AirComm Corporation Bell 429 Air Conditioning 429EC200M1Rev9 User Manual

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 33 
 
 
 
Figure 25:  Aft Evaporator Drain Line Routing, Dual Evaporators 
 
 
 
 
 
Figure 26:  Aft Evaporator Drain Line Routing, Single Evaporators 
 
   
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 8 Page 34 
 
CHAPTER 5 
PLACARDS AND MARKINGS 
1. Placard and Marking Information 
 
 
All  placards  and  markings  associated  with  the  installation  of the  air conditioner  system  are  part 
of  the  type  design  of  this  helicopter.  Please  refer  to  the  Bell Helicopter  Instructions  for 
Continued Airworthiness Manual for placards and markings information. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
THIS AREA INTENTIONALLY LEFT BLANK 
 
  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 35 
CHAPTER 6 
SERVICING 
1. Safety Precautions 
 
CAUTION 
Refrigeration  servicing  should  be  performed  by  qualified  personnel  only. 
Check  all  local  and  federal  regulations  before  servicing  any  refrigerant 
system or storage device. 
 
The  refrigerant  used  in  the  air  conditioning  system  is  the  environmentally  safe  HFC 
R134a.  This  refrigerant  is  non-explosive,  non-flammable,  and  non-corrosive,  has 
practically  no  odor,  and  is  heavier  than  air. However,  certain  precautions  must  me 
observed to ensure the safety of the equipment and any personnel servicing this system. 
 
HFC R134A  is  stored  in  a  liquid  state.  It  will  rapidly  evaporate  or  sublimate  when 
exposed  to  normal  temperature  and  atmospheric  pressure.  This  rapid  evaporation  can 
causes  a  severe  drop  in  temperature. If  liquid  refrigerant  comes  in  contact  with  the  skin 
or eyes it may cause severe frostbite or blindness. Care must be taken to prevent liquid 
refrigerant from contacting the skin or the eyes. 
 
WARNING 
Safety  glasses  must  be  worn  at  all  times  when  servicing  the  air 
conditioning  system. Should  any  liquid  refrigerant  come  in  contact  with 
the  skin  or  eyes  seek  medical  attention  immediately  even  if  the  irritation 
ceases. 
 
WARNING 
To  avoid  a  potential  explosion  NEVER  weld,  solder, steam  clean,  use  a  flame 
type  leak  detector,  blow  torch,  bake  on  aircraft  finish, or  use excessive heat on, 
or in the immediate area of refrigerant lines or supply tanks while they are closed 
to the atmosphere. 
 
WARNING 
Refrigerant  servicing  must  be  performed  in  a  well-ventilated  area  to 
minimize inhalation of the refrigeration gas. 
 
2. Servicing Information 
 
CAUTION 
Refrigeration servicing should be performed by qualified personnel only. 
 
NOTE 
A list of suggested servicing equipment is provided later in this chapter. 
 
2.1 Servicing Procedure using a Service Cart 
 
A. Connect the servicing manifold to the servicing ports located on the forward R/H side of 
the  transmission  deck.  BLUE  for  low  pressure  or  “Suction”  and  RED  for  high  pressure 
or “Discharge.”  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 36 
 
B. After  the  quick  disconnect  fittings  have  been  attached  to  the  servicing  ports,  tighten  the 
knobs on  the  back  of  the  fittings  to  engage  the Schrader  valves  located  inside  the 
charging ports. 
 
NOTE 
The Schrader valves inside the charging ports MUST be engaged to allow 
servicing of the air conditioner system. 
 
C. Connect  the  YELLOW  line  in  the  center  of  the  manifold  to  the  vacuum  pump.  Turn  the 
vacuum  pump  on and  open  both  valves  on  the  charging  manifold.  Decreasing  the 
pressure  in  the  closed  system  to -29.40  InHg  causes  the  moisture  in  the  system  to 
vaporize  allowing  it  to  be  drawn  out  by  the  vacuum  pump.  Removal  of  all  moisture  is 
crucial to the operation of the A/C system. Any moisture left in the system will be turned 
into ice causing undesired operation or blockage of one or more expansion valve. Allow 
the vacuum pump to draw against the system for a minimum of ONE HOUR. 
 
NOTE 
Due  to  a  drop  in  atmospheric  pressure  with  an  increase  in  altitude,  the 
normal  vacuum  reading  will  drop  1”  (1  kg/cm)  for  each  1000  ft  of  altitude 
gained  e.g., Sea  Lever  Reading  =  10  InHg,  reading  at  1000  feet  above 
sea level = 9 InHg. 
 
