INSTALLATION OPERATION AND MAINTENANCE MANUAL FORM NO: MM0101B Products That Perform...By People Who Care Central Station Air-Handling Units MODELS: *AHFS *AHAF *AHBF *AHDFS *AHDAF *AHDBF
TABLE OF CONTENTS SECTION PAGE NOMENCLATURE... 3 INTRODUCTION GENERAL... 4 RECEIVING... 4 HANDLING AND RIGGING... 5 STORAGE... 5 INSTALLATION LEVELING FAN DECK ASSEMBLY... 6 CLEARANCE... 6 GENERAL PIPING PARAMETERS- HOT WATER COILS... 7 STEAM COILS... 8 DIRECT EXPANSION COILS... 9 BELT AND SHEAVES... 9 CONDENSATE DRAIN TRAPS... 10 DUCT CONNECTIONS... 11 DAMPER MOTORS AND LINKAGES... 12 PHYSICAL DIMENSION... 13 UNIT SHIPPING WEIGHTS (LBS)... 14 COMPONENTS ARRANGEMENT DISCHARGE ARRANGEMENTS... 16 BLOWER ARRANGEMENT... 16 QUICK SERVICE ACCESS... 18 COIL SECTION... 18 FAN SECTION... 19 MOTOR LOCATION... 19 UNIT FEATURES AND ACCESSORIES UNIT ASSEMBLY PLANNING... 20 TYPICAL ARRANGEMENT... 20 FAN BEARINGS... 21 VIBRATION ISOLATION... 21 OPERATION PRE-OPERATION CHECK... 22 PRESSURE DROPS... 22 OPERATING LIMITATION... 23 MAINTENANCE PERIODIC INSPECTION... 24 ANNUAL 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 AH= Air Handler Single Skinned AHD= Air Handler Double Skinned L= Low Pressure Unit Up To 3.5 TSP M= Medium Pressure Unit Over 3.5 TSP FS= AF= BF= Forward Curved Wheel Air Foil Wheel Backward Curved Unit Size = Nominal CFM 100 H= Horizontal V= Vertical M= Multi Zone MODULAR DESIGN RETURN FAN SECTION ECONOMIZER PREFILTER, COOLING COIL AND SUPPLY FAN SECTION BAG FILTER SECTION DISCHARGE DAMPER
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 to ensure lower first cost, longer equipment life and high overall operating efficiency. Dunham-Bush central station air-handling units are designed for cooling, dehumidifying (or humidifying), heating, ventilating and filtering. It is best suited for high-rise buildings, big industrial plants, hospitals, shopping centres, computer rooms and many other centralised systems. Its sectionalised design enable full lines of accessories to be attached to accommodate various applications. Every air-handlers is designed and tested by experienced engineers. It is fabricated with rigid galvanised steel frame work and thick gauge galvanised steel panel for rugged handling operation. It is 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-Bush office immediately. Carefully inspect all shipments immediately after delivery. When damage is evident, note this fact on 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 loss can 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 you have thoroughly checked the units because bolts, belts or other small item's might be packed inside the 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 are shipped in a few sections or completely knock-down. Care is required in handling the individual parts. 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 destroy permanently the value of the protective covering for the metal. Any such rupture of coating, due to mishandling, is not covered by the guarantee. Air handling units are shipped on strong plastic package or crate with sections bolted as determined by 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 any sections. Check the weight of the units before rigging. Try to place the rigging cable such that the weight is evenly distributed. Lifting cables should not be attached to the extremities of the accessory sections without intermediate 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 load should be avoided. On no occasion should anything be stacked on top of the units. The elapsed time for 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 minimum foundation shall be 4 times the rotating mass of the fan and drives or about double of the units weight). Refer to table 1 to 5 for weight and dimensions. ( 2.) Is there sufficient space for making piping, drainings and wiring connections, and this space accessible. ( 3.) Is there adequate space for servicing the unit, and for removing or opening the access doors. A minimum clearance equal to the width of the units must be provided on one side of the unit for removing 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-conditioner which can adversely affect any other nearby equipment, it is recommended that either one of the following 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 engineering practice has to be applied. Ideally, a heavy concrete slab should be used for floor mounted units, and main support beams for ceiling hung units. Long floor or ceiling spans should be avoided. LEVELING FAN DECK ASSEMBLY After installation, check the fan deck to ensure that it is level with the foundation. The level may be corrected by loosening the cap screw (see Figure 1). To raise the level, turn the adjusting screw anti-clockwise; to lower, turn the screw clockwise. When the correct level is achieved, firmly tighten the cap screw. FIGURE 1: SPRING FLOOR MOUNT 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 Curb mounted and weather-proof units can be provided upon request.
