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...

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...

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...

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...

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...

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...

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...

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...

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.