D. After the system has been evacuated, turn both valves on the manifold assembly to the 
“OFF”  position  and  switch  the  vacuum  pump  off.  Allow  the  system  to  hold  the  vacuum 
for  a  minimum  of ONE  hour  to  check  for  vacuum  leaks. If  the  system  will  not  hold  the 
vacuum, the system may have a fitting leak. It may be necessary to charge the system 
with one to two pounds of refrigerant and conduct a leak check using an electronic leak 
detector. 
 
CAUTION 
To ensure trouble free operation the system must be leak free. 
 
E. After the leak check has been performed evacuate the system for a minimum of ½ hour 
before charging per the levels below: 
 
 429 air conditioning system with dual Fwd evaporators, 2.7 lbs (1.2247 Kg) of 
 refrigerant. 
 429 air conditioning system with single Fwd evaporator, 2.5 lbs (1.1340 Kg) of 
 refrigerant. 
 
NOTE 
  Static charging is the most accurate and safest way to charge an air conditioning  
  system. To accomplish this all 2.7 Lbs. of refrigerant must be charged into the  
  system without the compressor engaged or the system operating. If the 
  system must be serviced with the compressor running, servicing must be   
  performed through LO (BLUE) side only! Please make sure that the HIGH (RED)  
  side valve stays closed during this procedure and any time the system is   
  operating. Never Charge through the Discharge or “HIGH” (RED) side of the  
  system while the compressor is running as this may cause severe damage to the 
  compressor Assy.  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 37 
 
 
CAUTION 
Operating  the  air  conditioning  system  with  a  low  refrigerant  charge  may 
cause severe damage to the compressor assembly. 
 
F. After  charging,  perform  a  test  run  to  ensure  proper  function  of  the  Air  Conditioning 
System. 
 
 
      2.2 Servicing Procedure without using a Service Cart 
A. The following tools & materials will be required: 
 1. R134a Manifold Gauge Set 
 2. 3 pound bottle of R134a 
 3. Refrigerant Scale to weigh the refrigerant bottle 
 4. Vacuum Pump capable of maintaining 29in Hg of mercury at sea level 
 5. Ultra PAG oil 
 
B. Charging procedure: 
 Note that the following steps 1 through 7 are to be accomplished while the aircraft 
 and air conditioning system are “OFF”. 
  
 1. Connect the servicing lines from the manifold gauges to the servicing ports located on 
     the forward R/H side of the transmission deck. The BLUE port is for low pressure  
     (suction) and the RED port is for high pressure (discharge). 
  
 2. After the quick disconnect fittings have been connected to the servicing ports, tighten 
     the knobs on the back of the fittings to engage the Schrader valves located inside the        
     charging ports. If the knobs are not properly tightened, the Schrader valve inside of     
     the ports will not engage. 
 
 3. To ensure there is no air or moisture in the system, use the Manifold Gauges and 
     Vacuum Pump to pull the system down on a vacuum continuously for a minimum of 1     
      hour. To perform this, connect the YELLOW line in the center of the manifold to the   
     vacuum pump. Turn the Vacuum pump on and open both valves on the charging   
     manifold until the pressure has decreased to 29.40 in Hg. 
 
 4. After 1 hour of vacuuming and while the vacuum pump is still working, close both   
     valves on the manifold gauge set and watch the High and Low pressure gauges to   
     ensure the system pressures remain constant or “vacuumed.” If the system does not   
     hold a vacuum it has a leak. 
 
 5. Once the system has been proven to be “Leak Free,” disconnect the vacuum pump   
     and connect the refrigerant bottle to the manifold gauge set. 
 
 6. Purge the line between the refrigerant bottle and manifold gauge by opening the knob 
     on the refrigerant bottle. Then, loosen the line at the manifold slightly to allow the   
     refrigerant to push the air out. This will verify that there is no air in the line. 
 
 7. Charge the system by opening the low side and high side valves which will allow    
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 38 
     the initial charge of 2.0 pounds to be added. This can be measured and tracked by  
     placing the bottle on a scale. 
 
  
 Note that the following step 8 is to be accomplished while the aircraft is running at 
 100%  and the air conditioning system is “ON”. Ensure that the High side (RED) 
 is closed at all times while system is operating.) 
 