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 the coil. 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 automatically proportioning the amount of water flowing through the coil or through the by-pass. The water flow is regulated by a motorised 3 way mixing valve, controlled through a proportional remote bulb temperature controller. ( 5.) A gate valve and hose connection provided in the supply line dirt leg should be supplied when floor 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 VENT PROPORTIONAL REMOTE BULB TEMP. CONTROL 3 WAY MIXING VALVE RETURN GATE VALVE SUPPLY GAGE COCK PLUG COCK THERMOMETER DIRTLEG WITH GATE VALVE (7/8"OD MIN.)
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 supply connection 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 temperature drops 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 COILS Each coil must be installed with the suction header on the entering air face of the coil and with the suction connection at the lower end. The orientation of the refrigerant distributor is not critical but the 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 which contains a header suction connection. If the air flow through two or more coils is in parallel, as in a stacked coil bank, the suction piping must be installed in such a way that liquid from one coil suction header cannot reach another coil suction header. The bulb for the control valve must be attached 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 are Figure 4: DX Coil Piping Arrangement connected to a common suction line, never place the bulb on the common line. Thermostatic expansion valves are to be equipped with external equalizer tubes that are field connected to the suction line. The valve should be sized in accordance with the manufacturers recommendations, allowing approximately 35 psi pressure drop through the coil and distributor at full load. Do not oversize the valve. Follow the valve manufacturer's instructions on the location of the thermostatic bulb. Proper expansion valve operation is necessary in order to realize the rated coil capacity. When a DX type coil is operated with a suction temperature below 32 F, a build up of frost will occur on the finned surface. It is, therefore, not recommended to operate DX coils for air conditioning purposes at below freezing suction temperatures. If the full load operating point for the coil is selected at a "safe" temperature, a system analysis is required to check for the lowest probable suction temperature at light load conditions. Suction pressure controlled hot gas bypass valves are available 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 as well as shortened belt and bearing life. It is important to install the fan sheave as close as practical to the bearing. Adjust the motor sheave to align with the fan sheave with the use of a straight edge. For multiple groove sheaves use the center groove of the motor sheave and align this center groove with the 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.
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 at operating conditions. b.) On blow-through units (A) can be as small as 1 but (B) must equal or exceed the total static pressure in the coil section. FIGURE 4: TYPICAL CONDENSATE PIPING SIDE VIEW OF 'AH' DRAIN PAN SLOPED TO DRAIN A DRAIN LINE SLOPED 1/4" MIN PER FT B TO DRAIN DUCT CONNECTIONS All intake and discharge air duct connections to the unit should be made with flexible material. The accessory flexible connectors may be used for this purpose. The flexible material should be installed so that it is sufficiently loose to prevent the transmission of vibration to the ductwork. Duct turns and transitions must be made carefully to hold the friction loss to a very minimum. Avoid short turns and duct elbows should contain splitters or turning vanes. Ductwork which is connected to the fan discharge should run in a straight line at least 1½ fan diameters and should not be reduced in cross sectional area (See Figure 5). Figure 5 shows the recommended air discharge arrangement for an air duct turn made close to the unit. Notice that a duct should be in same direction as the fan rotation. Never deadhead the discharge into the flat side of a plenum. The air duct should never be unprotected to the elements when outside air is drawn into a unit. A hood or louvered assembly should be provided to keep rain and snow out of the unit. Also an expanded metal screen should be provided to keep birds and other animals out. Open return air ducts and free discharge openings should be protected with an expanded metal screen.
