Apeks XL4 SECOND STAGE User manual

TECHNICAL SUPPORT
APEKS MARINE EQUIPMENT LTD, NEPTUNE WAY, BLACKBURN, LANCASHIRE. BB1 2BT
Tel: [phone] Fax: [phone] E-mail: [email protected] Web: www.apeks.co.uk
MAINTENANCE MANUAL
FOR
AUTHORISED TECHNICIANS
Document No. AP5840
Issue 1
13/11/2017
XL4 SECOND STAGE
REGULATOR

2
XL4 2nd Stage Maintenance Manual
AMENDMENTS RECORD:
Amendments and approval of this document can only be carried out by the relevant people listed on the Approved list of
signatures, which is listed in the Apeks Quality Manual. To instigate a change, a Task / Change request form, (Form No.
‘DESI/10002’), must be completed and passed to the relevant person(s) for approval which are listed on the Approved List of
Signatures. When approval has been granted and recorded this table can then be completed and the document up issued.
Change
No.
Change
Request No.
Description & Comments: Change
Date
New Issue
No.
Changed
By:
Approved
By:

3
XL4 2nd Stage Maintenance Manual
COPYRIGHT NOTICE.............................................................................................................................................4
INTRODUCTION......................................................................................................................................................4
WARNINGS, CAUTIONS & NOTES.......................................................................................................................4
SCHEDULED SERVICE..........................................................................................................................................4
HOSE INSPECTION & CLEANING PROCEDURE...............................................................................................4
GENERAL GUIDELINES.........................................................................................................................................5
GENERAL CONVENTIONS.....................................................................................................................................5
DISASSEMBLY PROCEDURES.............................................................................................................................5
INSPECTION PROCEDURES.................................................................................................................................8
REASSEMBLY PROCEDURES..............................................................................................................................9
FINAL TESTING.....................................................................................................................................................12
TABLE 1 - TROUBLSHOOTING GUIDE..............................................................................................................14
TABLE 2 - RECOMMENDED TOOL LIST............................................................................................................15
TABLE 3 - RECOMMENDED LUBRICANTS & CLEANERS.............................................................................16
CLEANING AND LUBRICATION PROCEDURE.................................................................................................18
TABLE 4 -TORQUE SPECIFICATIONS................................................................................................................18
TABLE 5 - TEST BENCH SPECIFICATIONS.......................................................................................................18
XL4 EXPLODED PARTS DRAWING....................................................................................................................19
Contents

4
XL4 2nd Stage Maintenance Manual
4
WARNINGS indicate a procedure or situation
that may result in serious injury or death if
instructions are not followed correctly.
CAUTIONS indicate any situation or
technique that will result in potential
damage to the product, or render the
product unsafe if instructions are not
followed correctly.
NOTES are used to emphasise important points,
tips, and reminders.
WARNINGS, CAUTIONS & NOTES
Pay special attention to information provided in warnings,
cautions, and notes that are accompanied by one of these
symbols:
COPYRIGHT NOTICE
This manual 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 Apeks
Marine Equipment Ltd. It may not be distributed through the
internet or computer bulletin board systems without prior
consent from Apeks Marine Equipment Ltd.
©2017 Apeks Marine Equipment Ltd.
XL4 Second Stage Maintenance Manual
(AP5840 Issue 1 )
INTRODUCTION
This manual provides factory prescribed procedures for
the correct maintenance and repair of the Apeks XL4
second stage regulators. It is not intended to be used
as an instructional manual for untrained personnel. The
procedures outlined within this manual are to be performed
only by personnel who have received factory authorised
training through an Apeks Service & Repair Seminar. If
you do not completely understand all of the procedures
outlined in this manual, contact Apeks to speak directly with
a Technical Advisor before proceeding any further.
It is recommended that the Apeks XL4 2nd Stage regulator
should be examined annually regardless of usage.
A full service should be performed every two years.
However, If you are at all unsure about the correct
functioning of the Apeks XL4 2nd Stage then it must be
ofcially inspected immediately.
All service and inspection details need to be documented to
keep the Limited Lifetime Warranty in effect.
A Second Stage Ofcial Inspection
consists of:
1. Checking the lever height with setting tool.
2. Checking for opening effort that is within the
acceptable range.
3. A pressurised immersion test of the entire unit to check
for air leakage.
4. A visual inspection of the exhaust valve(s) to see that
they are in good condition and that it is seating against
a clean and undamaged surface.
5. Pulling back hose protectors and checking that the
hoses are secure in the hose crimps.
6. A visual inspection of the mouthpiece looking for tears
or holes and checking the general condition.
If a regulator fails steps 1,2 or 3 the entire regulator should
be serviced. If a regulator fails step 4 it will be up to the
technician’s discretion whether or not a full service is
required. Failure of step 5 or 6 requires replacement of the
part.
HOSE INSPECTION & CLEANING
PROCEDURE
Please refer to separate
document labelled “Hose
Inspection & Cleaning
Procedure” for full details
of the maintenance of
hoses which can be found
in the Technical section of
the Apeks website.
SCHEDULED SERVICE