 8. Add the remainder of the required charge in 0.2 lb. increments by opening the low   
    side (BLUE) slightly to allow the refrigerant to be drawn in. Allow two minutes       
    to elapse between each addition of refrigerant. The amount entering the        
    system can be verified by monitoring the scale as the refrigerant is added. Note that  
    the compressor can be damaged if an excessive amount is added. Charge the system     
    as listed  below: 
 
    429 air conditioning system with dual Fwd evaporators, 2.7 lbs (1.2247 Kg) of   
    refrigerant. 
    429 air conditioning system with single Fwd evaporator, 2.5 lbs (1.1340 Kg) of   
    refrigerant. 
 
WARNING 
If charging is to be accomplished with the compressor engaged it must be 
accomplished  through  the  LO  (BLUE)  side  only. Never  Charge  through 
the  Discharge  or  “HIGH”  (RED)  side  of  the  system  while  the 
compressor  is  running. This  may  cause  severe  damage  to  the 
servicing  equipment  and  may  cause  personal  injury  or  death.  Care 
should be taken to ensure the HIGH (RED) side valve stays closed during 
this procedure and any time the system is operating. 
 
CAUTION 
When  reclaiming  refrigerant,  be  sure  to  note  any  oil  that  is  removed  from  the  system,  and 
replace the  lost  oil  before  or  during  re-servicing.  Maintaining  a  proper  oil  and  refrigerant 
charge  is  critical  to  the  life  of  the  compressor  assembly. Excessive  system  oil  charge  will 
reduce cooling performance. 
 
 
2.3 Ambient Temperature effects on servicing 
Running  the  system  when  the  ambient  temperature  is  below  80 OF  will  present  unusual 
(low) suction and discharge pressures on system gauges. An overcharge condition is likely 
if the process described in section 2.1 is followed when the ambient temperature is below 
80 OF. Running the air conditioning system when the outside air temperature is appreciably 
colder  than  the  normal  design  operating  temperatures  may  result  in  damage  to  the 
compressor. The following guidelines will provide means to mitigate the chances of system 
damage. 
The following  assumes that  the  system  is  either a  freshly  installed  system  or  a  previously 
operated system with a newly installed compressor.  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 39 
 Ambient temperature above 80OF: 
If  the  system  was  charged  by  refrigerant  weight  utilizing  a charging  station  and  the 
compressor  has  not  been  rotated  since  the  oil  and  refrigerant  were  added,  then 
manually rotate the compressor shaft clockwise a minimum of 10 full revolutions prior to 
running  the  compressor.  A  socket  or  wrench  applied  to  the  shaft nut  is  the 
recommended  method.  Always  rotate  clockwise  to  insure  against  loosening  the 
compressor shaft nut. 
If  the  system  was  charged  per section 2.2 of  this  Chapter  then  disregard  manual 
rotation. 
Operate  system  normally,  check  for  evaporator  fan  operation  on  both  high  and  low 
speed settings. Insure that condenser fans are operating and airflow direction is correct.  
 Ambient temperature between 60 OF and 80 OF: 
At  these  ambient  temperatures  system  charging  is  to  be  accomplished  by  refrigerant 
weight.  The  method discussed in section  2.2 is  not  applicable  at  these  condenser  inlet 
temperatures.  It  is  recommended  that  the  aircraft  heater  be  used  during  air  conditioner 
system testing in order to provide a heat load to the evaporators. 
Manually rotate the compressor shaft clockwise a minimum of 10 full revolutions prior to 
running  of  compressor.  A  socket  or  wrench  applied  to  the  shaft  nut  is  recommended 
method. Always rotate clockwise to insure against loosening the compressor shaft nut. 
Normal  suction  and  discharge  pressures  are  not  expected  under  these  conditions  and 
the  evaporators  may  be  cold  enough  to  cause  the  freeze  switch  to  activate  and  the 
bypass valve to open and close in a cyclic pattern. 
Even  though  the  bypass  valve  may  be  cycling  this  test  may  be  conducted  for  sufficient 
time  to  thoroughly  check  for  condenser  blower  and  fan  operation.  Check  for  evaporator 
fan  operation  on  both  high  and  low  speed  settings.  Insure  that  the  condenser  fan  is 
operating  and the  airflow  direction  is  correct.  Low  side  pressure may  be  observed  to  be 
higher than expected when the bypass valve is open. 
 Ambient Temperatures between 60 OF and 32 OF: 
At  these  ambient  temperatures  system  charging  is  to  be  accomplished  by  refrigerant 
weight.  The  method discussed in section  2.2 is  not  allowed  at  these  condenser  inlet 
temperatures.  It  is  required  that  the  aircraft  heater,  or  another  means  of  elevating  the 
evaporator  inlet  air,  be  used  during  air  conditioner  system  testing  in  order  to  provide  a 
heat load to the evaporators. 
It  is  recommended  that  the  aircraft  be  warmed  in  a  heated  hangar  immediately  prior  to 
running the air conditioner test. Upon removing the aircraft from the heated environment 
the test should be started within ten minutes or as soon as practical.  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 40 
Manually rotate the compressor shaft clockwise a minimum of 10 full revolutions prior to 
running  of  compressor.  A  socket  or  wrench  applied  to  the  shaft  nut  is  recommended 
method. Always rotate clockwise to insure against loosening the compressor shaft nut. 
Normal  suction  and  discharge  pressures  are  not  expected  under  these  conditions  and 
the  evaporators  may  be  cold  enough  to  cause  the  freeze  switch  to  activate  and  the 
bypass valve to open and close in a cyclic pattern. 
At  these  ambient  temperatures  this  test  should  not  be  conducted  for  more  than  15 
minutes.  Testing  the  evaporator  fan  operation  using  the  vent  position  prior  to  rolling  out 
of the hangar and prior to running the air conditioner system is recommended. Check for 
evaporator fan operation on both high and low speed settings. Insure that condenser fan 
is operating and the airflow direction is correct. 
 Ambient Temperature less than 32 OF: 
There  is  no  safe  way  to  operate  the  air  conditioning  compressor  with  ambient 
temperatures  below  32 OF.  Much  of  the  system  can  be tested for  proper operation  even 
though the compressor cannot be run. 
Charge the system by refrigerant weight only. 
Manually  rotate  the  compressor  shaft  clockwise  a  minimum  of  10  full  revolutions.  A 
socket  or  wrench  applied  to  the  shaft  nut  is  recommended method.  Always  rotate 
clockwise to insure against loosening the compressor shaft nut. 
Temporarily disconnect the wire energizing the compressor clutch. 
Run  the  aircraft  and  turn  the  switch  to  air  conditioning.  Check  the  condenser  fan  for 
operation and correct direction of airflow. Check evaporator fans for airflow on both high 
and low settings. 
 
