertent con­tact. The mechanical equipment assem­bly shall be warranted against any fail­ure caused by defects in materials and
workmanshipfornolessthanve(5)
years following the date of tower ship­ment. This warranty shall cover the fan, speed reducer, motor, drive shaft and couplings, and the mechanical equip­ment support. The bearing assemblies
andV-beltsshallbewarrantedfor18
months.
■ IEC premium efficiency motor with a five year warranty enhances the
standard five year mechanical equipment warranty of the MD cooling tower.
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Specification Value
Sound Control
1.2 Add the following paragraph under Base: The cooling tower shall be quiet
operating, and shall produce an overall level of sound no higher than ____ dBA, measured at the critical location indicated on the plans.
■ Sound produced by a standard MD tower operating in an unob-
structed environment will meet all but the most restrictive noise limitations—and will react favorably to natural attenuation. Where the tower has been sized to operate within an enclosure, the enclosure itself will have a damping effect on sound. Sound also declines with distance—by about 5 or 6 dB(A) each time the dis­tance doubles. Where noise at a critical point is likely to exceed an acceptable limit, you have several options—listed below in ascend­ing order of cost impact:
• In many cases, noise concerns are limited to night time, when
ambient noise levels are lower and neighbors are trying to sleep. You can usually resolve these situations by using two speed motors in either full / half speed or full / 2/3 speed configuration, and operating the fans at reduced speed without cycling “after hours”. (The natural night time reduction in wet-bulb temperature makes this a very feasible solution in most areas of the world, but the need to avoid cycling may cause the cold water temperature to vary significantly.)
• Variable speed drives automatically minimize the tower's noise
level during periods of reduced load and/or reduced ambient without sacrificing the system's ability to maintain a constant cold water temperature. This is a relatively inexpensive solution, and can pay for itself quickly in reduced energy costs.
• Where noise is a concern at all times (for example, near a hos­pital), the best solution is to oversize the tower so it can operate continuously at reduced (2/3 or ½) motor speed even at the highest design wet-bulb temperature. Typical sound reductions are 7 dB(A) at 2/3 fan speed or 10 dB(A) at ½ fan speed, but larger reductions are often possible.
• The most extreme cases may require discharge sound attenuator
sections—however, the static pressure loss imposed by discharge attenuators may necessitate an increase in tower size. Your Marley sales representative will be able to help you meet you sound requirements.
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GREGORY'S BANK WORCESTER WR3 8AB UNITED KINGDOM 44 (0) 1905 720 200 info.uk@spx.com
spxcooling.com
In the interest of technological progress, all products are subject to design and/or material change without notice. ©2008 SPX Cooling Technologies, Inc. uk_MD-TS-08A
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