INSTALLATION FIGURE 5: RECOMMENDED DISCHARGE DUCT ARRANGEMENT WHEN TURNS ARE REQUIRED NOTE : MAKE TURNS IN THE SAME DIRECTION AS FAN ROTATION. FIGURE 6: DUCT CONNECTIONS
INSTALLATION DAMPER MOTORS AND LINKAGES The face and bypass damper motors, as well as the zone damper motors, may be mounted on the unit. Prior to the installation of the electric or pneumatic operator motor, check the ease of operation of the damper blades while moving the operator arm back and forth by hand. If the vanes are difficult to turn, check to see that no material has been lodged in the assembly during shipment or installation. The rod between the operator and the operator arm of the vanes must always be at an angle of at least 40 degrees with respect to the operator arm to which it is attached. See Figure 7. If not, the operator motor will tend to push against the axle rather than provide the rotational motion necessary to open and close the vanes. The travel of the operator motor arm should be adjusted so that it is somewhat less than the travel of the arm on the damper axle. A pneumatic or electric operator motor should never be adjusted so that a force is placed on the damper operator arm when the vanes are completely open or completely closed. FIGURE 7: SETTING ZONE DAMPER RODS AND DAMPER LINKAGE WRONG! ANGLE "A" LESS THAN 40 ROD A JACK SHAFT ARM JACK SHAFT ARM A ROD CORRECT ANGLE "B" LARGER THAN 40 ROD B JACK SHAFT ARM B JACK SHAFT ARM ROD
INSTALLATION PHYSICAL DIMENSION 1.) HORIZONTAL T YPE 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 92 102 120 128 146 154 154 184 B 49 50 54 60 60 62 66 66 66 70 78 86 86 86 122 122 126 C 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 1/2 D 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 92 102 120 128 146 B 25 1/2 29 33 35 1/2 40 1/2 41 1/2 45 49 49 54 59 3/4 68 68 70 C 52 57 67 72 73 84 1/2 94 105 105 124 131 3/4 150 1/2 154 159 H1 41 1/2 45 49 49 54 59 3/4 70 70 75 H2 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 for model 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 84 100 100 120 120 128 146 154 154 184 B 68 73 83 1/4 88 1/2 97 1/2 101 113 113 128 133 1/2 152 152 156 172 172 180 C 47 52 54 1/2 56 65 71 80 80 98 100 112 1/2 116 124 133 1/2 156 1/2 156 1/2 D 28 33 35 1/2 40 1/2 41 1/2 45 49 49 54 59 1/2 68 68 70 86 86 90 E 40 40 48 48 56 56 64 64 74 74 84 84 86 86 86 90 H1 18 18 18 18 22 22 24 24 28 28 32 32 40 40 48 48 H2 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.
INSTALLATION PHYSICAL DIMENSION 4.) DIMENSIONS FOR ACCESSORY SECTIONS FAN ONLY COIL MODULE EXTERNAL FACE AND BYPASS (See Note 4) INTERNAL FACE AND BYPASS B B B A A A A STANDARD MIXING BOX COMB. ANGLE FILTER MIXING BOX ANGLE FILTER SECTION B B E D D B E B E A E A A BAG AND FLAT FILTER SECTION DIFFUSER SECTION SILENCER B B B A A A 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 & By 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 Pass - (Opposed damper) 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 (Paraller damper) Damper Section Width E 8 8 14 14 14 14 14 22 22 24 24 36 36 40 40 52 52 Damper Section 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) Fan Section 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 5R 12 FIN (See Note 3) Fan Section 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 5R 12 FIN (See Note 3) Fan Section 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 5R 12 FIN (See Note 3) Fan Section 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 Drain Pan (without Coil) External Face and Bypass (without Duct) Internal Face and Bypass Flat and Bag Filter Section (without Filters) Angle Filter Section (without Filters) Combination Mixing and Filter Section (without Filters) 146 209 260 326 364 395 476 481 517 735 844 1011 1102 1194 1303 1710 1865 71 91 93 106 119 146 187 217 233 337 350 628 683 690 820 835 912 11 21 26 30 41 53 64 80 96 119 146 189 221 254 321 364 444 171 224 236 277 308 333 402 441 474 587 613 827 857 895 977 1026 1119 125 164 173 202 225 244 294 323 347 404 423 552 575 597 651 684 746 137 179 251 294 328 364 482 535 574 808 844 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.
