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FORM NO: MM0101B

MODELS: *AHFS*AHAF*AHBF*AHDFS*AHDAF*AHDBF

Air-HandlingUnits

CentralStation

Products That Perform . . .By People Who Care

®

INSTALLATIONOPERATION ANDMAINTENANCEMANUAL

INSTALLATIONOPERATION ANDMAINTENANCEMANUAL

TABLE OF CONTENTS

SECTION PAGE

NOMENCLATURE ...................................................................................................................... 3

INTRODUCTIONGENERAL ................................................................................................................................................................................ 4RECEIVING............................................................................................................................................................................. 4HANDLING AND RIGGING................................................................................................................................................... 5STORAGE................................................................................................................................................................................ 5

INSTALLATIONLEVELING FAN DECK ASSEMBLY.................................................................................................................................... 6CLEARANCE........................................................................................................................................................................... 6GENERAL PIPING PARAMETERS- HOT WATER COILS.................................................................................. 7

STEAM COILS ............................................................................................ 8DIRECT EXPANSION COILS................................................................... 9

BELT AND SHEAVES............................................................................................................................................................ 9CONDENSATE DRAIN TRAPS.......................................................................................................................................... 10DUCT CONNECTIONS....................................................................................................................................................... 11DAMPER MOTORS AND LINKAGES............................................................................................................................... 12PHYSICAL DIMENSION...................................................................................................................................................... 13UNIT SHIPPING WEIGHTS (LBS)..................................................................................................................................... 14

COMPONENTS ARRANGEMENTDISCHARGE ARRANGEMENTS....................................................................................................................................... 16BLOWER ARRANGEMENT................................................................................................................................................ 16QUICK SERVICE ACCESS ................................................................................................................................................ 18COIL SECTION ..................................................................................................................................................................... 18FAN SECTION ...................................................................................................................................................................... 19MOTOR LOCATION............................................................................................................................................................. 19

UNIT FEATURES AND ACCESSORIESUNIT ASSEMBLY PLANNING............................................................................................................................................ 20TYPICAL ARRANGEMENT................................................................................................................................................ 20FAN BEARINGS.................................................................................................................................................................... 21VIBRATION ISOLATION ..................................................................................................................................................... 21

OPERATIONPRE-OPERATION CHECK................................................................................................................................................. 22PRESSURE DROPS ........................................................................................................................................................... 22

OPERATING LIMITATION ......................................................................................................................................... 23

MAINTENANCEPERIODIC INSPECTION .................................................................................................................................................... 24ANNUAL INSPECTION ....................................................................................................................................................... 24

TROUBLESHOOTING CHART .............................................................................................................................. 25

NOMENCLATURE

Each unit nameplate will carry the unit model designation.

The following gives a sample nomenclature of Dunham-Bush air-handlers

AH FS 100 H L

MODULAR DESIGN

AH= Air Handler SingleSkinned

AHD= Air Handler DoubleSkinned

FS= Forward Curved WheelAF= Air Foil WheelBF= Backward Curved

Unit Size = Nominal CFM100

L= Low Pressure UnitUp To 3.5” TSP

M= Medium PressureUnit Over 3.5” TSP

H= Horizontal V= Vertical

M= Multi Zone

RETURN AIRFAN SECTION

ECONOMIZER PREFILTER,COOLING COIL

AND SUPPLY AIRFAN SECTION

BAG FILTERSECTION

DISCHARGEDAMPER

INTRODUCTION

GENERAL

This manual has been prepared as a guide for installing, operating and maintaining the Dunham-

Bush central station air-handling units. Proper installation, operation and maintenance is essential toensure lower first cost, longer equipment life and high overall operating efficiency.

Dunham-Bush central station air-handling units are designed for cooling, dehumidifying (orhumidifying), heating, ventilating and filtering. It is best suited for high-rise buildings, big industrialplants, hospitals, shopping centres, computer rooms and many other centralised systems. Its

sectionalised design enable full lines of accessories to be attached to accommodate variousapplications.

Every air-handlers is designed and tested by experienced engineers. It is fabricated with rigidgalvanised steel frame work and thick gauge galvanised steel panel for rugged handling operation. Itis subjected to rigid quality control standards to give the most efficient, reliable and economical

performance possible.

RECEIVING

All units leaving Dunham-Bush factory have been thoroughly checked to ensure the shipment of

quality products. We guarantee that all air-handlers are properly packaged.

Cautions: Dunham-Bush Industries Sdn Bhd will not be responsible for any damages or loss parts

in shipment or at the job site. Report any shipping damage to nearest Dunham-Bushoffice immediately.

Carefully inspect all shipments immediately after delivery. When damage is evident, note this facton the carrier's freight bill and request that the carrier send a representative to inspect the damage.This may be done by telephone or in person, but should always be confirmed in writing.

The shipment should be unpacked in the presence of the agent so that the extent of damage or losscan be determined. The carrier's agent will make an inspection report and a copy will be given to the

consignee for forwarding to the carrier with a formal claim. Do not report missing items until youhave thoroughly checked the units because bolts, belts or other small item's might be packed insidethe units.

INTRODUCTION

HANDLING AND RIGGING

Proper handling and rigging procedure should be exercised to prevent damages. Some units are

completely assembled and should be handled carefully to avoid dropping or jarring. Others areshipped in a few sections or completely knock-down. Care is required in handling the individualparts. Fan wheels, casings, coils that are furnished with extra protective coatings must be handled

with extreme care, as an injury to the coating can result in a break of continuity and this will destroypermanently the value of the protective covering for the metal. Any such rupture of coating, due tomishandling, is not covered by the guarantee.

Air handling units are shipped on strong plastic package or crate with sections bolted as determinedby lorries or trailer size limitations. When lifting with slings, use spreader bars across the top of the

units to avoid damaging panel or framework. Caution must be exercised to avoid damages to anysections. Check the weight of the units before rigging. Try to place the rigging cable such that theweight is evenly distributed.

Lifting cables should not be attached to the extremities of the accessory sections withoutintermediate support at the basic units. The feet on the accessory section are provided for isolator

mounting and not designed for rigging connections and must not be abused.