2.4 Purging procedure  
 If the system has become contaminated or if the amount of oil in the system is unknown, 
 the following purge steps will prep the system for charging.  
 
 1. Remove all refrigerant from the system and discard. Ensure the charging station is     
     cleaned afterwards from the contaminated oil and refrigerant. 
 
 2. Disconnect all tubing and hoses from the system components. 
 
 3. Purge all hoses and tubes using solvents specifically made for air conditioning      
     systems such as Four Seasons Dura II A/C flush solvent (Isopropyl alcohol or     
     Denatured alcohol are acceptable substitutes). A/C flushing equipment available from      
     sources such as hecatinc.com is also recommended. 
 
 4. (This step does not need to be completed if the compressor is being replaced)  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 41 
     Remove the compressor from the aircraft, remove the drain plug and let the        
     compressor drain. Rotate the compressor and allow it to drain again. Repeat this      
     process until the compressor no longer has fluid inside. Do not use solvent to clean   
     the compressor. This will damage and possibly destroy the compressor. Add 8.0   
     ounces of Ultra PAG oil to the compressor (see section 3.0 below) and ensure the O-  
     ring on the drain plug is undamaged and retighten. 
 
 5. Purge the evaporators using air conditioner solvent (or equivalent i.e. Isopropyl  
     alcohol, Denatured alcohol). Flush the evaporator in the same direction as refrigerant   
     flow. The solvent should enter from the expansion valve side and exit on the     
     discharge side until the solvent runs out clean. 
 
 6. Purge the condenser using air conditioner solvent (or equivalent i.e. Isopropyl alcohol, 
     Denatured alcohol). 
 
 7. Flush the bypass valve with air conditioner solvent. Do not use pressure to force   
     solvent through the valve. 
 
 8. Replace the receiver drier bottle. THIS IS CRITICAL AND MUST BE PERFORMED. 
 
 9. Reconnect all components. Replace O-rings as needed. 
 
 10.Reconnect the compressor hose and place the system on a constant vacuum for 1   
      hour minimum. 
 
