AirComm Corporation Bell 412 Air Conditioner Instructions for Continued Airworthiness User Manual

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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If a leak is detected at an O-ring fitting; check to ensure proper torque has been applied 
to the fitting. If the system continues to leak, reclaim the system of refrigerant, and install 
a new O-ring. NOTE: be sure that the O-ring is lubricated with refrigerant oil prior to its 
installation. 
 
A small amount of leakage (approximately one ounce per year) past the compressor 
shaft seal is normal. Most leak detectors are sensitive enough to show a leak of this 
magnitude. 
 
5. SUGGESTED EQUIPMENT REQUIRED FOR SERVICING 
 
Recovery / Recycling / Recharging Station 
Any model manufactured to comply with specification SAE J2788 
 
Electronic Leak Detector (R134a compatible) 
(Example: Micro-Tech III, Robinair, Snap-on, or equivalent). 
 
Manifold and gauge set (R134a compatible) 
(Example: Robinair, Snap-on, or equivalent). 
 
6. CONSUMABLE MATERIALS 
 
A. Refrigerant: 
This system is to be charged with Dupont, or equivalent HFC R134a refrigerant 
only. 
 
B. Lubricant:  - This system is to be serviced with Ultra PAG refrigerant oil. 
 
C. O-rings: 
As this system is charged with R134a refrigerant, it must be fitted with Highly 
Saturated Nitriles (HSN) O-rings. This system incorporates two different O-ring 
fittings, TORQ LOK® and Insert. The HSN O-rings for the TORQ LOK® fittings 
are BLACK in color and the HSN O-ring for the Insert fittings are GREEN in color. 
  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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7. SUGGESTED SPARES LIST 
 
Item Part Number 
 
Blower Motor  Fwd Evaporator ES61064-10 
Aft Evaporator ES61064-10 
 
Compressor Assembly 412AC-3542-2 
 
Compressor Drive Belt (Upper 7305 (412HP/EP) 
7312 (412/412SP) 
 
Compressor Drive Belt (Lower) 7355 (412HP/EP) 
7345 (412/412SP) 
 
Receiver / Drier Bottle ES43032-1 
 
Hi/Lo Pressure Switch ES57010-1 
 
By-pass Valve ES26194-6 
 
412AC-7058-16 Blower Motor & Fan replacement ES73131 
 (-1 New / –2 Overhauled) 
HSN O-rings; Insert type (Green) 
Size  
#6 O-ring ES44010-2 
#8 O-ring ES44010-3 
#10 O-ring ES44010-4 
 
HSN O-rings; TORQ LOK® Type (Black) 
Size 
#6 O-ring ES44012-2 
#8 O-ring ES44012-3 
 
 Speed Reducer Bearing ES33100-3 
 (Replaces obsolete  
 35BD219DUM) 
 
 
  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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CHAPTER 7 
STANDARD PRACTICES INFORMATION 
 
 
1. FITTING TORQUING PROCEDURES AND TORQUE VALUES 
 
INSERT O-RING FITTINGS TORQ LOK® FITTINGS 
 
Apply a thin coating of refrigerant oil to O-ring and Female side of fitting. 
 
Confirm there is no damage (nicks, dirt, etc.) on fittings. 
 
Slide B-nut back away from the end of the tube so you can see the O-ring as you slide 
the fitting together. 
 
Be careful not to pinch O-ring during assembly. 
 
Engage the male end into the female fitting being careful to maintain alignment. 
 
The male flange should seat fully against the female fitting without the O-ring being 
pinched. 
 
It is important to hold the fitting together while sliding the B-nut forward and engaging the 
threads. Tighten the B-nut by hand and then torque as follows. 
 
 Tightening specifications 
CAUTION: ALWAYS USE BACK UP WRENCH. EXCESSIVE TORQUE WILL DAMAGE 
THE JOINT, COMPROMISING THE INTEGRITY OF THE SEAL. 
 
Insert O-Ring Fittings (regardless of size): Hand tighten, then turn an additional 60 deg. 
(one flat on the nut). 
 
TORQ-LOK ® fittings (regardless of size): Hand tighten, then turn an additional 30 deg. 
 
