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3. Handling / Rigging 

 

Air  handling  units  can  be  delivered  as 

separate section or completely assembled. 
To  prevent  damage  to  unit  cabinet,  a 
specific  lifting  method  for  offloading  the 

units is recommended as shown in Figure 
1.  
The  spreader  bars  must  be  in  position 

to  prevent  straps  or  cables  from  rubbing 
the  frame  panel.  Ensure  stability  and 
balance  when  lifting  the  units  and  avoid 

twisting  or  uneven  lifting.  Uneven  lifting 
may  lead  to  accident  or  fatality  which  is 

out  of  factory  responsibility.  Care  should 
be taken to prevent coil connections, drain 

pan  connection,  damper  operators  and 
accessory section from damage. 
Do not push hard on the unit it self of on 

the  metal  base.  Use  large  wooden  beam 
to  evenly  distribute  the  force.  Dropping 

the  units  will  result  in  permanently 
damage  of  ball  bearing,  fan  shaft  or 
loosen coil from the mounting. 

 

 

AHU with metal base 

 

AHU with wooden base 

 

Figure 1 - Lifting method when offloading units 

Transportation on the building site should 

be  done  using  forklift  truck  or  a  crane 
(See  Figure  2).  The  forks  must  only  be 

applied under the unit base frame and not 
against  the  panel.  In  case  when  fork  of 

the  forklift  is  too  short  then  suitable 
extensions should be used.  
 

 

Figure 2 - Transportation by forklift truck 

 

4. Storage 

 

For  external  storage  prior  to  installation, 

the  units  must  be  protected  from  dust, 
rain,  constant  sun  exposure  and  rodents. 

Although  covered  in  shrink-wrapped 
plastic  sheeting,  this  is  not  intended  for 
long-term  storage  and  should  be  remove 

as  soon  as  it  is  offloaded.  Unit  therefore 
should be more protected by tarpaulins or 

similar.  Avoid  exposed  the  units  for  coil 
connection damages by transient load. 
The  fan  impeller  or  motor  drive  must  be 

rotated  once  every  month.  Should  the 
units be stored for a period of exceeding 6 

months,  then  it  is  recommended  that  the 
drive  belts  be  removed  and  store 

separately.  

 

IMPORTANT 

INSTALLATION 

AND 

MAINTENANCE 

ARE 

TO 

BE 

PERFORMED  ONLY  BY  QUALIFIED 

AND  EXPERIENCED  PERSONNEL 

WHO 

ARE 

FAMILIAR 

WITH 

NATIONAL  AND  LOCAL  CODES 

AND REGULATION.  

 

5. Assembly and Installation  

 

5.1 General 

 

The system design and installation should 
follow accepted industrial practice, such as 

described in the ASHRAE Handbook. 
These  units  are  not  designed  to  be 
weatherproof  (unless  equipped  with 
canopy)  and  therefore  should  not  be 
installed  outdoors.  Flexible  connections 

should  be  used  on  the  outlet  and  inlet 
duct  connections  for  all  units.  A  minimal 

amount  of  air  leakage  is  normal  on  the 
cabinet  and  it  will  not  affect  unit 

performance.  The  air  handling  units  are 
not  design  to  be  suspended  from  the  top 
of  the  unit.  Therefore,  when  the  unit  is 

ceiling  hung, make sure unit is supported 
with a base rail of channel. 

Summary of Contents for DM AHU

Page 1: ...LATION OPERATION MAINTENANCE VER O AHU01 DEC20 15 The design and construction are subject to change without any notice for future improvement MODELS DM AHU DS AHU AHUR VRV AHU Double Skin Modular Air...

Page 2: ...rtificate which is determined by International National or Local Codes and Regulation Place of service should be equipped with the necessary protective equipment which provide safe maintenance 1 4 Uni...

Page 3: ...truck 4 Storage For external storage prior to installation the units must be protected from dust rain constant sun exposure and rodents Although covered in shrink wrapped plastic sheeting this is not...