All fan outlets are covered with cardboard. Remove it just prior to when the duct is connected to the

unit.

When the units are to be stored in a warehouse for more than three months, the shaft should be

rotated once every month. Damage to the shaft motors, drive package and coil by transient loadshould be avoided. On no occasion should anything be stacked on top of the units. The elapsed timefor the warranty prevails even though the units are in storage.

STORAGE

If equipment is stored out-of-doors, special care should be taken to protect against moisture,

corrosion and dust. Wheels should be covered to prevent unintended location by wind. Equipment,when stored under such conditions, must be periodically inspected to stop trouble from developing.No special precaution is required when equipment is stored indoors.

INSTALLATION

If your inspection indicates that the unit is ready for installation, move it to the desired location.Evaluate the job site by considering the following points:

( l.) Is the floor or foundation level enough to support the weight of the unit (the minimumfoundation shall be 4 times the rotating mass of the fan and drives or about double of the unitsweight). Refer to table 1 to 5 for weight and dimensions.

( 2.) Is there sufficient space for making piping, drainings and wiring connections, and this spaceaccessible.

( 3.) Is there adequate space for servicing the unit, and for removing or opening the access doors. Aminimum clearance equal to the width of the units must be provided on one side of the unit forremoving the coil, shaft and wheel.

( 4.) How ductwork is to be done and is there enough space for ducting.

In extreme cases when it is necessary to completely isolate any vibration from the air-conditionerwhich can adversely affect any other nearby equipment, it is recommended that either one of thefollowing methods be followed:

( 1.) Provide a separate floating plinth.

( 2.) Place the unit on a minimum 2.5" thick cork sheet.( 3.) Support the complete unit on spring isolators. Request factory to provide correct spring

isolators and mounting brackets at base units.

For stringent quiet and vibration-free application, a good acoustical and vibration engineeringpractice has to be applied.

Ideally, a heavy concrete slab should be used for floor mounted units, and main support beams forceiling hung units. Long floor or ceiling spans should be avoided.

LEVELING FAN DECK ASSEMBLY

After installation, check the fan deck to ensurethat it is level with the foundation. The levelmay be corrected by loosening the cap screw(see Figure 1). To raise the level, turn theadjusting screw anti-clockwise; to lower, turnthe screw clockwise. When the correct level isachieved, firmly tighten the cap screw.

CLEARANCE

Clearance must be provided for

( a.) Supply and return ductwork( b.) Chilled water piping connection( c.) Electrical power and control wiring( d.) Trapped condensate drain connection( e.) Routine services like filter and lubrication( f.) Coil removal

FIGURE 1: SPRING FLOOR MOUNT

Curb mounted and weather-proof units can be provided upon request.

SUPPLY

RETURN

AIR VENT

3 WAY MIXINGVALVE

PROPORTIONAL REMOTEBULB TEMP. CONTROL

GATEVALVE

DIRTLEG WITH GATEVALVE (7/8"OD MIN.)

THERMOMETER

GAGE COCK

PLUG COCK

INSTALLATION

GENERAL PIPING PARAMETERS - HOT WATER COILS

The following precautions should be noted with regard to the piping layout for hot water coils:

( 1.) All coils should be connected to provide adequate venting and drainage.

( 2.) Thermometers are recommended to provide temperature readings when coils are balanced.

( 3.) a. Plug cocks are used to manually adjust the water flow for a set pressure drop through thecoil.

b. The pressure drop is determined by connecting pressure gauges to the gauge cocks

( 4.) The leaving air temperature from the coil (in this piping layout) is maintained by automaticallyproportioning the amount of water flowing through the coil or through the by-pass. The waterflow is regulated by a motorised 3 way mixing valve, controlled through a proportional remotebulb temperature controller.

( 5.) A gate valve and hose connection provided in the supply line dirt leg should be supplied whenfloor drains are remote in relation to the coil location.

( 6.) Water piping and coil section should be supported independently.

Figure 2: Hot Water Coil Piping Layout

INSTALLATION

GENERAL PIPING PARAMETERS -STEAM COILS(MEDIUM OR HIGH PRESSURE SYSTEM)

The following precautions should be noted with regard to the piping layout for steam coils:

( 1.) Return piping from coil to trap should be of at least the same size as the coil outlet connection.

( 2.) Steam piping and coil section should be supported independently.

( 3.) The sizing of control valves should be based on the steam load and not on the coil supplyconnection size.

( 4.) Thermostatic traps should be used for venting only.

( 5.) A strainer should be provided on the steam supply side of the control valve.

( 6.) Locate traps at least 12 inches below the coil return connection.

( 7.) Where handling outside air below 35°F the following precautions must be followed:a. Proper draining is mandatory to avoid damage by freezing.

b. Do not use overhead returns from coils.c. An immersion thermostat should be used to protect the coil. The device controls the

outdoor air damper and fan motor when the steam supply fails or condensate temperaturedrops below a pre-set level. Thermostat is located in the return line before the dirt leg.

FIGURE 3: STEAM COIL PIPING LAYOUT

INSTALLATION

GENERAL PIPING PARAMETERS- DIRECT EXPANSION COILSEach coil must be installed with the suction header on the entering air face of the coil and with thesuction connection at the lower end. The orientation of the refrigerant distributor is not critical butthe distributor tubes must not be kinked or bent in a non-uniform configuration. Refer to, Figure 4.An individual expansion device must be provided for each coil or each section of coil whichcontains a header suction connection. If the air flow through two or more coils is in parallel, as in astacked coil bank, the suction piping must be installed in such a way that liquid from one coilsuction header cannot reach another coil suction header. The bulb for the control valve must beattached to the header of the coil or section of coil fed by that valve and not to a common header.When two or more coils areconnected to a common suction line,never place the bulb on the commonline.

Thermostatic expansion valves are tobe equipped with external equalizertubes that are field connected to thesuction line. The valve should besized in accordance with themanufacturers recommendations,allowing approximately 35 psipressure drop through the coil anddistributor at full load. Do notoversize the valve. Follow the valvemanufacturer's instructions on thelocation of the thermostatic bulb.Proper expansion valve operation isnecessary in order to realize the ratedcoil capacity.

