AirComm Corporation Bell 429 Air Conditioning 429EC200M1Rev9 User Manual

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 3 
In  addition  to  the  revision  of  the  manual,  those  changes  categorized  as safety-of-flight 
shall  have  a  Service  Bulletin  issued to  the  operator  providing  the  necessary  information 
to comply with or to correct the safety-of-flight issue. 
 
Replacement or revised copies of this manual can be obtained by contacting: 
 
Air Comm Corporation Service Department 
1575 W. 124th Ave STE 210 
Westminster, CO.80234 
Phone No. 303-440-4075 Fax No. 303-440-6355 
Email: [email protected] 
12. Changes to Instructions for Continued Airworthiness 
Changes made to a line or paragraph of this document will be indicated by a vertical bar 
in the right hand margin. A complete page change will be indicated by a vertical bar next 
to the page number. 
 
(Example: Any change will appear with a vertical bar next to that change). 
13. Air Conditioner Features 
 
The  vapor  cycle  air  conditioner  features  one  or  two  forward mounted  evaporator(s) 
(cockpit), one  or  two  aft  mounted  evaporator(s) (main  cabin),  one  condenser  and one 
compressor belt-driven  by  the  transmission  output  quill.  These  components  combine  to 
provide  “conditioned  air”  through  the  existing  air  distribution  system  when  the  engines 
are operating during both ground and flight operations. 
 
This system can be operated in either the Air Condition (A/C), or Blower Mode. 
 
In  the  A/C  Mode,  conditioned  air  is  provided  by  the  forward  and  aft  evaporators  to  the 
cockpit and main cabin areas respectively. 
 
In  Blower  Mode,  the  evaporator  blowers  are  used  to  circulate  cabin  air,  while  the 
compressor clutch remains disengaged. 
 
The A/C system is connected electrically to the aircraft’s DC Power Panel 28 VDC Bus. 
 
The  control panel  for  the  A/C  system  is  located  in  the  aft  section  of  the  existing  center 
console  between  the  pilot’s  and  copilot’s  seats.  This panel consists  of  the  A/C  &  Fan 
Switch,  two  potentiometers  (for  the  control  of  cockpit  and  cabin  evaporator  blower 
speed) and a temperature control rheostat. 
 
 
 
Figure 1:  Cockpit A/C Control Panel  
						

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The  blower  motors feature  variable  fan  speed. This  feature  can  be  used  in  both  the  fan 
and air conditioner modes. 
 
The compressor is mounted to the surface of the main rotor gear box and is driven by a 
Poly  V-Belt  and  a  pulley  which  is  mounted  to  the  transmission  drive  quill.  Access  to  the 
compressor is provided by the transmission compartment access doors. 
 
Airflow  through  the  condenser  heat  exchanger  is  provided  by  one  28  volt  DC  high 
performance  blower,  and  is  enhanced  by  means  of  a  large  cut  out  in  the  transmission 
cowling providing ram air in forward flight. 
 
The right side aft evaporator is equipped with a Freeze Switch. The Freeze Switch probe 
is located in the core of the evaporator heat exchanger. This unit performs two functions; 
1.  It  acts  to  prevent  coil  freeze-up  by  limiting  the minimum  coil  temperature  to  32º  F  (0º 
C),  and  2.  It  acts  in  conjunction  with  the  cabin  air  temperature  control  system,  by 
controlling  the  bypass  of  refrigerant  through  the  evaporator  coil  in  response  to 
adjustment  of  the  thermostat switch  located  on  the  left  hand  lower  section  of  the 
instrument panel. 
 
Each  evaporator  has  an  overboard  drain  to  remove  condensate  from  the system.  The 
forward  evaporator(s)  are  drained  overboard  directly  underneath  each, through  the 
bottom  nose  skin. See Figure 12 and Figure 13. The  aft  evaporator  drain(s)  run  from 
each  evaporator  through  bulkhead  fittings  in  the  transmission  deck  into  flexible  tubing 
through the overhead and left door post. They continue under the floor along the left keel 
beam  then  aft  through  check  valves  and  out the  left  bottom  skin.  See Figure 25 and 
Figure 26. 
 