 ALWAYS USE BACK UP WRENCH – DO NOT OVER TORQUE 
 
INSERT O-RING FITTINGS TORQ LOK® FITTINGS 
 
 
Once the system is charged, check each fitting with an electronic leak detector. 
(An electronic leak detector is the only reliable method of checking for refrigerant leaks)  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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Once the fittings have been checked and are found to be free of leaks, torque seal as 
appropriate. 
 
2. REMOVAL & REPLACEMENT OF THE CONDENSER BLOWER MOTOR & FAN 
ASSEMBLY 
 
 REMOVAL 
CAUTION 
It is recommended that the battery and external power be disconnected before starting work. 
 
A. Remove the upper transmission pylon cowling to gain access to the air conditioner 
condenser assembly. 
 
B. Remove and retain the screws from the condenser access panel located on the 
upper rear section of the condenser housing. (This will provide the necessary access 
to remove the blower motor and fan assembly) 
 
C. Disconnect the terminal leads from the blower motors that attach to the ES59120 RF 
Filter. These are located on each side of the aft lower section of the condenser 
frame. These wires will need to be pushed (one at a time) through the grommet on 
the blower housing. 
 
(View looking forward from back of condenser assy.) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 6:  Disconnect Terminal Leads from Motor 
 
D. Cut the safety wire attached to the three (3) motor mounting bolts on the 412AC-
7058-16 Vane Axial Blower. 
 
E. Remove and retain the motor mounting bolts and spacers holding the ES73131-X 
motor & fan assembly to the blower housing. 
 
CAUTION 
Be sure to support the blower fan & Motor assembly prior to removing the mounting bolts, this 
will prevent any damage to the stator vanes in-side the blower housing. 
Disconnect terminal leads 
from RF Filter. 
ES59120 RF Filter Condenser Frame 
Installation typical of both right and left side  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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CAUTION 
Do not attempt to remove the fan blade assembly from the motor. The fan blade is threaded to 
the motor armature shaft, and damage will occur if proper tooling is not available. 
 
F. Once the motor mounting bolts have been removed, the fan & motor can be removed 
as a complete assembly through the open condenser access panel in the rear of the 
condenser housing. 
 
CAUTION 
Care should be taken not to damage the aluminum fins inside the condenser housing when 
removing, or installing the blower fan & motor assembly. 
 
NOTE 
If the fins are bent or dented they must be combed out using a “Fin Comb Tool.” 
 
 
(View looking forward) 
 
Figure 7:  Condenser Access Panel 
 
G. Carefully package the ES73131 Fan & Motor assembly after its removal for shipping. 
Condenser Frame 
Condenser Access 
Panel 
Vane Axial Blower 
Assembly 
RF Filter  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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Figure 8:  ES73131 Fan & Motor Assembly 
 
INSTALLATION / REPLACEMENT 
 
A. Use the torque chart below for the re-installation of the blower mounting bolts. 
Torque each bolt in succession around the blower housing until all three torques 
have been achieved. 
 
B. Unpack the ES73131 Fan & Motor assembly to ready for installation. 
 
CAUTION 
Care should be taken not to damage the aluminum fins inside the condenser housing when 
removing, or installing the blower fan & motor assembly. 
 
NOTE 
If the fins are bent or dented they must be combed out using a “Fin Comb Tool.” 
 
C. Place the fan & motor assembly through the open condenser access panel in the 
rear of the condenser housing. 
 
D. Ensure the blower fan & motor assembly are in the proper location and position and 
hold in place.  This will require supporting the blower fan and motor.  
 
E. Reinstall the three (3) motor mounting bolts and three (3) spacers to hold the 
ES73131-X motor & fan assembly to the blower housing. 
 
F. Attach new safety wire to the three (3) mounting bolts on the 412AC-7058-16 Vane 
Axial Blower. 
 
G. Push the two (2) terminal leads through the grommets on the blower housing.  
 
H. Connect the terminal leads to the blower motors that attach to the ES59120 RF 
Filter. 
 
I. Reinstall the screws to the condenser access panel located on the upper rear section 
of the condenser housing. 
  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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J. Reinstall the upper transmission pylon cowling. 
 