Page 4: ...carefully assembled to desired unit arrangement The air handling units are design to use section joint brackets to combine two sections Section joints for cabinet and base frame are shown in Figure 5...

Page 5: ...on joint WARNING CABINET SECTION JOINTS ARE NOT INTENDED FOR LIFTING PURPOSE AND PULLING CABINET FROM A DISTANCE TO JOIN SECTION TOGETHER When the cabinets are penta post to penta post arrangement or...

Page 6: ...hipped out from factory See Figure 15 Figure 14 Restrained Spring Isolator Figure 15 Removing of U Shaped Plate 5 5 Arrangement VRV AHU Control box and expansion valve kit are installed on the air han...

Page 7: ...joints or flexible fittings are to be provided in all piping connections particularly those adjacent to heating source to absorb expansion and contraction strains Failure to comply will result in dama...

Page 8: ...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 valve is to be equipped with external equa...

Page 9: ...r control refer to the VFD manual for wire size and requirements Figure 22 3 phases motor connection diagram 5 7 2 Motor Cabling Motor wiring must go downward from motor terminal box to prevent conden...

Page 10: ...he diameter of smaller pulley Table 2 Adjusted Pitch Diameter Model VPT100Z1 VPT120A1 A2 VPT139A1 A2 VPT156A1 A2 VPT177A1 A2 VPT178B2 Max Pitch mm 96 114 4 133 4 150 4 171 4 171 Min Pitch mm 82 9 96 1...

Page 11: ...ee Table 2 Figure 27 When the required diameter is obtained adjustable flange is locked by tighten the four clamp screws To get the same diameter in the two grooves of pulleys screw the two mobile fla...

Page 12: ...out Notes 1 Elbows should not be closer than 2 1 2 times the Duct Equivalent Diameter Refer to Formula 1 2 Dampers should be placed at least fan diameters downstream of the fan discharge Formula 1 Duc...

Page 13: ...ther For DX coils it is advisable that the refrigerant is to be pumped into the condenser If this is not possible refrigerant shall be purged out WARNING DO NOT HEAT ANY PART ON DX COIL IF REFRIGERANT...

Page 14: ...20mm 6 1 5 Coils Check the pipe work to coil is correctly connected and the fins are free from foreign matter or damage Check that the condensate drain is trap Ensure good sealing of silicon around th...

Page 15: ...or cap screw are in secure position CAUTION HIGH AIR TEMPERATURE IN FAN SECTION CAN CAUSE MOTOR OVERHEAT AND DAMAGE ON DRAW THROUGH AIR HANDLERS ADJUST THE DISCHARGE AIR TEMPERATURE OF THE HEATING SE...

Page 16: ...ling heating efficiency Dry cleaning is done by using a powerful vacuum cleaner on the dust accumulated side If coil is very dirty coils need to be removed for wet cleaning by trained personnel Ensure...

Page 17: ...IR VELOCITY SHOULD NOT BE LOWER THAN 2 0 m s 7 7 Heat Wheel Heat Pipe The unit should be maintained in line with the manufacturer recommendation Please refer installation and maintenance manual for de...

Page 18: ...not evenly supported on foundation j Fan assembly s tolerance is out of range a Consult manufacturer b Remove transport bracket c Check pulley alignment d Re tension belts e Replace vibration isolato...

Page 19: ...he heat wheel baffle top 8 Assembled back the remaining panels 9 2 AHU Water Quality Water quality requirements Water softening treatment must be given in advance to prevent scaling in the heat exchan...

Page 20: ...Yes No 5 Correct incoming voltage that supplied to motor L1 L2 __________ L2 L3 __________ L3 L1 __________ 6 Rotate fan wheel whether it can rotate freely and without abnormal noise Answer Yes No 7 A...

Page 21: ...Are the AHU sections joined with section joint properly Answer Yes No 4 Are the joining between AHU sections sealed properly Answer Yes No Start Up Checking 1 Is fan rotated in correct direction Answe...

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