5
XL4 2nd Stage Maintenance Manual
NOTE: Before performing any disassembly, refer
to the exploded parts drawing, which references
all mandatory replacement parts. These parts
should be replaced with new, and must not be
reused under any circumstances - regardless of
the age of the regulator or how much use it has
received since it was last serviced.
CAUTION: Use only a plastic, brass or
aluminium ‘O’ Ring removal tool (PN AT79)
when removing ‘O’ Rings to prevent damage
to the sealing surface. Even a small scratch
across an ‘O’ Ring sealing surface could
result in leakage. Once an ‘O’ Ring sealing
surface has been damaged, the part must
be replaced with new. DO NOT use a dental
pick, or any other steel instrument.
Pinch Method
Press upwards
on sides of ‘O’
Ring to create a
protrusion. Grab
‘O’ Ring or insert
‘O’ Ring tool at
protrusion.
1. In order to correctly perform the procedures outlined in
this manual, it is important to follow each step exactly
in the order given. Read over the entire manual to
become familiar with all procedures and to learn which
specialty tools and replacement parts will be required
before commencing disassembly. Keep the manual
open beside you for reference while performing each
procedure. Do not rely on memory.
2. All service and repair should be carried out in a work
area specically set up and equipped for the task.
Adequate lighting, cleanliness, and easy access to
all required tools are essential for an efcient repair
facility.
3. During disassembly, reusable components should
be segregated and not allowed to intermix with non
reusable parts or parts from other units. Delicate parts,
including inlet ttings and valve seats which contain
critical sealing surfaces, must be protected and
isolated from other parts to prevent damage during the
cleaning procedure.
4. Use only genuine Apeks parts provided in the 2nd
stage service kit (AP0219). DO NOT attempt to
substitute an Apeks part with another manufacturer’s,
regardless of any similarity in shape or size.
5. Do not attempt to reuse mandatory replacement
parts under any circumstances, regardless of the
amount of use the product has received since it was
manufactured or last serviced.
6. When reassembling, it is important to follow every
torque specication prescribed in this manual, using
a calibrated torque wrench. Most parts are made of
either marine brass or plastic, and can be permanently
damaged by undue stress.
Unless otherwise instructed, the following terminology and
techniques are assumed:
1. When instructed to remove, unscrew, or loosen a
threaded part, turn the part anti-clockwise.
2. When instructed to install, screw in, or tighten a
threaded part, turn the part clockwise.
3. When instructed to remove an ‘O’ Ring, use the pinch
method (see gure below) if possible, or use a brass,
aluminium or plastic ‘O’ Ring removal tool. Avoid using
hardened steel picks, as they may damage ‘O’ Ring
sealing surfaces. All ‘O’ Rings that are removed are
discarded and replaced with brand new ‘O’ Rings.
4. The following acronyms are used throughout the
manual: MP is Medium Pressure; HP is High Pressure;
PN is Part Number.
5. Numbers in parentheses reference the key numbers
on the exploded parts schematics. For example, in the
statement, “...remove ‘O’ ring (11) from...”, the number
11 is the key number to the Inlet Fitting ‘O’ Ring.
GENERAL GUIDELINES GENERAL CONVENTIONS
DISASSEMBLY PROCEDURES

6
XL4 2nd Stage Maintenance Manual
Removal of Mouthpiece
CAUTION: Take care not to damage or distort
the Lever (15) when removing the Venturi
Lever (9). DO NOT depress the tab of the
Venturi Lever too far, as this will result in
permanent deformation.
Removal of hose
Removal of Exhaust Tee
Removal of Front Cover & Diaphragm
Removal of Venturi Lever & Spindle
3. Pull back the two Hose
Protectors (29) and inspect
the hose crimps. If either
crimp is damaged or the
hose is pulling out of the
crimp then the hose must
be replaced.
NOTE: Before starting reassembly refer to Hose
Inspection & Cleaning Procedure found on page 4.
2. Remove O Rings (17) and (28) from the hose (30).
Exercise caution not to scratch the O Ring groove in the
hose swivel.
1. Using a 13/16” spanner
hold the Inlet Shroud (18)
whilst undoing the hose
with an 11/16” spanner
(AT39).
4. Place one nger into
each side of the Exhaust
Tee (7) and squeeze them
together. Pull the Exhaust
Tee away from the Case
(13).
5. Unfasten the Mouthpiece Clip (12) and pull the
Mouthpiece off the Case(13)
6. To remove the XL4 Clamp Ring (1) place your thumb on
the top of the clamp ring as shown on the rst image below.
Grip the rest of the clamp ring and turn anti-clockwise.
Separate the Purge Clamp Ring (1) from the Purge Button
assembly and the Case (13).
NOTE: Failure to hold
the Clamp Ring as
outlined in section 6 may
result in the cover being
more difcult to remove
due pressure being
applied to the locking
mechanism.
7. Locate the three kidney shaped pegs of the AT71
Locking Ring Tool into the slots of the Inner Locking Ring
(4). Unscrew the Inner Locking Ring (4). Remove the
Friction Ring (5) and the Diaphragm (6) from inside of the
Case (13).

