Dunham-Bush CS3 Series Instruction manual

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TABLE OF CONTENTS
SECTION PAGE
NOMENCLATURE................................................................................................................................ 3
INTRODUCTION
RECEIVING.......................................................................................................................................................... 4
STORAGE............................................................................................................................................................ 4
LONG-TERM STORAGE...................................................................................................................................... 4
HANDLING AND RIGGING.................................................................................................................................. 5
INSTALLATION
GENERAL............................................................................................................................................................. 6
FAN SYSTEM....................................................................................................................................................... 7
LEVELING FAN DECK ASSEMBLY..................................................................................................................... 7
CLEARANCE........................................................................................................................................................ 7
GENERAL PIPING PARAMETERS- HOT WATER COILS......................................................................... 8
STEAM COILS.................................................................................. 9
DIRECT EXPANSION COILS..........................................................10
SHEAVES AND BELTS.......................................................................................................................................11
BELT TENSION INSPECTION GUIDE................................................................................................................12
CONDENSATE DRAIN TRAPS...........................................................................................................................13
DUCT CONNECTIONS .......................................................................................................................................13
JUNCTION BOX CONDENSATE PREVENTION................................................................................................14
PHYSICAL DIMENSION......................................................................................................................................15
UNIT SHIPPING WEIGHTS (KG)........................................................................................................................17
DISCHARGE ARRANGEMENTS ........................................................................................................................18
WATER INLET AND OUTLET LOCATIONS .......................................................................................................19
FILTER ARRANGEMENTS.................................................................................................................................21
COMPONENTS ARRANGEMENT
BLOWER ARRANGEMENT ................................................................................................................................24
QUICK SERVICE ACCESS.................................................................................................................................24
FILTERS..............................................................................................................................................................24
COILS..................................................................................................................................................................24
FANS...................................................................................................................................................................25
MOTOR LOCATION............................................................................................................................................25
OPTIONAL...........................................................................................................................................................25
UNIT FEATURES AND ACCESSORIES
UNIT ASSEMBLY PLANNING.............................................................................................................................26
TYPICAL ARRANGEMENT.................................................................................................................................26
FAN BEARINGS..................................................................................................................................................27
VIBRATION ISOLATION .....................................................................................................................................27
OPERATION
PRE-OPERATION CHECK..................................................................................................................................28
PRESSURE DROPS ...........................................................................................................................................28
OPERATING LIMITATION...........................................................................................................................29
MAINTENANCE
PERIODIC INSPECTION.....................................................................................................................................30
ANNUAL INSPECTION .......................................................................................................................................31
TROUBLESHOOTING CHART.................................................................................................................32

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NOMENCLATURE
Each unit nameplate will carry the unit model designation.
The following gives a sample nomenclature of Dunham-Bush air-handlers
AHD FS 100 HL
MODULAR DESIGN
AHD= Air Handler Double
Skinned
FS= Forward Curved Wheel
AF= Air Foil Wheel
BF= Backward Curved
Unit Size = Nominal CFM
100
L= Low Pressure Unit Up
To 3.5” TSP
M= Medium Pressure Unit
Over 3.5” TSP
H= Horizontal
V= Vertical
M= Multi Zone

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INTRODUCTION
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.
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.
LONG-TERM STORAGE
If storing unit before installation, observe the following precautions,
1. The storage site should be level, rigid, and free of debris. If the site is in a heavy rain area, set
the unit off of the ground.
2. Do not store the unit in a heavy traffic area or on a vibrating surface. Vibration can damage
stationary bearings.
3. Monthly move the coverall, enter the fan section through the access door, and slowly rotate the
fan and motor by hand. This operation prevents bearing corrosion by redistributing the bearing
grease.
4. 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.

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Suitable extension should be used in case when
fork of the forklift is too short
The maximum permissible load is restricted by
the lifting capacity of the slings
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.
Figure 1: Typical Rigging

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INSTALLATION
GENERAL
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.

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INSTALLATION
Fan System
The fan section needs to be checked
carefully before the unit is turned on.
After removing all transportation
protections (only in case when spring
shock absorbers are installed) one
should check if there are any objects
near the fan, which could be sucked
into the impeller after it is turned on.
See Figure 2.
Figure 2
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 3). 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.
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 3: Spring Floor Mount
Curb mounted and weather-proof units can be provided upon request.

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PLUG COCK
GAGE COCK
THERMOMETER
DIRTLEG WITH GATE
VALVE (7/8"OD MIN.)
GATE
VALVE
PROPORTIONAL REMOTE
BULB TEMP. CONTROL
3 WAY MIXING
VALVE
AIR VENT
AIR FLOW
SUPPLY
RETURN
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 4: Hot Water Coil Piping Layout

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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 5: Steam Coil Piping Layout

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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 6.
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
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.
Figure 6: DX Coil Piping Arrangement
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.