Figure 4: DX Coil Piping Arrangement

When a DX type coil is operated with a suction temperature below 32°F, a build up of frost willoccur on the finned surface. It is, therefore, not recommended to operate DX coils for airconditioning purposes at below freezing suction temperatures. If the full load operating point for thecoil is selected at a "safe" temperature, a system analysis is required to check for the lowest probablesuction temperature at light load conditions. Suction pressure controlled hot gas bypass valves areavailable from various control manufacturers to maintain an adequate minimum suction temperature.

BELTS AND SHEAVES

Improper sheave alignment and belt tension are the most frequent causes of excessive vibration aswell as shortened belt and bearing life. It is important to install the fan sheave as close as practical tothe bearing. Adjust the motor sheave to align with the fan sheave with the use of a straight edge. Formultiple groove sheaves use the center groove of the motor sheave and align this center groove withthe center groove of the fan sheave. Adjust the belt tension.

The best belt tension is the lowest tension at which the belts will not slip under peak load conditions.

SIDE VIEW OF 'AH' DRAIN PAN

SLOPED TO DRAIN

TO DRAIN

DRAIN LINE SLOPED1/4" MIN PER FT

A

B

INSTALLATION

CONDENSATE DRAIN TRAPS

The condensate drain trap piping must be properly designed to insure the removal of condensate.Incorrect trapping can hold water in pan causing overflow. On blow through units, particularly,system air can escape down the drain with incorrect trapping.

a.) On draw-through units (A) shall be equal to or greater than the coil section negative pressure atoperating conditions.

b.) On blow-through units (A) can be as small as 1” but (B) must equal or exceed the total staticpressure in the coil section.

FIGURE 4: TYPICAL CONDENSATE PIPING

DUCT CONNECTIONSAll intake and discharge air duct connections to the unit should be made with flexible material. Theaccessory flexible connectors may be used for this purpose. The flexible material should be installedso that it is sufficiently loose to prevent the transmission of vibration to the ductwork. Duct turns andtransitions must be made carefully to hold the friction loss to a very minimum. Avoid short turns andduct elbows should contain splitters or turning vanes.

Ductwork which is connected to the fan discharge should run in a straight line at least 1½ fandiameters and should not be reduced in cross sectional area (See Figure 5). Figure 5 shows therecommended air discharge arrangement for an air duct turn made close to the unit. Notice that aduct should be in same direction as the fan rotation. Never deadhead the discharge into the flat sideof a plenum.

The air duct should never be unprotected to the elements when outside air is drawn into a unit. Ahood or louvered assembly should be provided to keep rain and snow out of the unit. Also anexpanded metal screen should be provided to keep birds and other animals out. Open return air ductsand free discharge openings should be protected with an expanded metal screen.

INSTALLATION

FIGURE 5: RECOMMENDED DISCHARGE DUCT ARRANGEMENT WHEN TURNSARE REQUIRED

NOTE : MAKE TURNS IN THE SAME DIRECTION AS FAN ROTATION.

FIGURE 6: DUCT CONNECTIONS

A

ROD

JACK SHAFTARM

JACK SHAFTARM

ROD

JACK SHAFT ARM

ROD

A

ROD

JACK SHAFTARM

B

B

INSTALLATION

DAMPER MOTORS AND LINKAGES

The face and bypass damper motors, as well as the zone damper motors, may be mounted on theunit.Prior to the installation of the electric or pneumatic operator motor, check the ease of operation ofthe damper blades while moving the operator arm back and forth by hand. If the vanes are difficultto turn, check to see that no material has been lodged in the assembly during shipment orinstallation. The rod between the operator and the operator arm of the vanes must always be at anangle of at least 40 degrees with respect to the operator arm to which it is attached. See Figure 7 . Ifnot, the operator motor will tend to push against the axle rather than provide the rotational motionnecessary to open and close the vanes. The travel of the operator motor arm should be adjusted sothat it is somewhat less than the travel of the arm on the damper axle. A pneumatic or electricoperator motor should never be adjusted so that a force is placed on the damper operator arm whenthe vanes are completely open or completely closed.

FIGURE 7: SETTING ZONE DAMPER RODS AND DAMPER LINKAGE

WRONG!ANGLE "A" LESS THAN 40°

CORRECTANGLE "B" LARGER THAN 40°

INSTALLATION

PHYSICAL DIMENSION

1.) HORIZONTAL TYPE

Note: For 2” panel add 2” at “A”, “C”, “D”. Add 2” at “B” for model up to 320 and 4” for model 420 onwards.Model 12 22 32 40 48 64 80 100 120 150 180 240 270 320 420 520 640

A 34 46 48 58 68 74 76 76 92 92 102 120 128 146 154 154 184B 49 50 54 60 60 62 66 66 66 70 78 86 86 86 122 122 126C 26 1/2 30 34 36 1/2 38 43 49 56 56 70 72 80 1/2 84 84 96 108 1/2 108 1/2D – – – – – – – – – – – – – – 86 86 90

2.) VERTICAL TYPE

Note: For 2” panel add 2” at “A”, “B”, “H1” and “H2”. Add 2” at “C” for model up to 48 and 4” for model 64 onwards.Model 12 22 32 40 48 64 80 100 120 150 180 240 270 320

A 34 46 48 58 68 74 76 76 92 92 102 120 128 146B 25 1/2 29 33 35 1/2 40 1/2 41 1/2 45 49 49 54 59 3/4 68 68 70C 52 57 67 72 73 84 1/2 94 105 105 124 131 3/4 150 1/2 154 159H1 – – – – – 41 1/2 45 49 49 54 59 3/4 70 70 75H2 – – – – – 43 49 56 56 70 72 80 1/2 84 84

3.) MULTIZONE TYPE

Note: For 2” panel add 2” at “A”, “D”, “E” and “H2”. Add 4” at “B”. Add 2” at “C” for model up to 120 and 4” for model 150 onwards. Add 2” at H1 formodel 150 onwards.