COMPONENTS ARRANGEMENT DISCHARGE ARRANGEMENTS A.) FAN SECTION ONLY R S3 P1 OUT Q P2 IN OUT P1 S1 Q R P2 IN OUT P1 Q R P2 IN S1 Horizontal Front Top Inverted Top B.) SINGLE ZONE HORIZONTAL TYPE R S3 P1 OUT Q P2 IN OUT S1 P1 R Q P2 IN OUT S2 P1 Q R P2 IN Horizontal Front Top Inverted Top C.) SINGLE ZONE VERTICAL TYPE S4 R P1 OUT Q P2 S4 R P1 OUT Q P2 OUT P1 Q R S1 P2 OUT P1 Q R P2 S1 IN IN IN Model Horizontal Front Horizontal Rear Top Inverted Top Forward Curved Blower P1 P2 Q R S1 S2 S3 S4 Max. Motor Frame Size Backward Inclined Airfoil Blower P1 P2 Q R S1 S2 S3 S4 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 D132M 80 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 D200L 420 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). Max. Motor Frame Size
COMPONENTS ARRANGEMENT BLOWER ARRANGEMENT It is important to study the site layout and select the type of blower discharge pattern to suit the ductwork direction which will minimise noise and vibration. The selected blower discharge pattern should be specified in the purchase order (or order form) to the factory. Avoid field conversion of blower discharge pattern. If field conversion of the blower discharge pattern is required, contact factory or nearest Dunham-Bush representative and the field conversion should only carried out under the supervision of a factory authorised personnel. Figures and table above (Page 16) give fan discharge arrangements and dimensions. QUICK SERVICE ACCESS Access panels are easily removable by turning door latch a quarter-turn and lifting off the panel. All access opening are lined with 1/8" thick neoprene gasket for airtight seal. FIGURE 8: QUICK LATCH FIBREGLASS GASKET PANEL LATCH COIL SECTION Coil sections are integral with fan section for standard models up to size 180. For larger models, separate coil modules are provided to enable direct coupling to fan section or connection via flexible connectors, if desired. As an option, coil modules can be furnished with extended space to accommodate preheat and/or reheat coils. COLUMN FRAME 90 DRAIN PAN The drain pan is designed to effectively collect all the condensate and drain on either or both sides of the unit. The pan is of double-skinned sandwiched construction using heavy gauge galvanised steel with fiberglass in between. Option is available for stainless steel drain pan and other types of insulation material. COIL Standard coils are suitable for 250 psig working pressure and are tested under water with 350 psig air pressure. 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
COMPONENTS ARRANGEMENT Table 6: Minimum Maximum Airflow (Cfms) For Cooling Only Model Size 12 22 32 40 48 64 80 100 120 150 180 240 270 320 420 520 640 Full Coil F.A.(ft²) No. Of Coil TH x FL 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 1 12x24 1 16x36 1 20x38 1 20x48 1 20x58 1 26x58 1 30x62 1 36x62 1 36x76 1 46x76 1 48x86 2 26x104 2 28x112 2 28x130 2 32x136 2 38x136 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: 2 38x166 1. All coils performance are based on standard face area with nominal airflow and 12FPI for model 12 to 150. 10 FPI for model 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 backward Forward Curved Fan Wheel (FS) Air Foil Fan Wheel (AF) inclined airfoil fans can be provided to suit the required applications. Forward curved wheels are constructed of galvanised steel and are tested in accordance with ARI Standard 430, suitable for external static pressure up to 5" w.g. Backward inclined wheels are of either aluminium or steel construction, wide structural members to provide maximum rigidity and are tested in accordance with ARI Standard 430, and suitable for external static pressure up to 6" w.g. Backward inclined airfoils wheels are of non-overloading characteristics. All fans are statically and dynamically balanced. MOTOR LOCATION There are two possibility of arrangements: on the left or right of the blower section. Unless otherwise specified to factory, the motor location provided is at the opposite side to the chilled water and drain piping connection (access panel will be done to facilitate service). FIGURE 10: PLAN VIEW OF DISCHARGE
UNIT FEATURES AND ACCESSORIES UNIT ASSEMBLY PLANNING The Dunham-Bush modular central station air-handling units are available for draw-through application. Draw through air-handling units are available for low, medium or high pressure single zone applications in horizontal or vertical arrangement, for ceiling or floor mounting. Blow-through air handlers are available for multi-zone and single zone applications in horizontal arrangements for low, medium and high pressure applications. TYPICAL ARRANGEMENT FIGURE 11: MULTI-ZONE -HANDING UNIT BAG FILTER SECTION ELIMINATOR REHEAT COIL MIXING BOX SECTION PREHEAT COIL HUMIDIFIER SECTION SPRING ISOLATORS DIFFUSER PLATE COOLING COIL ZONE DAMPERS