7
XL4 2nd Stage Maintenance Manual
8. To remove the Venturi Lever (9) from the Case (13),
position the lever vertically so that the tab is visible as
shown in the rst image below. Locate the venturi lever
removal tool (AT77) slot on the venturi lever, then press
down on the opposite side to push out the venturi lever.
9. Totally slide out the Venturi Lever (9) from the body (13).
Remove the ‘O’ ring (10) from the Venturi Lever (9) taking
care not to scratch the ‘O’ ring Groove.
10. Using a 13/16” Spanner
unscrew the Inlet Shroud
(18).
11. The Inlet Shroud assembly will remove as one. To
separate grip the 3/8” regulator hose thread on the Inlet
Shroud Fitting (20) and slide off the Inlet Shroud (18).
NOTE: There will be some slight resistance
removing the two parts above due to the O Ring
(19) underneath the Inlet Shroud (18).
12. Using a 5mm Hex Key (AT37) unscrew the Valve Seat
(16) from the Inlet Shroud Fitting (20). Once satised that
the thread has disengaged, the Valve Seat may need a little
push as the O ring will be holding it in the bore of the Inlet
Shroud Fitting. Remove O Rings (19) and (17).
NOTE: Hold the Inlet Shroud Fitting and unscrew
the Valve Seat clockwise.
13. To remove the spindle assembly from the Case (13) use
the opposite end of the cracking effort adjuster tool (AT76) to
push it out.
14. Once the Lever
assembly is free from
the Case (13) push it
backwards towards the
Venturi Lever hole, then lift
out as shown.
15. To remove the Lever
(15) from the Spindle
Body (14) screw the
AT48 tool into the spindle
to compress the spring.
Carefully pull one of the
legs out of the Valve Body
and then ease the second
leg out. Separate the
Shuttle Valve assembly
(22-27) as shown below,
making sure that the ‘O’
ring (25) is removed from
the Shuttle Valve (26).
NOTE: NOTE:
O-Ring (25) may
remain in the shuttle
valve (26) when
disassembled, make
sure it is removed
before proceeding.

8
XL4 2nd Stage Maintenance Manual
INSPECTION PROCEDURES
NOTE: Before performing any reassembly
procedures, some parts must be inspected. The
following section details the parts and areas that must
be checked.
The following parts should be checked for cracks,
deep scratches, excessive wear and tear and
distortion.
Sealing faces, grooves and bores should be checked
for scratches.
Purge Button Assembly (2) and (3)
Venturi Lever (9)
Spindle (14)
NOTE: Before starting reassembly refer to Hose
Inspection & Cleaning Procedure found on page 4.
Before starting reassembly, perform parts
cleaning and lubrication according to the
procedures outlined in ‘Cleaning & Lubrication’
on page 17.
This Ends Disassembly
NOTE: There is no
need to remove the
Micro Adjuster Screw
(21) from the Spindle
Adjuster Sleeve (22).
NOTE: If the
Exhaust Valve (8)
is to be removed,
pinch the edge of the
Valve and pull the tail
through the hole in
the Case (13).
16. Fold back the edges of the Exhaust Valve (8) and
inspect underneath. The seating surface should be clean
and free of damage. Inspect the Exhaust Valve. It should be
supple and have well dened edges. If it looks good, there
is no need to remove it and it may be reused. If there is any
sign of deterioration, it should be replaced.
1. Inspect the back face of
the Purge Button (2) and,
ensure that the Rubber
Purge Spring is rmly
located around the entire
perimeter of the Button.
2. Check that the tab of the
Venturi Lever (9) has not
been over stressed and
that it is level with the rest
of the lever.
3. Check that the Spindle
Body (14) is free from
scratches, cracks and
distortion. Look for
excessive wear around
the Lever holes. Check
that the thread is in good
condition.