Model 22 32 40 48 64 80 100 120 150 180 240 270 320 420 520 640

A 46 48 58 68 74 84 84 100 100 120 120 128 146 154 154 184B 68 73 83 1/4 88 1/2 97 1/2 101 113 113 128 133 1/2 152 152 156 172 172 180C 47 52 54 1/2 56 65 71 80 80 98 100 112 1/2 116 124 133 1/2 156 1/2 156 1/2D 28 33 35 1/2 40 1/2 41 1/2 45 49 49 54 59 1/2 68 68 70 86 86 90E 40 40 48 48 56 56 64 64 74 74 84 84 86 86 86 90H1 18 18 18 18 22 22 24 24 28 28 32 32 40 40 48 48H2 29 34 36 1/2 38 43 49 56 56 70 72 80 1/2 84 84 93 1/2 108 1/2 108 1/2

Notes: 1.) All dimensions are in inches.2.) Spring type isolators are for standard fan of model AF 64 onwards and FS 80 onwards only, the rest will be rubber isolator mounting.3.) L/H motor and R/H piping shown.

B B

A A

B

B D

A

D BB

AA

B

A

A

B

A

B

A

E

E

E

E

A

B

INSTALLATION

PHYSICAL DIMENSION

4.) DIMENSIONS FOR ACCESSORY SECTIONSFAN ONLY COIL MODULE EXTERNAL FACE AND BYPASS

(See Note 4)INTERNAL FACE AND

BYPASS

STANDARD MIXING BOX COMB. ANGLE FILTER MIXING BOX ANGLE FILTER SECTION

BAG AND FLAT FILTER SECTION DIFFUSER SECTION SILENCER

Model 12 22 32 40 48 64 80 100 120 150 180 240 270 320 420 520 640

A 26 1/2 30 34 36 1/2 38 43 49 56 56 70 72 80 1/2 88 1/2 88 1/2 96 108 1/2 108 1/2

Fan Only 25 1/2 28 33 35 1/2 40 1/2 41 1/2 45 49 49 54 59 3/4 68 68 72 86 86 90

Coil Module 36 36 36 36 36 36 36 36 36 36 36 36 36 36 36 36 36

Face & ByPass -

External B 26 3/8 26 3/8 26 3/8 26 3/8 26 3/8 26 3/8 26 3/8 26 3/8 26 3/8 32 3/8 32 3/8 32 3/8 37 3/8 37 3/8 37 3/8 43 5/8 43 5/8

(Opposeddamper)

Internal B 6 6 6 8 8 8 8 8 8 8 8 10 10 10 10 10 10

Mixing Standard B 16 16 22 22 22 22 22 30 30 32 32 44 44 48 48 60 60

Box Comb. Filter B 24 24 32 32 32 36 36 40 40 44 44 48 48 56 60 72 72

(Parallerdamper)

DamperSection Width

E 8 8 14 14 14 14 14 22 22 24 24 36 36 40 40 52 52

DamperSection Length

15 27 22 28 33 44 55 44 53 60 72 64 72 77 101 96 119

Angle Filter B 22 22 22 22 22 22 22 22 22 22 22 24 24 24 24 24 24

Bag & Flat Filter Section B 30 30 30 30 30 30 30 30 30 32 32 36 36 36 36 36 36

Diffuser B 16 16 22 22 22 22 22 30 30 32 32 36 36 48 48 60 60

Silencer B 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40

Section Width 34 46 48 58 68 74 76 76 92 92 102 120 128 146 154 154 184

Notes: 1.) All dimensions are in inches.2.) For 2” panel add 2” at all dimensions. Except damper section width and length.3.) Consult factory for dimensions of energy recovery unit.4.) Bypass duct not included.

INSTALLATION

UNIT SHIPPING WEIGHTS (LBS)

Model Size 12 22 32 40 48 64 80 100 120 150 180 240 270 320 420 520 640

Basic Unit : FS Type

Single Horizontal 449 628 733 967 1022 1114 1470 1825 2039 2539 2910 3872 4140 4431 – – –

Skin Vertical 402 626 698 940 1040 1382 1636 2129 2549 2810 3690 4435 4850 5320 – – –

5R 12 FIN(See Note 3)

FanSection

239 402 466 590 592 677 947 1286 1380 1853 2097 2712 2890 3068 – – –

Double Horizontal 466 656 767 1001 1065 1190 1582 1939 2138 2653 3026 4005 4300 4598 – – –

Skin Vertical 404 663 737 998 1099 1453 1729 2248 2684 2969 3833 4592 5099 5610 – – –


FanSection

249 427 489 610 618 724 1020 1367 1450 1937 2181 2805 2990 3181 – – –

Basic Unit : AF Type

Single Horizontal – – – 1013 1132 1336 1622 1977 2241 2767 3159 4227 4791 5360 7163 8447 9193

Skin Vertical – – – 989 1140 1604 1788 2281 2751 3038 3939 4797 8632 6248 – – –


FanSection

– – – 636 692 899 1099 1438 1582 2081 2346 3848 3912 3997 5335 6330 6475

Double Horizontal – – – 1047 1165 1412 1734 2091 2340 2881 3295 4330 4890 5526 7665 8371 9400

Skin Vertical – – – 1045 1199 1675 1881 2400 2886 3197 4082 4954 5700 6547 – – –


FanSection

– – – 657 718 946 1172 1519 1652 2165 2430 3143 3632 4109 5709 6543 6621

Accessories

Diffuser Section 91 119 173 202 226 230 295 401 431 588 613 827 1015 1194 1303 1710 1865

Coil Module with DrainPan (without Coil)

146 209 260 326 364 395 476 481 517 735 844 1011 1102 1194 1303 1710 1865

External Face andBypass (without Duct)

71 91 93 106 119 146 187 217 233 337 350 628 683 690 820 835 912

Internal Face andBypass

11 21 26 30 41 53 64 80 96 119 146 189 221 254 321 364 444

Flat and Bag FilterSection (without Filters)

171 224 236 277 308 333 402 441 474 587 613 827 857 895 977 1026 1119

Angle Filter Section(without Filters)

125 164 173 202 225 244 294 323 347 404 423 552 575 597 651 684 746

Combination Mixingand Filter Section(without Filters)

137 179 251 294 328 364 482 535 574 808 844 1103 1233 1393 1629 2052 2237

Mixing Box 91 119 173 202 225 244 294 401 431 587 613 1011 1100 1194 1303 1710 1864

