Preliminary Requirements

Procedure

1. SUBTASK 72-32-03-350-100 Remove the Terminal Assembly from the Thermocouple

   1. Refer to Figure.

   2. Remove the terminal assembly from the fan frame assembly and cut the wires.

2. SUBTASK 72-32-03-750-001 Do the Continuity Test

   1. Refer to Figure and Figure.

   2. Connect the lamp and battery tester - 4.5 volts and sensing cover in turn.

      1. Use lamp and battery tester - 4.5 volts.

   3. Make sure the lamp comes on which shows contimuity.

   4. Replace the thermocouple assembly, if the lamp does not come on which shows continuity.

3. SUBTASK 72-32-03-330-001 Remove the Damaged Thermocouple from the Fan Frame Assembly

   1. Refer to Figure and Figure.

   2. Remove the damaged thermocouple without any damage to the fan frame.

   3. Remove the remaining compound from the block.

      1. Use a scraper.

         Use CoMat 05-019 WATERPROOF SILICON CARBIDE and CoMat 05-020 WATERPROOF SILICON CARBIDE.

4. SUBTASK 72-32-03-360-051 Prepare the Mating Surface for the Cold Curing Silicone Compound

   1. Refer to Figure.

   2. Cold liquid degrease the mating surfaces of the new thermocouples and block.

      1. Refer to the SPM TASK 70-11-26-300-503 and SPM TASK 70-36-02-360-501.

   3. Clean the mating surface with garnet paper and a small brush.

      1. Use CoMat 05-017 GARNET PAPER, 60 GRIT or CoMat 05-016 GARNET PAPER, 80-GRIT.

         Refer to the SPM TASK 70-36-02-360-501.

   4. Do step A again.

5. SUBTASK 72-32-03-360-052 Apply and Cure the Cold Curing Silicone Compound

   1. Refer to Figure.

   2. 
      CAUTION
      DO NOT EAT ANYTHING OR SMOKE AT LOCATIONS WHERE THESE MATERIAL ARE USED.
      
      CAUTION
      AFTER PREPARATION THE MATING SURFACES MUST BE FULLY CLEANED AND MUST NOT BE TOUCHED BY HAND, TO PREVENT CONTAMINATION.

      NOTE

      The primer must be applied immediately after the mating surfaces are prepared. It is cured at room temperature.

      If the parts are not used immediately after the primer is applied, they must be kept in polythene bags, but for not longer than 24 hours.

      Apply a thin layer of primer only to the prepared mating surface on the collar of the new thermocouple and the bore of the block. Dry in air for 30 minutes.

      1. Use CoMat 08-014 PRIMER, SILICONE ADHESIVE/SEALANT.

         Refer to the SPM TASK 70-36-02-360-501.

   3. Apply the cold curing silicone compound to each of the mating surfaces.

      1. Use CoMat 08-013 COLD CURING SILICONE COMPOUND.

         Refer to the SPM TASK 70-36-02-360-501.

   4. Install the new thermocouples in the fan frame through the blocks in not more than three minutes after the compound is applied.

      1. Apply sufficient pressure to ensure good contact and to form a witness of adhesive at all edges.

         Make sure that compound can be seen around the sealed surfaces.

   5. Cure the compound at 68 deg F (20 deg C) for 48 hours.

      1. Do not apply a load during this time.

   6. NOTE

      The parts can be touched after 12 hours.

6. SUBTASK 72-32-03-350-101 Install the Thermocouple to the Fan Frame Assembly

   1. Refer to Figure.

   2. Pull out the jackets of the new thermocouple to prevent looseness of the wire in the tube.

   3. Apply the cold curing silicone compound into the block connector to fix the jackets.

      1. Use CoMat 08-013 COLD CURING SILICONE COMPOUND.

         Refer to the SPM TASK 70-36-02-360-501.

   4. Wind together all the Alumel wires and also wind together all the Chromel wires of each thermocouple.

   5. Connect the wound together Alumel wires to the Alumel socket and also connect the wound together Chromel wires to the Chromel socket of the new terminal assembly with the use of a crimping tool.

   6. NOTE

      The wires are identified as follows:

      Alumel wire - red color.

      Chromel wire - yellow color.

      The sockets are identified on the terminal assembly T2.5 CM as follows:

      Alumel socket - AL.

      Chromel socket - CR.

      Fill the block connector with cold curing silicone compound.

      1. Use CoMat 08-013 COLD CURING SILICONE COMPOUND.

         Refer to the SPM TASK 70-36-02-360-501.

   7. Install the terminal assembly (01-500) and the bracket (01-495) to the block connector using two bolts (01-510).

   8. Torque the bolts between 36 and 45 lbfin (4.00 and 5.00 Nm).

      1. Use a standard torque wrench.

   9. NOTE

      When you install the terminal assembly to the block connector, the Chromel stud must be located to the No. 10 strut side of the fan frame assembly.

      When you put the wires into the block connector, wind the wires into a coil.

      Do the resistance check of the installed thermocouple.

      1. Do the insulation resistance check between the thermocouple and the fan frame assembly. The insulation resistance value must be a minimum of five megohms.

      2. Do the loop resistance check between the Alumel stud and Chromel stud. The loop resistance value must be 0.4 to 1.8 ohms at room temperature.

Figure: Removal of thermocouples

Removal of thermocouples



Figure: Installation of thermocouples

Installation of thermocouples