 11. Service the system with fresh R134a refrigerant and run an operational check out. 
 
3. Lubrication Information 
 
SYSTEM DESCRIPTION REFRIGERANT CHARGE OIL CHARGE 
429 air conditioning system 
with dual fwd evaporators 
 
2.7 lbs 
 
1.2247 Kg 8.0 oz. 237 ml 
429 air conditioning system 
with single fwd evaporator 
 
2.5 lbs  
 
1.1340 Kg  8.0 oz 
 
237 ml 
 
 
CAUTION 
This system may be serviced with either Polyolester (POE) or Double End Capped Polyalkylene 
Glycol (DEC PAG, also known as Ultra PAG) oil.  Polyalkylene Glycol oil is preferred due to its 
superior lubricating properties and improved compressor service life.  There are several types of 
PAG available. Only the “Double End Capped” type is permissible in Air Comm Corporation air 
conditioning systems.  Double End Capped PAG oil is available from Air Comm Corporation in 8 
ounce bottles (P/N ES94006-13).  Mixing of POE and PAG is acceptable.  Disregard previous 
statements to the contrary. They referenced PAG oil that was not “Double End Capped”.  Current 
versions of compressors are designed to be operated using PAG oil.  Testing by Air Comm 
Corporation has shown that “Double End Capped” PAG is compatible with POE and can therefore 
be mixed. “Double End Capped” is a reference to the chemical structure of the molecule and not to 
the container.  
						

							AIR CONDITIONER SERVICE MANUAL 429EC-200M-1 
Revision 9 Page 42 
 
Do not use Mineral oil in this system with R134a refrigerant. Do not use any refrigerant oil other 
than Double End Capped Polyalkylene Glycol (also known as “ULTRA PAG”) or Polyolester (also 
POE). 
 
Containers of DEC PAG or POE will absorb moisture if left open (hygroscopic). Keep containers 
tightly capped when not in use and keep all system components capped while servicing system. 
 
The oil charge is continuously circulated by the refrigerant during the operation of the system. A 
quantity of oil is trapped by the compressor, as well as by other parts of the system. 
 
The following chart may be used to calculate the amount of oil to be added in case a component is 
being replaced with a new part.  
 
 
Component Oil Amount 
Compressor See Instructions  
Evaporator 1.0 oz. per evaporator 
Condenser 1.5 oz. 
Receiver Drier 1.5 oz. 
Hose - Vapor 1.0 oz. per 10 foot 
Hose – Liquid 1.0 oz. per 20 foot 
 
Compressor  Replacement – To  properly  calculate  the  amount  of  oil required  in  the 
replacement  compressor,  it  is  necessary  to  pour  the  oil  out  of  the  old  compressor  into  a  clean 
container. Drain the oil out of the fill plug hole and then pour oil out of the suction and discharge 
ports while rotating the center shaft clockwise. Measure the total amount of oil removed from the 
old  compressor.  Add  ½  oz.  to  the  total  measured  to  account  for  unrecoverable  oil  in  the  old 
compressor. This  total  is  what  is  needed  in  the  new  compressor.  New  compressors come from 
Air Comm charged with 8 oz. (237 cc) of oil. This should be adjusted according to the amount of 
oil recovered from the old compressor and any other components being replaced. The receiver 
drier should always be replaced when the compressor is replaced or when the system has been 
open for an appreciable time, which accounts for another 1.5 oz. of oil that should be added. 
 
Below is an example of a compressor (and receiver drier) replacement for illustration: 
 
Evacuating the system recovers 1.5 oz. of oil.  Draining the old compressor recovered 2.0 
oz.  of  oil.    Adding  0.5  oz.  of  residual  unrecoverable  oil  in  the  compressor  gives  2.5  oz. 
The  new  receiver/drier  requires  an  additional  1.5  oz.,  plus  1.5  oz.  lost  when  the 
refrigerant  was  evacuated  from  the  system.  So  the  total  oil  needed  in  the  replacement 
compressor  for  this  case  is  5.5  oz.  Since  the  new  compressor  comes  with  8  oz.  of  oil, 
remove  the  oil  fill  plug  and  pour  out  2.5  oz.  of  oil.    Torque  compressor  oil  fill  cap  to  132-
216 in-lb. 
 
The  total  system  oil  charge  is  8.0  fl.  oz.  (237  ml.)  of  Refrigerant  Oil.  The  compressor  is 
charged with 8.0 fl. oz. of oil at the factory.