Silencer(Couple with Silencer)

200 263 277 325 360 390 470 517 555 881 920 1105 1142 1193 1302 1368 1492

3 Rows 34 47 56 66 77 94 109 129 149 185 227 284 322 361 423 470 555

Coil Only 4 Rows 39 51 65 78 91 112 130 154 180 224 275 346 395 444 523 583 693

@ 12FPI. 5 Rows 47 61 78 94 110 135 158 188 220 272 334 421 481 541 639 712 849

(See Note 4) 6 Rows 52 68 87 105 124 153 179 214 251 311 382 483 550 624 740 825 987

8 Rows 65 85 109 132 156 194 229 274 322 398 489 620 730 804 956 1067 1281

Cartridge Filter Box 45-95%

16 22 32 36 48 54 81 96 122 130 148 208 230 270 390 432 576

Notes: 1.) All basic units weight are based on maximum motor frame size.2.) Add 10 % for 2” panels.3.) All basic unit weight are based on 5R 12FPI coil, correct with “coil only weight” if actual data required.4.) For other fin series : “8FPI” x 0.85, “10FPI” x 0.92, “14FPI” x 1.08.

S3

P2QP1

R

S3

AIROUT

AIRIN R

S1

P1 Q P2

AIROUT

INAIR R

S1

P1 Q P2

AIRIN

OUTAIR

R

AIROUT

AIRIN

S2

P1 Q P2

RS1

P1 Q P2

R

P1 QP2

AIROUT

AIRIN

OUTAIR

AIRIN

P1 Q P2 QP1P2

P2QP1

RR

P1P2

AIRIN

AIRIN

AIRIN

AIROUT OUT

AIR

AIROUT OUT

AIR

S1

Q

S1

S4

R

S4

R

COMPONENTS ARRANGEMENT

DISCHARGE ARRANGEMENTS

A.) FAN SECTION ONLY

Horizontal Front Top Inverted Top

B.) SINGLE ZONE HORIZONTAL TYPE

Horizontal Front Top Inverted Top

C.) SINGLE ZONE VERTICAL TYPE

Horizontal Front Horizontal Rear Top Inverted Top

Forward Curved Blower Backward Inclined Airfoil Blower

Model P1 P2 Q R S1 S2 S3 S4Max.

MotorFrameSize

P1 P2 Q R S1 S2 S3 S4Max.

MotorFrameSize

12 9 15 7/8 9 1/8 10 3/8 4 3/16 9 5/8 11 15/16 4 3/16 D90L – – – – – – – – –

22 15 13/16 19 11/16 10 1/2 11 3/8 4 3/16 10 3/4 14 7/16 5 D100L – – – – – – – – –

32 15 11/16 20 11/16 12 1/4 13 1/2 4 3/16 11 3/4 15 1/2 4 7/8 D100L – – – – – – – – –

40 19 1/16 24 3/16 14 3/4 16 4 3/16 12 3/4 16 5/16 4 1/2 D112M 17 3/16 24 3/16 16 16 4 3/16 11 1/8 14 5/8 6 3/16 D112M

48 26 5/8 26 5/8 14 3/4 16 4 3/16 12 3/4 16 5/16 5 1/2 D132S 22 13/16 28 17 13/16 17 13/16 4 3/16 12 3/16 15 13/16 4 3/16 D132M

64 24 1/16 31 5/16 18 5/8 16 4 3/16 12 3/4 16 3/8 11 5/8 D132M 22 3/16 31 3/16 19 15/16 19 15/16 5 3/4 14 7/8 19 1/16 5 D132M80 20 13/16 33 3/16 22 19 5 3/4 16 1/2 19 7/8 7 7/8 D160M 20 7/16 33 3/16 22 3/8 22 3/8 5 3/4 16 20 3/16 4 9/16 D160M

100 20 7/16 33 3/16 22 3/8 22 3/8 5 3/4 16 20 1/8 9 D160M 13 5/8 37 1/4 25 1/8 25 1/8 5 3/4 16 13/16 21 1/16 5 1/16 D160M

120 28 1/4 38 5/8 25 1/8 25 1/8 5 3/4 16 3/4 21 5 3/8 D180M 29 5/8 37 1/4 25 1/8 25 1/8 5 3/4 16 13/16 21 1/16 5 1/16 D180M

150 23 5/8 40 1/4 28 1/8 28 1/8 5 3/4 18 3/16 22 3/8 5 7/8 D180M 26 5/8 37 1/4 28 1/8 28 1/8 5 3/4 18 1/4 22 1/2 5 5/8 D180M

180 29 1/2 44 3/8 28 1/8 28 1/8 5 3/4 18 3/16 22 3/8 11 7/8 D180L 30 13/16 39 11/16 31 1/2 31 1/2 5 3/4 19 7/8 25 3/8 5 1/8 D180L

240 44 1/4 44 1/4 31 1/2 31 1/2 6 1/4 20 5/16 26 1/4 15 7/8 D200L 42 5/16 42 5/16 35 3/8 35 3/8 6 1/4 22 3/16 28 3/16 9 11/16 D180L

270 46 5/16 46 5/16 35 3/8 35 3/8 6 1/4 22 1/8 28 10 1/8 D200L 46 5/16 46 5/16 35 3/8 35 3/8 6 1/4 22 3/16 28 3/16 9 11/16 D200L

320 53 3/16 53 3/16 39 5/8 39 5/8 4 3/16 24 7/16 28 3/4 10 D200L 53 3/16 53 3/16 39 5/8 39 5/8 4 3/16 22 7/16 29 7/16 9 3/16 D200L420 – – – – – – – – 54 3/4 54 3/4 44 1/2 44 1/2 4 3/16 24 5/8 31 11/16 – D250SC

520 – – – – – – – – – 52 1/16 52 1/16 49 7/8 49 7/8 4 3/16 25 5/8 32 11/16 – D250MC

640 – – – – – – – – – 64 64 56 56 4 3/16 28 5/16 35 5/16 – D280SC

Notes: 1.) P2 is motor location. P1 & P2 can be inter charged to switch motor location.2.) For other type of discharge arrangement, consult factory for dimensional details.3.) Dimensions shown are for 1” panel unit. For 2” panel - Add 1” at P1, P2, S1, S2, S3 (for 240 and above only) and S4 (for 64 and above only).

