As problem of title, I have received the problem report from quality assurance department.

I would like to inform about problem report detail.

  • Problem detail
    Product ; ARTG45LHTA
    Quantity ; 2(Serial is T008921 and unknown)
    Problem contents ;
    Freezing was occurred at distributor.
    Technician found the contamination at inside of distributor.
  • Analysis result.
    <Analysis result of sample parts>
    *There was same issue at Australian market.(GS13-224))(foreign contamination was insulation.)
    　 FGL could not find the cause that insulation was included in distributor.
    But, they had already done the measure by additional of process validation.(27th December 2013)

    *This unit had been manufactured before measure had done.
    Foreign contamination was insulation (same as previous issue).

    Sample distributor Foreign contamination(insulation) Enlarged view

    <Investigation of manufacturing process at manufacturer (OKAYAMA)>
    *Manufacturer don’t use the insulation
    *Manufacture is manufacturing the distributor according to standards(Appendix 1)

    <FGT analysis result>
    1) Investigation of manufacture record at this product.
    * Repair history is nothing.(Appendix 2)

    2) Confirmation of manufacturing process at FGT

Work process

Manufacturing process of Heat exchanger assy

Work process

Manufacturing process of Heat exchanger assy

1

 Fitting of coupling pipe assy

8

 Leak check

2

 Welding of coupling pipe assy

9

 Confirmation of residual pressure by helium gas
 　

3

 Fitting of distributor assy

10

 Paste INS(PIPE) B , 14B 

4

 Welding of distributor assy

11

 Paste Seal (PIPE) A , B

5

 Remove flare nut. and, fitting coupler.

12

 Remove coupler

13

 Confirmation of Foreign contamination

6

 Vacuuming 

14

 Do the visual inspection

7

 Fill the helium gas
(1.2 ±0.2 MPa)

15

 Fitting flare nut(70±10kgf.cm)
  • * Seal(Pipe)A,B is same material as this time’s foreign contamination.
    this material is too large. Therefore, worker cannot insert it from half union.
  • Speculation of this result’s cause
    * FGL guess that there is possibility that the worker of FGT had inserted this foreign contamination at half union.
    (The place that there is possibility to be inserted foreign contamination is only this place.)
    After then, foreign contamination had moved to distributor part by refrigerant flow.
  • Measure
    Add to process validation as contamination.
    *This process is carrying out now.(from 27th December 2013)(Appendix 4, 5)
  • Measure to product
    Already installed product; measures by each location if problem is occur.
    Stock product; No measures. FGL think this problem will not happen often.
    Manufacture product ; already measured.