9
XL4 2nd Stage Maintenance Manual
REASSEMBLY PROCEDURES
Assembling of the Spindle Body
CAUTION: Ensure that the Lever is not
twisted and that legs are parallel. Lever
should appear as that shown on the left, not
as shown on the right. If necessary, gently
squeeze legs together to straighten.
NOTE: Ensure that
the Lever has a full
range of movement
and does not catch
on the Valve Spindle
Body. Ensure that the
spring can be seen
through the Valve
Spindle Hole.
1. Carefully insert the Spindle Adjuster Sleeve (22) into
the Spindle Body (14). Ensure that two legs of the Spindle
Adjuster Sleeve correctly line up with the slots in the Body.
Check the Spindle Adjuster Sleeve is rmly pressed into the
end of the Body.
3. Install a new lubricated ‘O’ ring (25) onto the Spring
Carrier (23), followed by the Spring (24). Fit the Shuttle
Valve (26) onto the Spring Carrier and Spring, carefully
guiding the end of the Carrier into the bore of the Shuttle
valve.
2. Press the Shuttle Valve
(26) down rmly onto the
Silicone Valve Seat (27),
making sure it is fully
engaged.
CAUTION: Ensure the work surface is clean
and free from debris. DO NOT mark the face
of the Silicone seating, this will cause the 2nd
stage to leak when fully assembled.
4. Insert the Spring Carrier end of the assembly into the
Spindle Body (14). Screw in the AT48 tool to fully compress
the Spring until it passes the triangular shaped hole in the
Body.
5. Insert the feet of the Lever (15) into the gap, this retains
the Shuttle Valve inside the Body. Ensure the feet are
engaged fully in the Shuttle Valve (26) and the Lever is
parallel to the Spindle Body (14). Press down on the Lever
(15) to disengage the Silicone Seat (27) and remove the tool
AT48.
GAP
Fitting Spindle Assembly into Case
CAUTION: DO NOT use the lever to push
the Spindle into the case as this will bend the
lever.
6. Insert the Spindle Body
assembly into the Case.
Insert the Spindle Adjuster
side rst into the Venturi
Lever hole then slide back
so the Silicone Valve Seat
end engages into the Body
snug.
NOTE: The longer
lug on the underside
of the Spindle Body
(14) should engage
into the slot in the
Body (13).

10
XL4 2nd Stage Maintenance Manual
CAUTION: Ensure that the Diaphragm (6) and
Friction Ring (5) are seated correctly and are not
creased.
CAUTION:
Ensure that the
Lever (15) moves
freely and sits
vertically within
the case (13).
7. Using the opposite end of the Cracking Adjuster tool
(AT76) lined up with the Spindle Adjuster Sleeve (22) push
the Spindle Assembly rmly into the Case ensuring that
there is no gap between the two parts. Ensure that the
Lever has a full range of movement and does not catch on
the Valve Spindle Body.
NOTE: The square lug on the top side of the Spindle
Body (14) should engage into the slot in the Body (13).
8. Install a new Lubricated ‘O’ ring (17) onto the Valve Seat
(16) and O Ring (19) onto the Inlet Shrouded Fitting (20).
9. Carefully push the Valve Seat (16) into the larger diameter
bore of the Inlet Shrouded Fitting (20) threaded end rst.
Using a 5mm Hex Key (AT37) turn the valve seat counter
clockwise until it bottoms out.
10. Slide the Inlet Shroud (18) onto the Inlet Shroud Fitting
(20) hex side rst past the already installed O Ring.
11. Screw the Inlet Fitting assembly into the Spindle Body
(14) and torque to 3 Nm (2.2ft.lb) using a 13/16” socket.
NOTE: The 13/16” socket can be used on it’s own to
get a better grip when tting the Inlet Fitting assembly.
12. While holding the Case (13) at eye level, use a 5mm
Hex Key (AT37) to screw the Valve Seat (16) clockwise until
the Lever (15) drops just below the rim of the Case. Check
by gently icking the lever, it should bounce and have free
movement. The lever should return to its set position, if it
sticks then the lever is not square, tted incorrectly or it is
bent.
13. Ret the Diaphragm (6) into the front of the Case (13).
Using your nger carefully work the edges of the Diaphragm
into place so it sits evenly in the Case. Insert the Friction
Ring (5) into the case. Use the same technique to ensure it
sits evenly onto the Diaphragm.
14. Fit the Inner Locking Ring (4) ensuring the 3 small
grooves are facing up. (see pic below). Using the AT71 Tool
slowly screw the Inner Locking Ring into the Case. Hand
tighten only.
NOTE: Refer to section 7 on page 6 for Tool use
instructions.

11
XL4 2nd Stage Maintenance Manual
14 cont’d. Once the
diaphragm is secure,
gently grip the diaphragm
pad between the thumb
and forenger, and gently
pull from side to side to
check the diaphragm is
secure.
Final Assembly
Before starting Final Assembly, perform Final
Testing according to the procedures outlined in
‘Final Testing’ on page 12.
3. Install a new lubricated ‘O’ ring (10) onto the Venturi Lever
(9). Align the Venturi Lever in a vertical position with the
Case (13) and press the lever into place. Ensure that the
Venturi Lever rotates freely and feels secure.
NOTE: To check that the Diaphragm has sealed
correctly, place your thumb over the end of the Inlet
Fitting with the hose removed (see paragraph 1 in
disassembly to remove and paragraph 4 and 5 in nal
assembly to ret) . Suck and hold at the mouthpiece
port, a vacuum should be held without any leakage.
NOTE: The thumb
grip section of
the Venturi Lever
needs to t in the
grooved section
on the Case.
4. If equipped with a
Comfo-bite Mouthpiece,
make sure the ‘bridge’
of the Mouthpiece (11) is
facing upward. Stretch
the Mouthpiece over the
second-stage Mouthpiece
outlet port.
1. Place the Purge Button
(2) inside the Clamp Ring
(1) ensuring the three
locating tabs line up.
2. Fit the front cover assembly onto the case (13) roughly
at the 11 o’clock position then turn clockwise until the cover
locks rmly into position.
At the base of the Mouthpiece is a groove for the
Mouthpiece Clip (12). Wrap the Clip around the Mouthpiece
so that the buckle points toward the Hose. Fasten the Clip,
ensuring that the Mouthpiece (11) is securely held in place.
5. Locate the bottom of the Exhaust Tee (7) onto the Case
(13). Place a thumb in each exhaust port and push the Tee
towards the mouthpiece. Ensure that the Tee ts over the
Case and is secure. Taking care not to damage or dislodge
the Exhaust Valve (8).
NOTE: Ensure the
Exhaust Tee is
captured fully by
the Case
6. Fit O Ring (28) onto the rst stage end of the hose and O
ring (17) into the Hose Swivel end of the hose.
7. Screw the Hose onto
the second stage. Using
a 11/16” crowsfoot, torque
to 5Nm (3.7 ft/lb), holding
the Inlet Shroud (18) with a
13/16” spanner.
This Ends Reassembly