PANEL

LATCH

GASKET

FIBREGLASS

COLUMN

90°

FRAME


BLOWER ARRANGEMENTIt is important to study the site layout and select the type of blower discharge pattern to suit theductwork direction which will minimise noise and vibration. The selected blower discharge patternshould be specified in the purchase order (or order form) to the factory. Avoid field conversion ofblower discharge pattern. If field conversion of the blower discharge pattern is required, contactfactory or nearest Dunham-Bush representative and the field conversion should only carried outunder the supervision of a factory authorised personnel. Figures and table above (Page 16) give fandischarge arrangements and dimensions.

QUICK SERVICE ACCESS

Access panels are easily removable byturning door latch a quarter-turn and liftingoff the panel.

All access opening are lined with 1/8" thickneoprene gasket for airtight seal.

COIL SECTIONCoil sections are integral with fan section forstandard models up to size 180. For largermodels, separate coil modules are providedto enable direct coupling to fan section orconnection via flexible connectors, ifdesired.

As an option, coil modules can be furnishedwith extended space to accommodate pre-heat and/or reheat coils.

FIGURE 8: QUICK LATCH

DRAIN PANThe drain pan is designed to effectively collect all the condensate and drain on either or both sides of theunit. The pan is of double-skinned sandwiched construction using heavy gauge galvanised steel withfiberglass in between. Option is available for stainless steel drain pan and other types of insulationmaterial.

COILStandard coils are suitable for 250 psig working pressure and are tested under water with 350 psig airpressure. Following are also available as options for special applications:* 318", 5/8" or 3/4" OD copper tubes - coils.* Copper fins or tinned copper fins - coils* Higher design working and test pressures* Custom made coils for heating or cooling* Direct-expansion coils air-cooled condensers or evaporators


Table 6: Minimum– Maximum Airflow (Cfms)– For Cooling OnlyModel Size 12 22 32 40 48 64 80 100 120 150 180 240 270 320 420 520 640

Full CoilF.A.(ft²)

2.5 5.0 6.6 8.3 10.1 13.1 16.1 19.4 23.8 30.3 35.8 46.9 54.4 63.2 75.6 89.7 109.5

No. Of CoilTH x FL

112x24

116x36

120x38

120x48

120x58

126x58

130x62

136x62

136x76

146x76

148x86

226x104

228x112

228x130

232x136

238x136

238x166

Min. CFM 750 1500 1980 2490 3030 3930 4740 5820 6990 8760 10830 14070 16260 18750 22680 26910 32850

Max. CFM 1500 3000 3960 4980 6060 7860 9480 11640 13980 17520 21660 28140 32520 37500 45360 53820 65700

Notes: 1. All coils performance are based on standard face area with nominal airflow and 12FPI for model 12 to 150. 10 FPI formodel 180 to 640.

2. Water coils 44°F EWT and 10°F WTR temperature rise.3. DX coils are R22 @ 40°F SST.4. Since the final coil selection will seldom be at the above conditions, we recommend you refer to the Dunham-Bush

Sales & Services computer coil program for all final coil selections.

FAN SECTION

FAN TYPES

Forward curved, or backwardinclined airfoil fans can be providedto suit the required applications.Forward curved wheels areconstructed of galvanised steel andare tested in accordance with ARIStandard 430, suitable for externalstatic pressure up to 5" w.g.Backward inclined wheels are ofeither aluminium or steelconstruction, wide structuralmembers to provide maximumrigidity and are tested in accordancewith ARI Standard 430, and suitablefor external static pressure up to 6" w.g. Backward inclined airfoils wheels are of non-overloadingcharacteristics. All fans are statically and dynamically balanced.

MOTOR LOCATIONThere are two possibility ofarrangements: on the left or rightof the blower section. Unlessotherwise specified to factory, themotor location provided is at theopposite side to the chilled waterand drain piping connection(access panel will be done tofacilitate service).

FIGURE 10: PLAN VIEW OF DISCHARGE

Air Foil Fan Wheel (AF)Forward Curved Fan Wheel (FS)

HUMIDIFIERSECTION

MIXING BOXSECTION

PREHEATCOIL

BAG FILTERSECTION REHEAT

COILELIMINATOR

SPRINGISOLATORS

DIFFUSERPLATE

COOLINGCOIL

ZONEDAMPERS

UNIT FEATURES AND ACCESSORIES

UNIT ASSEMBLY PLANNING

The Dunham-Bush modular central station air-handling units are available for draw-throughapplication.

Draw through air-handling units are available for low, medium or high pressure single zoneapplications in horizontal or vertical arrangement, for ceiling or floor mounting.

Blow-through air handlers are available for multi-zone and single zone applications in horizontalarrangements for low, medium and high pressure applications.

TYPICAL ARRANGEMENT

FIGURE 11: MULTI-ZONE AIR-HANDING UNIT

UNIT FEATURES AND ACCESSORIES

FAN BEARINGS

Fan bearings are of the self-aligning with regreasable ball bearings and selected for. minimum 100,000operating hours.

VIBRATION ISOLATION

Spring isolators are standard for unit with internally mounted motor to provide excellent vibrationisolation. For unit with externally mounted motor and drive package, external spring isolators orneoprene Pads are provided to isolate complete air handling unit.

Fan and motor of standard unit are mounted on the same rigid, rugged steel frame.

Fan discharge is connected to unit discharge by internal flexible duct connectors to further reducevibration of unit.

FIGURE 12: VIBRATION ISOLATION AND DISCHARGE CONNECTION

OPERATION

PRE-OPERATION CHECK( 1.) Is the blower pulley properly mounted onto shaft.( 2.) Is the motor rotation direction correct.( 3.) Is belt tension normal and belt size correct.( 4.) Are all bolts and nuts properly tightened.( 5.) Is the belt adjustment normal.( 6.) Is motorised damper functioning.( 7.) Is thermostat, fan selector switch functioning.( 8.) Is 3 or 4 way valve in proper condition.( 9.) Are the air filters in place.( 10.) Is fan wheel able to rotate free and clear when it is manually rotated.( 11.) Is fan and motor bearings properly lubricated.( 12.) Check that the fan and motor bearings do not run hot.( 13.) Is insulation properly done.

