1. Second Stage

2. Please Turn Off The Cell Phones

3. ©2006 Aqua Lung International, Inc
Copyright Notice
This program is copyrighted, all rights reserved. It may not in
whole or in part, be copied, photocopied, reproduced
translated, or reduced to any electronic medium or machine
readable form without prior consent in writing from Aqua Lung
International. It may not be distributed through the internet or
computer bulletin board systems without prior consent in
writing from Aqua Lung International
©2007 Aqua Lung International, Inc
Kronos 2nd Stage Service Program
©2006 Aqua Lung International, Inc

4. O-ring Removal (Pinch Method)
Pinch Method: Using fingers, push on opposite sides to create protrusion
Use only brass or plastic pics to remove o-rings, this will protect delicate seating surfaces
Never reuse o-rings
P/n

5. Product Features
Go directly
to disassembly

6. Features Pneumatically Balanced Second Stage Dual-Cam Controller
Asymmetrical Side-X Exhaust
EN 250 Coldwater Approved
Nitrox Compatible to 40%

7. Features (Balanced) Pneumatically Balanced Second Stage
For increased performance at any depth or cylinder pressure

8. Features (Dual-Cam) Dual-Cam Controller
Combined venturi and breathing resistance control for fast and simple diver adjustments

9. Features (Side-X Exhaust)
Asymmetrical Side-X Exhaust
Routes bubbles out of your viewing area
Directs warm exhaled air over the 2nd stage valve for increased freezing resistance

10. Exhausting!

11. Features (Coldwater)
The Kronos 2nd stage is EN 250 approved for cold water use when used with the Kronos Supreme model 1st stage
Due to the Side-X exhaust, exhaled gases warm the mechanism as it goes through the baffle

12. Features (Nitrox)
The Kronos is nitrox (EAN) compatible to 40% out of the box
Built with a high level of cleanliness
EAN compatible components and lubricants
Have passed required adiabatic compression testing to ensure their safety and compatibility

13. Features (Nitrox)
Responsibility of the owner to maintain the cleanliness of the regulator
If regulator will be used interchangeably with breathing air, the air should be oxygen-compatible or “hyper-filtered” whereas the condensed hydrocarbons do not exceed 0.1 mg/m3
Grade E air does not necessarily meet this criterion
Hydrocarbons found in Grade E air can pose a risk in the presence of elevated oxygen content

14. Features (Nitrox)
Hydrocarbons build up over time along the passageways of the equipment
When hydrocarbons come in contact with high-pressure oxygen enriched air, they can pose a very real hazard that can lead to combustion
If a regulator has had use with Grade E breathing air, it should receive a standard overhaul, including ultrasonic cleaning with a detergent solution, that removes hydrocarbons, prior to being put back into nitrox service

15. Features (Nitrox)
Although second stage components are not exposed to high pressure EAN, Aqualung recommends that the same cleaning procedures be followed for the complete regulator
This prevents the possibility of cross contamination and guarantees the cleanliness of the entire regulator

16. Disassembly

17. Remove Exhaust Cover Use small bladed screwdriver
Lift up on end of cover
Peel cover off by hand
Slide down hose

18. Remove MP Hose
Use two 11/16” open end wrenches

19. Remove Hose O-rings

20. Inspect Hose Crimps

21. Remove Cover Ring Use adj. face spanner (p/n:129198)
Lift out purge cover

22. Remove Retaining Ring Use retaining ring tool (p/n:129001)
Lift out washer and diaphragm

23. Remove Plug & O-ring
Use retaining ring tool to remove plug

24. Remove Venturi Clip Locate red clip Use a small bladed screwdriver
Carefully lift clip out of groove in venturi

25. Remove Venturi
Remove venturi O-ring

26. Remove Cam by Hand
Reverse thread
Turn cam clockwise to remove

27. Remove Fine Adjustment Screw
Use small 2.5mm bladed screwdriver
Remove O-ring

28. Remove Shuttle Valve Assy

29. Separate Shuttle Valve Assy

30. Remove MP Seat & O-ring

31. Inspect Counter-Balance Chamber
Inside sealing area

32. Remove Heat Exchanger & O-ring
Use 11/16” wrench

33. Slide Out Valve Body
Hold lever down

34. Remove Crown Use a medium bladed screwdriver
Loosen crown 6-7 turns to disengage threads
Carefully push out crown with seat tool (p/n:109437)

35. Remove Crown O-ring

36. Critically Inspect Crown
Sealing area
O-ring groove

37. Remove Lever (optional)

38. Inspect Lever

39. Straighten Legs If Necessary

40. Remove Mouthpiece Lift up and remove mouthpiece clamp
Pull off mouthpiece
Inspect mouthpiece for any holes or tears and replace if needed

41. Inspect Exhaust Valve
Replace if necessary

42. Technician Features No o-ring on valve body
New counter-balance chamber
New diaphragm and lever
Reverse thread on cam
Wrench flats on cam that engage with venturi. This allows venturi adjustment to increase or decrease spring tension (DUAL CAM)
Red clip holding venturi in place
Side-X exhaust cannot be completely removed without first removing mp hose

43. This Concludes Disassembly

44. Cleaning & Lubrication
Go directly to Reassembly

45. Cleaning Procedures Brass and Stainless Steel Parts
Pre-clean in warm soapy water; nylon bristle brush
Ultrasonically clean with soapy water; vinegar OK on tough corrosion
Rinse in fresh water; use distilled water if tap water is “hard”
Blow dry with lp hydrocarbon free gas (for EAN use)

46. Cleaning Procedures Aluminum, Plastic & Rubber Parts !
Soak in warm, soapy water
Use soft nylon bristle brush to remove deposits
Rinse with fresh water
Blow dry with LP hydrocarbon free gas (for EAN use)
CAUTION: DO NOT soak plastic parts in acidic solutions !