12
XL4 2nd Stage Maintenance Manual
FINAL TESTING
Setting the Lever Height
WARNING: Compressed air can be highly
explosive and is dangerous if misused.
Ensure the cylinder valve is opened slowly.
Use eye and ear personal protective
equipment when performing any tests
involving compressed air.
1. Attach an Inline
Adjustment Tool (AT72)
to a regulator hose on a
correctly set rst stage.
Refer to the appropriate
rst stage technical manual
before attempting to
perform any adjustments.
2. Screw the Inline
Adjustment Tool onto the
threaded end of the 2nd
stage. Attach the rst stage
to a cylinder containing
207 Bar (3000 psi). Slowly
open the cylinder valve and
pressurise the reguator.
NOTE: If the 2nd
stage is leaking
turn the inline
adjuster clockwise
until the leaking
stops.
3. Purge the 2nd stage
gently 2 to 3 times to check
there is air ow.
4. Place the “GAS FLOW” side of the testing puck section
on the Setting Tool (AT75) over the plastic pad of the
Diaphragm.There should be a ow of air, if not adjust the
inline adjuster counter clockwise in 1/16 turns until there is a
steady ow.
5. Turn the puck section of the adjustment tool (AT75) to the
opposite side “NO GAS FLOW” to check that the lever is set
correct and there is no ow of air.
CAUTION: The air ow should be continuous
with no uttering
NOTE: Keep the puck in place whilst making
adjustments
CAUTION: Free ow test should be done
every time the lever height has been adjusted.
NOTE: “NO GAS” will be visible when performing gas
ow setting.
NOTE: It is important to ensure that the rim of the
tool is concentric with the rim of the inner locking
ring throughout. Pressing on the plastic pad of the
Diaphragm with the tool misaligned will not measure
the purge button depth and therefore give incorrect
results.
NOTE: If there is gas ow, keep the puck on “NO GAS
FLOW” and turn the inline adjuster clockwise in 1/16
increments until the ow ceases. Turn the puck back to
“GAS FLOW” to make sure there is still air ow.
NOTE: “GAS FLOW” will be visible on the tool when
checking no gas ow.

13
XL4 2nd Stage Maintenance Manual
NOTE: Extremely small leaks may be better detected
by applying a soap solution or Snoop™ to the leak
area. Bubble streams will indicate the source of the
leak. Before disassembling to correct any leaks,
rinse the entire regulator thoroughly with fresh water
and blow out all residual moisture with ltered, low-
pressure air. Disassemble and remedy the problem,
referring to “Table 1 - Troubleshooting.”
Second Stage Opening Effort Test Immersion Test
1. Insert the Micro Adjuster Tool (AT76) into the open side of
the Case (13), making sure that the hexagonal bit engages
into the Micro Adjuster Screw (21). Connect the rst stage
regulator to a calibrated test bench and pressurise the
system to 207 bar (3000 psi). Slowly open the owmeter
control knob (start vacuum) while watching both the
magnahelic gauge and the intermediate pressure gauge.
1. After disconnecting
the regulator from the
ow bench, connect it
to a gas cylinder lled to
approximately 200 bar.
Open the cylinder valve to
repressurise the regulator,
and submerge the entire
system in a test tank of
clean water.
3. With the second stage
still attached to the
Magnehelic mouthpiece,
turn the supply off, the
vacuum gauge should read
above 100mm Hg (53.5” of
water)
2. With the Venturi Lever set to the + position tap the Purge
Button quickly, this should cause the regulator to freeow.
Stop the freeow after a couple of seconds by placing a
hand over the mouthpiece.
1. Depress the Purge Button (2) fully to ensure that an
adequate volume of air needed to clear the second stage
ows through the mouthpiece. Then, inhale slowly but
deeply from the mouthpiece. A properly serviced and
adjusted regulator should deliver air upon deep inhalation
without excessive inhalation effort, freeow, or “uttering” of
the second-stage diaphragm. When exhaling, there should
be no uttering or sticking of the exhalation valve. If any of
these problems occur, refer to “Table 1 - Troubleshooting”.
2. When the intermediate pressure begins to drop, indicating
the second-stage valve is open, the magnahelic gauge
should indicate an opening effort of +1.4 in.H2O (3.5 mbar)
to +1.6 in.H2O (4 mbar). If the reading is outside of these
specications, adjust the Micro Adjuster Screw (21), turning
anti-clockwise to lower the opening effort or clockwise to
increase the opening effort. If this fails to give the correct
reading refer to “Table 1 - Troubleshooting” for corrective
actions.
Subjective Breathing Test
NOTE: If the Magnehelic being used isn’t
tted with a vacuum gauge you will need to
perform the test orally. Place your thumb over
the inlet tting and inhale normally through
the mouthpiece. If you can draw air in or hear
air ow refer to the trouble shooting guide on
page 14.
2. Observe any bubbles arising from the submerged
regulator over a one minute period. The recommended time
is necessary due to slower bubble formation that occurs in
smaller leaks. Bubbles indicate a leak, which requires the
system to be disassembled at the source to check sealing
surfaces, assembly sequence and component positioning in
order to correct the problem(s).