After the unit has been operated for quite sometime, do the following running check:

( 1.) Is fan rpm and rotation correct.( 2.) Is motor running amps within the full load ampere.( 3.) Is motor and fan getting too hot.( 4.) Is there any air leakage from unit.( 5.) Is the unit panel and fan housing sweating.( 6.) Chilled water temperature inlet and outlet.( 7.) Inlet and outlet chilled water pressure.( 8.) Is unit vibrating excessively.( 9.) Is the on/off design coil temperature being achieved by the units.

Take necessary action to rectify any abnormal, operating conditions. Contact Dunham-Bush office for anyuncertainties.

PRESSURE DROPSTABLE 7: CASING AND FILTERS ("WG)

SECTION STANDARD COIL FACE VELOCITY (FPM)

300 400 500 600

BASIC UNIT (VERT.) NO. COIL 0.100 0.170 0.260 0.360

FACE AND BYPASS 0.020 0.040 0.060 0.100

MIXING BOX WITH FILTERS T.A. 0.059 0.090 0.125 0.163

MIXING BOX WITH CLEANABLE 0.030 0.053 0.073 0.088

FLAT FILTER (HI-VEL) CLEAN 0.028 0.055 0.087 0.114

V-TYPE FILTER (LO-VEL) T.A. 0.040 0.060 0.080 0.130

V-TYPE FILTER CLEAN 0.011 0.023 0.028 0.055

ELIMINATOR ASSEMBLY 0.024 0.039 0.057 0.077

TABLE 8: AIR SIDE PRESSURE LOSS ("WG)FACE VEL HOT WATER, STANDARD STEAM NON- FREEZE STEAM CHILLED WATER, DX

(FPM) 1 ROW(DRY) 2 ROW(DRY) 1 ROW(DRY) 2 ROW(DRY) 4 ROW(WET) 6 ROW(WET) 8 ROW(WET)

350 0.035 0.075 0.046 0.082 0.304 0.456 0.604

400 0.047 0.097 0.056 0.103 0.376 0.564 0.752

450 0.059 0.125 0.071 0.128 0.452 0.678 0.904

500 0.073 0.150 0.083 0.154 0.536 0.804 1.072

550 0.088 0.185 0.102 0.184 0.620 0.930 1.240

600 0.105 0.220 0.115 0.215 0.712 1.068 1.424

650 0.125 0.260 0.137 0.247 0.800 1.200 1.600

700 0.143 0.300 0.153 0.281 0.908 1.362 1.816

NOTE: 8 FINS/ INCH.

OPERATION LIMITATION

In order for the units to perform smoothly and be long lasting, the following operating limitation has tobe strictly abided to:

TABLE 9

MODEL MIN CFM MAX CFM MAX MOTOR FRAME SIZE

FS AF

12 750 1500 D90L -

22 1500 3000 D100L -

32 1980 3960 D100L -

40 2490 5980 D112M D112M

48 3030 6060 D112M D132M

64 3930 7860 D132M D132M

80 4740 9480 D160M D160M

100 5820 11640 D160L D160L

120 6990 13980 D160L D160L

150 8760 17520 D180M D180M

180 10830 21660 D180L D180L

240 14070 28140 D200L D180L

320 17490 34980 D200L D200L

420 21240 42480 - D250SC

520 26910 53820 - D250MC

640 32850 65700 - D280SC

MAINTENANCE

An air handling unit, as with any mechanical equipment, requires periodic maintenance. The following isa recommended "check list" to be used as a guide in establishing a maintenance program.

PERIODIC INSPECTION( 1.) Check the fan motor and fan shaft to see that they are adequately lubricated. The shaft bearings are

prefabricated and Zerk fittings are factory installed for relubrication. Shaft bearings should normallybe relubricated once a year as a minimum for applications where the units operate in a generallyclean, dry atmosphere. Bearings in units for outdoor or industrial applications may requirerelubrication two or three times a year or as often as once a month for severe conditions.Lubrication should be done when unit is not running and by means of a hand grease gun until greasegoes through the bearing so that a bead of grease appears at the sear lip contacts. The mostimportant time for lubrication is before any prolonged storage or shutdown to flush out any foreignmaterial and to prevent moisture from entering the bearing. The recommended grease is lithiumbase water resistant type such as Albania No. 3 by Shell Oil Company or its equivalent.The fan motor should be lubricated in accordance with manufacturer's recommendation orapproximately every 5 years.Caution should be exercised when lubricating bearings to be sure that no foreign matter gets intobearings.

( 2.) Check the belts for proper tension and alignment at least once every six months. Proper belt tensiondepends on the center distance between pulleys and type of belt used.

( 3.) Check the pulleys and sheaves at least once every six months to make certain that set screws areproperly tightened.

( 4.) To insure proper air cleaning efficiency, filters must be properly maintained. Dirty filters willreduce the air volume handled by the unit which will result in reduced unit capacity. The length oftime between the replacement of throwaway filters or cleaning of permanent type filters isdependent upon the condition of the circulated air. A six week cycle is normal, however, morefrequent servicing may be required.

ANNUAL INSPECTION( 1.) If the unit is painted, check for evidence of corrosion or peeling. These areas should be properly

cleaned and retouched.( 2.) Tighten the blower wheel set screws. Inspect the wheels and housings for evidence of corrosion and

retouch if necessary.( 3.) Wash down the coil fin surfaces to eliminate dirt, lint or other foreign matter. If there is a

particularly heavy accumulation of material, more frequent replacement or cleaning of filters isindicated.

( 4.) Check the motor and fan shaft bearings for evidence of wear.( 5.) Check the drain pan and drain line to see that condensate is being properly drained and there are no

restrictions in the line.( 6.) Replace all belts showing evidence of wear.( 7.) When cleanable type water coils are supplied, drain the water from the coils and remove several

plugs from the return bends. Inspect the tubes carefully and if there is any evidence of scaleformation, then remove all the plugs and clean the tubes. If chemicals are used for the cleaningoperation it is recommended that a reputable water treatment firm be contacted for arecommendation of the proper cleaning agent to be used.