The  refrigerant  plumbing  for  this  system  installation  incorporates  insert O-Ring and 
TORQ LOK® fittings: 
 
A. INSERT  O-RING  FITTINGS: These fittings  have  formed  ends  that  along  with  an 
O-Ring create  a  seal.  Caution  when  assembling  these  fittings; care  should  be 
taken  not  to  damage  the O-Ring (i.e.  nicking,  splitting,  or  crushing,  etc.).  These 
fittings  are  signified  by  a  green  band  placed  around  the  outside  diameter  of  the 
hose  or  tube  they  are  utilized  on. Black O-Rings  must  not  be  used  on  these 
fittings. (See Chapter 7 for torqueing procedures). 
 
B. TORQ  LOK®  FITTINGS:  These  fittings  have  two  flat  mating  surfaces  that  along 
with  an  O-Ring  create  a  seal.  Caution  when  assembling  these  fittings; care 
should  be  taken  not  to  damage  the O-Ring (i.e.  nicking,  splitting,  or  crushing 
etc.). Green O-Rings  must  not  be  used  on  these  fittings. (See Chapter  7 for 
torqueing procedures). 
 
The system is also equipped with a Binary switch. This switch is designed to protect the 
system  against  over-pressure  situations,  or  under-pressure  in  the  event  of  refrigerant 
loss from the system. The switch also prevents the system from operating in low ambient 
temperatures below 50º F (10º C). 
 
   
						

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The switch operating pressures are: 
 
Low Pressure Function: 
Cut-out at 28 ± 2.8psi (2.0 ± .2 Kg/cm²) 
Cut-in at 29 ± 4.3 psi (2.1 ± .3 Kg/cm²) 
 
High Pressure Function: 
Cut-out at 384 ± 30psig (28.0 ± 2.0 Kg/cm²) 
Cut-in at 298 ± 43psig (20.9 ± 2.0 Kg/cm²) 
 
14. Description of Vapor Cycle Air Conditioner and Installation 
 
This  section  contains  a  general  overview  of  a vapor-cycle  air  conditioning  system  and 
how  it  functions.  This  type  of  system  operates  in  a  closed  loop,  in  which  the  refrigerant 
absorbs heat from the cabin and ejects it into the outside air. The refrigerant then returns 
to  the  cabin  to  repeat  the  cycle.  The  operation  of  the  system  is  described  below (See 
Figure 2). 
 
Liquid refrigerant is contained in the receiver-drier under pressure from the compressor. 
The  receiver-drier  also  filters  the  refrigerant  through  a  material  know  as  desiccant.  The 
desiccant insures that the liquid refrigerant leaving this component is free of any water or 
other contaminants. 
 
The low pressure (suction) line from the compressor is attached to the evaporator lines, 
and  causes  the  refrigerant  to  be  pulled  out  of  the  receiver-drier  and  through  the 
expansion valves. The expansion valves serve as a controlled spray orifice, to spray the 
correct amount of refrigerant into the evaporator. This regulation of refrigerant allows the 
liquid to absorb the heat from the cabin air, and transform it to a vapor state just prior to 
its exiting the evaporator assembly. 
 
The  low  pressure  vapor  is  then  drawn  into  the  compressor  where  its  pressure  is  raised 
to approximately 200 psig (14.06 kg/cm) and its temperature to around 200º F (93.3º C). 
This  high  pressure/high  temperature  vapor  then  travels  to  the  condenser  (a  heat 
exchanger cooled by a flow of outside air). Heat is extracted from the refrigerant, and as 
it cools it condenses back into a liquid and flows into the receiver-dryer, ready to repeat 
the cycle. 
   
						

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15. Refrigeration Cycle Illustration 
 
 
 
 
Figure 2:  Refrigeration Cycle Illustration 
(NOTE: This illustration is provided as a reference only and may not match actual installation) 
 
 
High pressure liquid 
Low pressure vapor 
Low pressure liquid 
High pressure vapor 
Compressor 
Condenser 
Aft Evaporator 
Receiver- 
Drier 
Bypass 
Valve 
Expansion 
Valves 
Fwd Evaporator  
						

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CHAPTER 2 
AIRWORTHINESS LIMITATION SECTION 
 
1. Airworthiness Limitations 
 
The  Airworthiness limitations  section  is  FAA  approved  and  specifies  inspections  and 
other  maintenance  required under  Sections  43.16  and  91.403  of  Federal  Aviation 
Regulations unless an alternative program has been FAA approved. 
 
No airworthiness limitations associated with this type design change. 
 