14
XL4 2nd Stage Maintenance Manual
Table 1 - Troubleshooting Guide
SYMPTOM POSSIBLE CAUSE TREATMENT
Leakage or freeow from Flight
Second Stage
1. Excessively high rst-stage
intermediate pressure.
1. Refer to rst-stage
Troubleshooting Guide.
2. Silicone seating (27) damaged or
worn. 2. Replace with Silicone Seating.
3. Valve Seat (16) adjusted incorrectly,
Lever (15) set too high.
3. Reset Seat preliminary
settings, and repeat Adjustment
Procedures.
4. Lever (15) bent. 4. Replace Lever.
5. Valve Seat (16) sealing surface
damaged. 5. Replace Valve Seat.
6. Spring (24) damaged. 6. Replace Spring.
7. Shuttle Valve ‘O’ Ring (25)
damaged. 7. Replace ‘O’ Ring.
8. Shuttle Valve (26) bore damaged. 8. Replace Shuttle Valve.
9. Venturi Lever ‘O’ Ring (10)
damaged. 9. Replace ‘O’ Ring.
Low purge or excessive work of
breathing (full cylinder)
1. Low rst-stage intermediate
pressure.
1. Refer to rst-stage
Troubleshooting Guide.
2. Seat (16) adjusted incorrectly, Lever
(15) set too low.
2. Reset Seat preliminary
settings, and repeat Adjustment
Procedures.
3. Intermediate pressure hose clogged
or obstructed. 3. Clean or replace Hose.
4. Black rubber seating tted
4. Replace with silicone seating
and reset with AT75 setting tool
marked with letter ‘B’
5. Lever (15) bent or catching on Valve
Spindle (14). 5. Replace Lever.
Water entering Flight Second Stage
1. Mouthpiece (11) damaged or
incorrectly tted.
1. Replace or re-t Mouthpiece as
appropriate.
2. Diaphragm (6) damaged. 2. Replace Diaphragm.
3. Diaphragm (6) improperly seated in
Case (13).
3. Remove Purge Button assembly
and Inner Locking Ring (5),
properly reassemble Diaphragm
(check for distortion).
4. Exhaust Valve (8) damaged. 4. Replace Exhaust Valve.
5. Case (13) damaged. (Check exhaust
valve seating surface.) 5. Disassemble and replace Case.
6. Inlet Fitting ‘O’ Ring (19) damaged. 6. Replace ‘O’ Ring.
7. Venturi Lever (9) or ‘O’ Ring (10)
damaged. 7. Replace ‘O’ Ring.

15
XL4 2nd Stage Maintenance Manual
PART # DESCRIPTION APPLICATION IMAGE
AT48 1ST AND 2ND STAGE TOOL REMOVING / INSERTING LEVER
AT71 INNER LOCKING RING TOOL REMOVAL / INSERTING INNER
LOCKING RING
AT72 INLINE ADJUSTING TOOL LEVER HEIGHT SETTING
AT75 SETTING TOOL LEVER HEIGHT SETTING
AT76 ADJUSTMENT TOOL MICRO ADJUSTER SETTING /
REMOVAL AND FITTING SPINDLE
AT77 VENTURI TOOL REMOVING VENTURI LEVER
AT79 O RING TOOL O RING REMOVAL
AT39 11/16” SPANNER HOSE REMOVAL
N/A 13/16” SPANNER HOSE REMOVAL
N/A 13/16” SOCKET INLET FITTING
N/A TORQUE WRENCH INLET FITTING
AT37 5MM HEX KEY VALVE SEAT
N/A CYLINDER FINAL TESTING
Table 2 - Recommended Tool List