47. Cleaning Procedures Regulator Hose
Hose fittings - Ultrasonically clean with soapy water; vinegar OK on tough corrosion
Can run soapy water through hose if needed
Thoroughly rinse with fresh water
Blow out hose before installing

48. Lubrication Procedures
Christo-lube MCG 111
Light film only
Remove visible excess
If regulator will be used with EAN, you should wear powderless, latex gloves (or equivalent) when lubricating and handling o-rings

49. Reassembly

50. Replace Exhaust Valve Insert new exhaust valve thru center hole
Make sure barb is all the way thru
Using side cutters
Leave 5mm end after trimming
Barb

51. Install Crown O-ring

52. Insert Crown Into Valve Body
Use crown/lever adj tool (p/n )
Screw in crown until tool disengages

53. Install Valve Body into Case

54. Install O-ring & Heat Exchanger

55. Torque Heat Exchanger Tighten heat exchanger by hand until snug
Torque: in/lbs Nm
Use in/lb torque wrench & 11/16” crow-foot
Torque to 45 in/lbs (5 Nm)

56. Install O-ring & MP Seat

57. Assemble Shuttle Valve Assy

58. Install Shuttle Valve Assy
Make sure lever is perpendicular to valve body
With shuttle valve feet facing down & away from lever, slide assy into valve body

59. Install Cam into Valve Body
Turn cam counter-clockwise to install
Turn in by hand until it stops

60. Install Venturi O-ring
Make sure O-ring is placed into correct groove

61. Slide Venturi onto Tool
Use crown/lever tool
Slide venturi onto tool

62. Install Venturi Engage tool with cam
Turn tool counter-clockwise until cam stops turning
Turn tool back clockwise ¼ turn and hold in place

63. Install Venturi Slide venturi into place in the plus + position
Make sure the octagonal flats on the cam and the lever match up before pushing the venturi into place

64. Confirm Proper Installation
Make sure flat edge of cam is mm below flat edge of venturi
Flat edge of venturi
Flat edge of cam

65. Confirm Proper Installation
Press on lever to confirm proper return of lever

66. Insert Clip Into Groove

67. Install O-ring & Adj Screw
Use small bladed screwdriver
Screw in until adj screw is flush & O-ring is not visible

68. Adjusting

69. Adjust Lever Height Attach inline adj tool (p/n 100190) to 2nd stage
Attach to a properly adjusted 1st stage or test bench, slowly Pressurize to 3000 psi

70. Adjust Lever Height (max)
Use the crown/lever tool
Place the tool onto the case in the max position, (larger raised part facing down)
Slide tool across lever
2nd stage should leak air with this test
If 2nd stage does not leak, lever is to low
Raise lever height by backing out crown slightly and recheck

71. Adjust Lever Height (min)
Use the crown/lever tool
Turn the tool over & place onto the case slide tool across lever
2nd stage should not leak air with this test
If 2nd stage does leak, lever is to high
Lower lever height by turning in crown slightly and recheck

72. Set Adjustment Screw
While still under pressure, loosen adj screw until small leak is heard
Turn adj screw back in 1.5 turns
Depressurize & remove inline tool
CAUTION: If no leak is heard, cam was not installed correctly !

73. Install O-ring & Cap

74. Install Mouthpiece
Place mouthpiece onto oral boss with bridge facing up

75. Install Mouthpiece Clamp
Make sure buckle is facing heat exchanger
Buckle

76. Install Diaphragm & Washer

77. Install Retaining Ring
Use retaining ring tool to tighten ring

78. Install Purge Cover Check alignment of purge cover
If cover is not aligned properly, tighten or loosen retaining ring slightly to allow proper position of purge cover

79. Install Cover Ring

80. Install MP Hose Slide hose thru exhaust cover
Install hose onto heat exchanger hand tight

81. Tighten MP Hose Use torque wrench and 11/16” crow foot
While holding heat exchanger steady with 11/16” open end wrench, torque MP hose to 40 in/lb (4.5Nm)
Torque: in/lbs Nm

82. Install Exhaust Cover Slide exhaust cover into place
Inspect cover for proper seating

83. Install Exhaust Cover
Push cover onto holding pin
Push here

84. Final Testing

85. Final Testing
Attach 2nd stage to a properly adjusted 1st stage or test bench, slowly pressurize to 3000 psi (232 bar)

86. Final Testing Specifications at 2500-3000 psi (160-232 bar)
Medium pressure: psi (9-10 bar)
Opening effort: in/H2o ( mbar)
Opening Effort: in/H2o mbar

87. Final Testing Check for leaks Immerse second stage U/W
Look for streaming bubbles; don’t mistake trapped air for leaks
Note leak source; refer to troubleshooting table in service manual
NOTE: Do not confuse bubbles from trapped air with a true leak. If there is an air leak, bubbles will come out in a constant stream.

88. This Concludes Servicing Of The Kronos 2nd Stage
Rev 07/10/07