 
 
 
 
ACO Approval                                                                             Date  
						

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CHAPTER 3 
INSPECTIONS AND OVERHAUL  
 
1. Inspection Requirements 
 
PERIODIC INSPECTIONS 
(Hours are aircraft time) 
 
NOTE 
The  429EC-250  provisions  kit  does  not  require periodic  inspection  until 
the  429EC-200, 429EC-202,  429EC-204,  or  429EC-206 Air  Conditioner 
kit has been installed.  
 
Item Annual 
Every 200 +/- 20 
Hours of 
Operation 
Special inspection instructions. 
(Paragraph) 
Fwd Evaporator 
Blower X  
 
Check for operation throughout entire 
range of speed for blower operation. 
(A) 
Aft Evaporator 
Blower X  
Check for operation throughout entire 
range of speed for blower operation. 
(A) 
Condenser Blower 
Motor and Fan 
Assembly 
X  Check for operation. (B) 
Compressor Drive Belt X X 
Check for signs of excessive wear 
(Example: Glazing, Cracks and 
Exposed Fibers). (C) 
Air Conditioner 
Placards and Markings X  Check for security and legibility. (D) 
Compressor Assembly X X 
Check for operation, security of 
attaching hardware and signs of 
refrigerant or oil leaks. (E) 
Compressor Mount X X Check for cracks and security of 
attaching hardware. (F) 
Plumbing and Fittings X X Check for security and signs of oil or 
refrigerant leaks. (G) 
Air Conditioner 
Compressor Drive 
Pulley 
X X Check for security of attaching 
hardware. (H) 
Blower Electrical 
Connectors X  
Visually inspect the condenser and 
evaporator blower connectors for 
signs of overheating 
 
   
						

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2. Inspection Procedures 
 
NOTE 
Refer  to  Chapter 4,  Location  and  Access,  to  locate  all  aforementioned 
components for inspection. 
 
A. Inspection of the Fwd and Aft Evaporator Blower Motors: 
 
CAUTION 
Fans  are  designed  to  operate  with  the resistance  of  the  entire  ducting 
system.  Operation  of  the  evaporator  fans  with  any  part  of  the  distribution 
system removed may cause permanent damage to the fan motor. 
 
WARNING 
Fans  may  take  up  to  10  seconds  to  start  after  the  switch  is  turned  on. 
Keep hands away from fan wheels or blades whenever switch is in Fan 
or A/C positions. 
 
At the Cockpits A/C Control Panel place the AIR COND switch in the FAN position and 
verify: 
 
1) That  both  the  fwd  and  aft  fans  are  activated  and  operating. Rotate  speed 
control knobs to verify blowers increase and decrease speed accordingly. 
2) That the condenser fan is non-operational. 
3) That  the  compressor  clutch  is  disengaged  and  the  “AIR  COND FAIL” 
message is not illuminated on the ADIU display. 
 
Place the AIR COND switch in the OFF position and verify: 
 
1) That both the fwd and aft fans deactivate. 
2) That  the  compressor  clutch  remains  disengaged  and  the “AIR  COND  FAIL” 
message is not illuminated on the ADIU display. 
 
B. Inspection of the Condenser: 
NOTE 
This inspection may be performed with the air conditioner charged with refrigerant or 
it may be performed with no refrigerant in the system. In the case where there is no 
refrigerant in the system or the system is low on refrigerant or in the case where the 
ambient temperature is low, the binary switch will need to be jumpered. The 
temporary installation of a jumper wire across the terminals of the binary switch will 
do no harm even if it was not necessary. 
 
CAUTION 
This procedure requires the temporary installation of a jumper wire across 
the  terminals  of  the  binary  switch.  This  wire MUST be  removed  after  this 
inspection is accomplished.  
 
1) Visually  inspect  condenser  air  inlet  for  any obstructions  or  debris.  Airflow  in  
						

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this area is critical for air conditioner operation. 
2) Disconnect  electrical  leads  from  the  binary  switch  and  install  a  jumper 
between the leads. 
3) Connect  28V  ground  power  to  the  aircraft  and  place  the  A/C  mode  switch  in 
the “A/C” position and verify: 
a. Condenser fan is activated and operating. This fan should pull air into 
the aircraft through the condenser assembly. 
b. Compressor  clutch  is  engaged  and  the  “AC  COMP  FAIL”  message  is 
not illuminated on the ADIU display. 
c. Disconnect  one  of  the  electrical  leads  from  the  binary  switch,  remove 
jumper  wire  and verify  that the  “AC  COMP  FAIL”  message  is 
illuminated on the ADIU display. 
4) Reconnect the electrical leads removed from the binary switch. 
5) Place the A/C mode switch into the Off position and verify: 
a. The condenser fan deactivates. 
b. The compressor clutch disengages and all blowers deactivate. 
 