16
XL4 2nd Stage Maintenance Manual
Table 3 - Recommended Lubricants, Cleaning &
Disinfectant Solutions
LUBRICANTS APPLICATIONS SOURCE
Christo-Lube MCG111 All o rings. Oxygen Compatible Aqua Lung # 820466 or 480025 or
AP1495
PerFluroLube 20/1 All o rings. Oxygen Compatible Aqua Lung # AP1493
CAUTION: Silicone rubber requires no lubrication or preservative treatment. DO NOT apply grease or
spray to silicone rubber parts. Doing so may cause chemical breakdown, can change their molecular
construction and cause premature deterioration of the material
GENERAL CLEANING SOLUTIONS
Liquid dishwashing detergent
(diluted with hot water) *Soapy water
is dened as ‘household’ grade liquid
dishwashing detergent diluted in warm
water.
Degreaser for brass and stainless-
steel parts; general cleaning
solution for plastic and rubber parts
‘Household grade’
CAUTION: Do not place plastic and rubber parts in acid solutions. Doing so may alter the physical
properties of the component and cause degradation and premature breakdown.
White distilled vinegar (acetic acid,
50% warm water)
Acid bath for reusable stainless
steel and brass parts
‘Household grade’
OAKite #31 (diluted with warm
water to a maximum of 25%)
Acid bath for reusable stainless
steel and brass parts
Oakite Products, Inc.
NETALU (diluted with warm water
to a maximum of 25%)
Acid bath for reusable stainless
steel, brass and aluminium parts
Aqua Lung ref# 455001
CAUTION: Do not use hydrochloric acid, (muriatic acid, spirit of salt), for the cleaning of any parts.
Even if strongly diluted, hydrochloric acid can harm the coating of metal parts and leaves a corrosive
deposit that is harmful and damages plastic parts and O-ring seals.

17
XL4 2nd Stage Maintenance Manual
WARNING: Never use solvents to clean breathing equipment or components
Oxygen Cleaning Solutions Use as Trained
Promoclean TP1113 or TP108 (diluted
with warm water to a maximum of 5%)
Nitrox/Oxygen Cleaning Inventec Performance Chemicals SA
20, Rue de Bourgogne
BP 211
69802 Saint-Priest Cedex
BIOX O2 Liquid Nitrox/Oxygen Cleaning The Granary, Yeo Lane, North Tawton,
Devon, UK. EX20 2DD
www.bioxint.com
Disinfectant solutions
Liquid dishwashing detergent
(diluted with warm water) *Soapy water
is dened as ‘household’ grade liquid
dishwashing detergent diluted in warm
water
General low risk disinfecting ‘Household grade’
Chemgene HLD4L breathing
apparatus surface disinfectant
solution. Follow the manufacturers
dilution recommendations
All round non-corrosive disinfecting
for all plastic and metallic parts.
Shared training and rental
equipment
http://www.medi-mark.co.uk
STERANIOS 2% Ready to
use. (Toxic, follow manufacturer’s
instructions for use)
All round disinfecting for all plastic
and metallic parts. Shared training
and rental equipment
Aqua Lung Ref: 382062
CAUTION: Disinfection of products for multi-use applications such as Training and rental equipment
must be carefully considered. Do not use bleach based disinfectants or disinfectants known to be
corrosive, such as Milton, as these can prematurely age or corrode the equipment being used.
NOTE: Always follow the guidelines of use, cleaning procedures and safety data sheets published by the
cleaning and disinfectant solution manufactures. Methods, temperatures, dilution ratios and times can vary.
These cleaning solutions and disinfectants have been developed and are intended for use with compressed
oxygen diving and life support systems and are accompanied with detailed information.
Always follow your local regulations and cleaning solution guide lines regarding disposal.
Table 3 - Recommended Lubricants, Cleaning & Disinfectant Solutions Continued

18
XL4 2nd Stage Maintenance Manual
Cleaning & Lubrication Procedure
WARNING: Always wear the appropriate Personal Protective Equipment such as medical
gloves and safety glasses.
General Cleaning of Brass and Stainless-Steel Parts
1. Pre-clean by soaking in warm soapy water*. If required soak in NETALU diluted to 25%, or other diluted general
cleaning solutions as recommended and shown in the Recommended Cleaning Solutions table. Use a nylon
bristle toothbrush as required.
3. Remove parts from the ultrasonic cleaner, rinse and soak parts for ten minutes with fresh water, agitate lightly.
If tap water is extremely ‘hard’ then rinse in distilled water to prevent any mineral residue. Dry with ltered low
pressure (1.75 bar/25psi) air or leave to dry naturally. Check that their condition is now suitable for re-use.
2. Thoroughly clean the parts in a hot ultrasonic bath lled with a mixture of soapy water*. If some deposits remain
then ll the bath with diluted white vinegar (acetic acid), max 50%, and repeat.
CAUTION: Do not place plastic, rubber, silicone or anodised aluminium parts in contact with Vinegar.
Anodised aluminium parts are to be soaked and cleaned with warm soapy water*. Use only a soft nylon
toothbrush to scrub away any deposits. Rinse in fresh water and dry with ltered low pressure (1.75 bar/25psi)
air or leave to dry naturally. Check that their condition is now suitable for re-use. If required prior to cleaning with
warm soapy water and rinsing, pre-soak in NETALU diluted to 25%.
CAUTION: Do not place plastic and rubber parts in acid solutions. Doing so may alter the physical
properties of the component and cause degradation and premature breakdown.
*Soapy water is dened as ‘household’ grade liquid dishwashing detergent diluted in warm water.
General Cleaning of Plastic, Composite, Rubber and Anodised Aluminium Parts
Parts made from plastic or soft materials such as rubber, for example, box bottoms, cases, covers etc., are to be
soaked and cleaned with warm soapy water*. Use only a soft nylon toothbrush to scrub away any deposits. Rinse
in fresh water and dry with ltered low pressure (1.75 bar/25psi) air or leave to dry naturally. Check that their
condition is now suitable for re-use.
If required the use of an ultrasonic bath can be used, but only with warm soapy water.