NOTE: It is recommended that all units be rebalanced to a minimum of "Quality Grade G6.3" if shaft orwheel is replaced.

TROUBLESHOOTING CHART

SYMPTOM SOURCE PROBABLE CAUSE

Noise 1. Impeller hitting inletring

♦ Impeller not center (check shaft clamp).♦ Inlet ring damaged or not adjusted.♦ Shaft loose in bearing (check locking collar).♦ Impeller loose on shaft (check shaft clamp).♦ Bearing loose in bearing support (check mounting bolts).

2. Drive ♦ Sheave not tight on shaft (motor or fan).♦ Belts hitting belt guard.♦ Belts loose. Adjust after 48 hours operation.♦ Belts too tight.♦ Belts wrong cross section.♦ Belts not "match" in length on multi-belt drive Variable

pitch sleaves not adjusted so each. groove has same pitchdiameter (multi-belt drives).

♦ Misaligned sheaves.♦ Belts worn.♦ Motor, motor base or fan not securely anchored.

Belts oily or dirty.

3. Bearing ♦ Defective bearing.♦ Needs lubrication.♦ Loose on bearing support.♦ Loose on shaft (check locking collar).♦ Misalignment (check alignment binding).♦ Worn bearing♦ Fretting corrosion between inner race and shaft.

4. Impeller ♦ Loose on shaft (check shaft clamp).♦ Defective impeller. Do not run fan. Contact manufacturer.♦ Unbalance.♦ Foreign material on fan blades.

5. Housing ♦ Foreign material in housing.♦ Inlet cones loose or not adjusted.

6. Electrical ♦ Lead-in cantle not secure or is too rigid.♦ AC hum in motor or relay.♦ Starting relay chatter.♦ Motor bearings.♦ Single phasing a 3-phase motor.

7. Shaft ♦ Bent.♦ Undersized. May caused noise at impeller, bearings or

sheave.♦ Loose internal balance weights.♦ Bearing alignment.

8. High air velocity ♦ Ductwork too small.♦ Fan running too fast.♦ Fan section too small.♦ Static pressure lower the expected.♦ Registers and grilles too small.♦ Insufficient face area of heating or cooling coil.



Noise 9. Obstruction in highvelocity air streammay cause rattle orpure tone whistle

♦ Dampers.♦ Registers.♦ Loose dampers or splitters.♦ Grilles.♦ Sharp elbows.♦ Sudden expansion of duct work.♦ Sudden contraction of ductwork.♦ Turning vanes.

10.Pulsation or surge ♦ Oversize ductwork.♦ Parallel fan operation.♦ Loose dampers or splitters.♦ System instability.♦ Ducts vibrate at same frequency as fan pulsations.♦ Organ pipe action on long duct.

11.High velocity throughcracks holes or pastobstructions

♦ Leaks in duct work.♦ Registers or grilles.

12.Rattles and/or rumbles ♦ Excessive duct velocities.♦ Vibrating ductwork.♦ Flex connector too tight or touching.♦ Vibrating cabinet parts.♦ Vibrating parts not isolated from building.

CFM low 1. Fan ♦ Forward curve impeller installed backward.♦ Fan running backward.♦ Impeller not centered with inlet cones.♦ Fan speed too slow.

2. Duct system ♦ Actual system is more restrictive (more resistance to flow)than expected.

♦ Dampers closed. Splitter rod disconnected.♦ Registers closed.♦ Leaks in supply ducts.♦ Open duct seams.♦ Insulating duct liner loose.♦ Fire dampers closed.

3. Filters ♦ Dirty clogged (dirt, lint, snow, grass)

4. Coils ♦ Dirty or clogged (construction trash)

5. Recirculation ♦ Internal cabinet leaks in bulkhead separating fan outlet(pressure zone) from fan inlets (suction zone).

♦ Leaks around fan outlet at connection through cabinetbulkhead.



CFM low 6. Obstructed fan inlets ♦ Elbows, cabinet walls or other obstructions restrict air flow.♦ Inlet obstructions cause restrictive systems but do not cause

increased negative pressure readings near the fan inlet(s).♦ Fan speed may be increased to counteract the effect of

restricted fan inlet(s).(observe fan RPM limits).

7. No straight duct at fanoutlet

♦ Fans which are normally used in duct systems are testedwith a length of straight duct at the fan outlet. If there is nostraight duct at the fan outlet, decreased performance willresult. If it is not practical to install a straight section ofduct at the fan outlet the fan speed may be increased toovercome this pressure loss. Observe fan RPM limits.

8. Obstructions in highvelocity air stream

♦ Obstruction near fan outlet.♦ Sharp elbows near fan outlet.♦ Improperly designed or no turning vanes.♦ Projections, dampers or other obstructions in part of system

where air velocity is high.

CFM high 1. System ♦ Oversized ductwork.♦ Access door open.

♦ System not balanced. Resistance less than specified.

♦ Registers or grilles not installed.

♦ Dampers set to bypass coils.

♦ Filter(s) not in place.

2. Fan ♦ Backward inclined impeller installed backward (HP will behigh).

♦ Variable motor sheave not adjusted.

♦ Fan speed too fast.

StaticPressureIncorrect

1. System fan orinterpretation ofmeasurements

♦ General Discussion:♦ The velocity pressure at any point of measurement is a

function of the velocity of the air and its density.♦ The static pressure at a point of measurement in the system

is a function of system design (resistance to flow), airdensity and the amount of air flowing through the system.

♦ The static pressure measured in a "loose" or oversizedsystem will be less than the static pressure in a "tight orundersized system for the same airflow rate.

♦ In most systems, pressure measurements are indicators ofhow the installation is operating. These measurements arethe result of airflow and such are useful indicators indefining system characteristics.

2. System ♦ System has less resistance to flow than expected. This is acommon occurrence. Fan speed may be reduced to obtaindesire flow rate. This will reduce HP, conserve energy,and save operating costs.

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