C. Inspection of the Drive Belt: 
 
1) Remove  transmission  cowling  to  gain  access  to  compressor  drive  belt  and 
visually inspect the A/C compressor drive belt for the following: 
a. Any signs of excessive wear. 
b. Any signs of glazing. 
c. Any cracks or missing pieces. 
d. Any exposed fibers. 
2) Verify  proper  belt  tension  as  shown  in  the  illustration  shown  below.  (See 
Figure 3) 
 
 
Figure 3:  Belt Tension Inspection 
 
D. Inspection of Placards And Markings: 
 
1) Check all air conditioner placards and markings for security and legibility. 
 
E. Inspection of Compressor Assembly: 
 
NOTE: 
The  air  conditioning  system  must  be  serviced  with  refrigerant  to  perform  
						

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this inspection. 
 
1) Connect  28V  ground  power  to  the  aircraft  and  place  the  A/C  mode  switch  in 
the  “A/C”  position  and  verify that  the Compressor  clutch  is  engaged  and  the 
“AC COMP FAIL” message is not illuminated on the ADIU display. 
2) Place  air  conditioner  switch  to  the  OFF  position  and  verify  that  the 
Compressor  clutch  is  disengaged  and  the  “AC  COMP  FAIL”  message  is  not 
illuminated on the ADIU display. 
3) Visually inspect the compressor assembly for the following. 
a. Security of all attaching hardware. 
b. Signs of refrigerant or oil leaks. 
c. Signs of excessive belt slippage or excessive heat. 
 
F. Inspection of Compressor Mount Assembly: 
 
1) Visually inspect compressor mount of any signs of the following: 
a. Any cracks. 
b. Security of attaching hardware. 
c. Elongation of component mounting holes. 
 
G. Inspection of A/C Refrigerant Plumbing: 
 
1) Visually inspect for any signs of the following:  
a. Refrigerant gas leaks. 
b. Refrigerant oil leaks. 
c. Chaffing or excessive corrosion. 
d. Security of attaching hardware. 
 
H. Inspection of Compressor Drive Quill (Part of the 429 aircraft type design): 
 
1) Inspect security of attaching hardware. 
 
 
I. Inspection of Blower Electrical Connectors 
 
1) Locate  the  electrical  connectors  that  power  the  evaporator  and 
 condenser  blowers.  The  connectors  are  at  the  interface  between  the 
 blower  harness  and  the  aircraft  harness  and  identified  by  their  white 
 plastic housing. 
2) De-mate  each  connector  and  inspect  both  mates  for  signs  of 
 overheating (discoloration or plastic deformation).  
3) If  any  signs  of  overheating  of  the  housing  are  present the  system 
 must be rendered inoperative and the connector housing and contacts 
 replaced before further operation. 
 
  
						

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3. Component Overhaul / Replacement Schedule 
 
 
Part Number  Description  Recommended replacement  
S-6029EC-11 (LH) 
S-6029EC-12 (RH) 
 
Forward Evaporator 
Blower Motor Assy 
Every five years or 1500 hours. Acceptable to 
operate motor until failure as it poses no safety 
of flight risks. 
429EC-6302-11 (LH) 
429EC-6302-12 (RH) 
 
Aft Evaporator 
Blower Motor Assy 
Every five years or 1500 hours. Acceptable to 
operate motor until failure as it poses no safety 
of flight risks. 
S-6063EC-1 
S6085EC-2 
(optional) 
 
Condenser Blower 
Assy 
Every five years or 1500 hours. Acceptable to 
operate motor until failure as it poses no safety 
of flight risks. 
ES35429-1 Compressor Drive 
Belt 
Every 1000 hours or as condition dictates. 
S-3038EC-1 
 
Compressor 
 
Every 1000 hours. Acceptable to operate 
compressor until failure as it poses no safety of 
flight issues.