Torque Chart 
 
Blower Part Number Torque Blower Mounting Bolts as Follows 
412AC-7058-16 1st Torque 2nd Torque 3rd Torque 
(ES73131) 30 in/lbs. 45 in/lbs. 60 in/lbs 
 
(Troubleshooting chart for ES73131 blower assembly is located in Chapter 7 of this manual.) 
 
* Contact the Air Comm Corporation Service Department for current price and availability for 
replacement of the ES73131 fan and motor assembly. 
 
 
3. REMOVAL, REPLACEMENT & ADJUSTMENT OF THE COMPRESSOR DRIVE 
BELTS 
 
 REMOVAL 
 
A. It is necessary to remove the aft transmission cowling to gain access to the Compressor 
Drive Belts for replacement and adjustment procedures. 
 
B. Cut safety wire on the Compressor Belt Tensioning link and the Belt Tensioning Bolt, 
and loosen and retain their respective Jam Nut(s). 
 
CAUTION 
Before attempting to adjust the lower drive belt tension, ensure that the speed reducer 
mount attaching bolts have been loosened. 
 
NOTE 
It is not necessary to loosen the speed reducer mounting bolts when replacing or adjusting 
the upper drive belt tension only. 
 
C. Loosen the tension on the Compressor Belt Tension link, and remove upper drive belt. 
(See Figure 9 below) 
 
NOTE 
To remove or replace the lower drive belt it is necessary to disconnect the forward end of the 
main transmission drive shaft coupling. 
(See BHT Service Manual for Instructions) 
 
NOTE 
It is acceptable to place balance weights on the aft side of the coupling bolts. 
 
D. Turning the Belt Tensioning Bolt Clock-wise (ensure that the speed reducer mounting 
bolts are loose) will loosen the belt tension, and allow the lower drive belt to be removed.  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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 INSTALLATION / REPLACEMENT 
 
CAUTION 
Before attempting to adjust the lower drive belt tension, ensure that the speed reducer 
mount attaching bolts have been loosened. 
 
NOTE 
To replace the lower drive belt it is necessary to disconnect the forward end of the main 
transmission drive shaft coupling. 
(See BHT Service Manual for Instructions) 
 
A. Replace the lower drive belt and turn the belt tensioning bolt counter clockwise to 
tighten (ensure that the speed reducer mounting bolts are tightened as well). 
  
B. Install the upper drive belt. 
 
C. Tighten the tension on the compressor belt tension link. 
 
D. Reinstall the belt tensioning bolt and jam nut(s). 
 
E. Install safety wire on the belt tensioning link and belt tensioning bolt. 
 
F. Re-torque the speed reducer mounting bolts to 95-110 inch lbs. 
 
G. Re-torque the compressor mounting bolts to 95-110 inch lbs.  
 
H. Replace the aft transmission cowling when installation and adjustments are 
completed. 
 
 
 ADJUSTMENT 
 
NOTE 
Proper belt tension is important to ensure a long belt service life and to avoid excessive loads 
on the compressor, and speed reducer bearing assemblies. 
 
NOTE 
When adjusting or replacing the drive belts, tension the lower belt first. 
 
A. The correct belt tension for the upper and lower 3/8” (10mm) belt is 61 lbs. (24.6 kg.)  
B. This can be achieved with the aid of a belt tensioning tool (this is the preferred method of 
obtaining proper belt tensioning). 
 
C. An alternate method is to observe a .13” (3.3 mm) belt deflection when 6 lbs (2.7 kg.) 
for new belts and 4 lbs. (1.8 kg.) for used belts of pressure is applied to the midpoint 
of the belt span. 
  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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NOTE 
The belt tension should be checked, and re-adjusted, if necessary after the first two hours of 
operation for a newly installed belt. 
 
 
 
Deflection should be 0.13” (3.3mm) 
Apply 6 lbs (2.7 kg) at midpoint 
4 lbs (1.8 kg) for used belts  
						

							AIR CONDITIONER SERVICE MANUAL 412AC-208M 
 
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Figure 9:  COMPRESSOR DRIVE ILLUSTRATION
NOTE: Use aft 
coupling bolts for shaft 
balance adjustment 
when A/C compressor 
pulley is installed.