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XL4 2nd Stage Maintenance Manual
Cleaning parts for Nitrox and Oxygen use
WARNING: Please check the regulations regarding Oxygen/Nitrox in your particular
country, as this may differ from Aqua Lungs standard policy. Always follow the training
received for Oxygen Cleaning.
WARNING: Always use genuine authorised service kit components and lubricants which
are recommended and oxygen/nitrox compatible. New service kit components are also
required to follow these cleaning guidelines.
WARNING: During testing and use of the regulator following oxygen cleaning it is
essential that only Oxygen Compatible Air in accordance with EN12021:2014 (or later) is
used. Standard compressed Breathing Air in accordance with EN12021 or often referred
to as Grade E in the United Sates, does not meet this criterion and could contaminate the
regulator.
Although regulator second stage components are not exposed to high pressure oxygen/nitrox, Aqua Lung and
Apeks recommends that the same cleaning procedure is followed for the complete regulator. This prevents the
cross contamination and guarantees the cleanliness of the entire regulator.
Hoses shall be cleaned for Oxygen use in accordance with the Aqua Lung document ‘Hose inspection and
Cleaning Procedure’
1. Complete the General Cleaning sections on all parts as listed previously.
2. Ultrasonic cleaning at 50oC [122oF] in Promoclean TP1113 or TP108 diluted at 5%, or other Oxygen Cleaning
Solutions shown in the recommended cleaning solutions list, for at least 6 minutes. **
3. Rinse in warm demineralised water. Soak for 10 minutes.
4. Dry in open air in a controlled clean and dust free atmosphere. Place the parts on a white cloth, allow to dry and
check after drying that the cloth shows no grease deposits and that the condition of the parts are appropriate for
reuse with Nitrox/Oxygen.
**Note: Always follow the guidelines of use, cleaning procedures and safety data sheets published by the cleaning and
disinfectant solution manufactures. Methods, temperatures, dilution ratios and times can vary. These cleaning solutions and
disinfectants have been developed and are intended for use with compressed oxygen diving and life support systems and are
accompanied with detailed information.
General Cleaning of Hoses.
Hoses shall be cleaned and maintained. Refer to Aqua Lung document ‘Hose inspection and Cleaning Procedure’
CAUTION: Do not place complete hose length in contact with acid solutions. Doing so may alter the
physical properties of the component and cause degradation and premature breakdown.

20
XL4 2nd Stage Maintenance Manual
Wiping
To wipe parts, use a white lter paper, a pure cotton cloth or any other material that is lint free and does not
produce uff.
Inspection
Visually check under a white light (daylight or articial light).
The parts are to be completely free of any traces of:
1. Organic materials (oil, grease, paint, rust….)
2. Cleaning agents
3. Dust
4. Humidity
When handling and lubricating O-rings, wear powderless latex gloves. Keeping internal parts free from skin oils
and other contaminates is always important especially when the regulator is being prepared for Nitrox and Oxygen
use. All Seals shall be lubricated with an oxygen compatible grease as recommended and shown in the lubricants
table, such as Christo-Lube MCG111. Dress the O-rings with a very light lm of grease and remove any excess by
running the O-ring between thumb and forenger. Do not apply excessive amounts of grease, as this will attract
particulate matter that may cause damage to the O-ring.
Lubrication and Dressing for General and Oxygen use
Disinfecting parts and products. (Multi Use Rental and Training Equipment)
CAUTION: Disinfection of products for multi-use applications such as Training and rental equipment
must be carefully considered. Do not use bleach based disinfectants or disinfectants known to be
corrosive, such as Milton, as these can prematurely age or corrode the equipment being used. Only
use the recommended disinfectant solutions. Further information on recommended diluted solutions,
when to use and risks are explained in document DOC-0053-O-02 Cleaning and Disinfectant Protocol
for high level training use of Underwater Breathing Apparatus.