UNIT FEATURES AND ACCESSORIES FAN BEARINGS Fan bearings are of the self-aligning with regreasable ball bearings and selected for. minimum 100,000 operating hours. VIBRATION ISOLATION Spring isolators are standard for unit with internally mounted motor to provide excellent vibration isolation. For unit with externally mounted motor and drive package, external spring isolators or neoprene 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 reduce vibration 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 any uncertainties. PRESSURE DROPS TABLE 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: 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 to be 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 is a 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 normally be relubricated once a year as a minimum for applications where the units operate in a generally clean, dry atmosphere. Bearings in units for outdoor or industrial applications may require relubrication 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 grease goes through the bearing so that a bead of grease appears at the sear lip contacts. The most important time for lubrication is before any prolonged storage or shutdown to flush out any foreign material and to prevent moisture from entering the bearing. The recommended grease is lithium base 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 or approximately every 5 years. Caution should be exercised when lubricating bearings to be sure that no foreign matter gets into bearings. ( 2.) Check the belts for proper tension and alignment at least once every six months. Proper belt tension depends 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 are properly tightened. ( 4.) To insure proper air cleaning efficiency, filters must be properly maintained. Dirty filters will reduce the air volume handled by the unit which will result in reduced unit capacity. The length of time between the replacement of throwaway filters or cleaning of permanent type filters is dependent upon the condition of the circulated air. A six week cycle is normal, however, more frequent 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 is indicated. ( 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 scale formation, then remove all the plugs and clean the tubes. If chemicals are used for the cleaning operation it is recommended that a reputable water treatment firm be contacted for a recommendation 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 or wheel is replaced.
TROUBLESHOOTING CHART SYMPTOM SOURCE PROBABLE CAUSE Noise 1. Impeller hitting inlet ring 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 pitch diameter (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.
TROUBLESHOOTING CHART SYMPTOM SOURCE PROBABLE CAUSE Noise 9. Obstruction in high velocity air stream may cause rattle or pure tone whistle 10.Pulsation or surge 11.High velocity through cracks holes or past obstructions 12.Rattles and/or rumbles Dampers. Registers. Loose dampers or splitters. Grilles. Sharp elbows. Sudden expansion of duct work. Sudden contraction of ductwork. Turning vanes. 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. Leaks in duct work. Registers or grilles. 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 cabinet bulkhead.
TROUBLESHOOTING CHART SYMPTOM SOURCE PROBABLE CAUSE 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 fan outlet 8. Obstructions in high velocity air stream Fans which are normally used in duct systems are tested with a length of straight duct at the fan outlet. If there is no straight duct at the fan outlet, decreased performance will result. If it is not practical to install a straight section of duct at the fan outlet the fan speed may be increased to overcome this pressure loss. Observe fan RPM limits. 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 be high). Variable motor sheave not adjusted. Fan speed too fast. Static Pressure Incorrect 1. System fan or interpretation of measurements 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), air density and the amount of air flowing through the system. The static pressure measured in a "loose" or oversized system will be less than the static pressure in a "tight or undersized system for the same airflow rate. In most systems, pressure measurements are indicators of how the installation is operating. These measurements are the result of airflow and such are useful indicators in defining system characteristics. 2. System System has less resistance to flow than expected. This is a common occurrence. Fan speed may be reduced to obtain desire flow rate. This will reduce HP, conserve energy, and save operating costs.