Apeks GX300 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. AP2548
Issue 4
28/08/2015
AQUA LUNG G3000SS DIVING HELMET
FOR THE
GX300 REGULATOR

2
GX300 Regulator 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:
1 1446 AP2553 Diaphragm part number 30.
Bought in diaphragm changed to Apeks. 12/03/15 2 CT DL
2Page 13 Functional Bench Test of Helmet
and Regulator. 20/03/15 3 CT DL
3Page 11 action 3 text amendment to
remove 1/2 turn adjustment. 28/08/15 4 CT DL

3
GX300 Regulator Maintenance Manual
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 repairs 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. Before beginning any disassembly, it is important to rst
perform the initial inspection procedure. Refer to Table
1 : Troubleshooting Guide page 10, to determine the
possible cause of any symptoms which may be present.
4. As each unit is disassembled, reusable components
should be segregated and not allowed to intermix with
non-reusable parts or parts from other units. Delicate
parts, including valve spindles and valve seats which
contain critical sealing surfaces, must be protected and
isolated from other parts to prevent damage during the
cleaning procedure.
5. Use only genuine Apeks parts provided in the service kit.
6. 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.
7. When reassembling, it is important to follow every torque
specication prescribed in this manual, using a calibrated
Newton Meter (Nm) or Inch Pound (in.lb) torque wrench.
Most parts are made of either marine brass or plastic,
and can be permanently damaged by undue stress.
SCHEDULEDSERVICE
The same service schedule as outlined in the Gorski
technical manual should be followed but using the regulator
service kit and tools described in this manual. The G3000SS
diving helmet is subject to annual service regardless
of usage. With heavy use in contaminated water it is
recommended to service the regulator more regularly. In
some contaminated water it may be preferable to replace
the regulator seals after every use and this should be
determined via risk assessment.
The G3000SS helmet has been CE certied by
Germanischer Lloyd SE, Brooktorkai 18 . 20457 Hamburg,
Germany Notied Body number 0098 and has been found to
be in accordance with the requirements of Council Directive
89/686/EEC. When examined the product satised the
requirements of the manufacturer’s technical specications
(based upon BS EN 153333 requirements), which has been
previously assessed and deemed to meet the basic health
and safety requirements (Annex II) ot the directive.
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 in writing from Apeks Marine Equipment Ltd.
©2013 Apeks Marine Equipment Ltd.
G3000SS DIVING HELMET
(APEKS GX300 REGULATOR)
Maintenance Manual(19/03/2015 Issue 3)
This manual provides factory prescribed procedures for the
correct installation, adjustment and maintenance of the Apeks
GX300 regulator tted to the G3000SS diving helmet. This
is intended as a supplement to the Gorski G2000SS helmet
technical maintenance manual.
The G3000SS diving helmet is a G2000SS helmet but with the
following important revisions:
- Apeks GX300 2nd stage regulator
- Double exhaust and double water dump.
- Ergonomic free ow knob
- 4-wire communications (Marsh Marine or Hi-Use version)
This manual should be read in conjunction with the G2000SS
manual. Instructions for upgrading a G2000SS to a G3000SS
are included in this manual.
All the checklists and set-up procedures described in the
G2000SS technical manual need to be followed.The
procedures outlined within this manual are to be performed only
by personnel who have received factory authorised training. If
you do not completely understand all of the procedures outlined
in this manual, contact Apeks or Aqualung to speak directly with
a Technical Advisor before proceeding any further.
As with the G2000SS helmet the diver is recommended to carry
an emergency gas supply so that in the event of an interupted
umbilical supply the diver has enough reserve gas to return to
a place of safety. With the G3000SS diving helmet there are
various options for the emergency gas supply or bail out. These
options are laid out later in this manual.
COPYRIGHT NOTICE
INTRODUCTION
WARNINGS, CAUTIONS & NOTES
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.
GENERAL GUIDELINES

4
GX300 Regulator Maintenance Manual
1. Unscrew valve cover
(11) counter clock
wise. Leave the purge
button in place unless
defective.
2. Remove spring
carrier (9), diaphragm
spring (8) and valve
diaphragm assembly.
3. Using a 3/4” spanner
(AT33) unscrew valve
lock nut (1).
4. Remove spindle assembly by pushing exposed thread
from valve lock nut removal. Use the lever (25) to guide
out the spindle if required.
5. Unscrew the 4 mouthpiece screws (5) using the 5/64”
allen key.
6. Remove O ring (3) using
O ring removal tool
AT79.
7. Unscrew side valve case (2) from side valve diaphragm
housing (7) counter clock wise by hand whilst gently
pulling apart.
8. Remove O ring (3)
from valve case (2)
using O ring removal
tool AT79.
9. Remove O ring (6)
from valve diaphragm
housing (7) using O
ring removal tool AT79
Disassembly Procedures for the GX300
Regulator Case
Disassembly of the GX300 Regulator Case
is Now Complete

5
GX300 Regulator Maintenance Manual
11. Remove lever washer (26) and lever (25) by sliding
out of valve spindle slots.
10. Remove Nylock nut (27) using 7mm nut driver or
spanner and put to one side.
17. Remove the O ring
(12) from the valve
seat (13) using the
O ring removal tool
AT79.
Disassembly Procedures for the Valve
Spindle Assembly
12. Unscrew the spindle
adjuster (24) counter
clockwise by hand.
18. Remove the O ring
(14) from the valve
spindle (15) using
O ring removal tool
AT79.
16. Guide the seat tool (109437) into the shaft of the side
valve spindle (15) plastic end rst and push the valve
seat (13) until it protrudes from the other end.
14. Using the protruding arms of the spindle locking washer
(22) pull the whole side valve shuttle assembly from the
side valve spindle (15).
13. Ret Nyloc nut (27) by hand, screw down until male
thread of the valve shuttle (17) reaches nylon in the
nut.
15. Using slotted valve
adjustment tool
(AT51/L) unscrew the
valve seat (13) until the
thread disengages.
Caution: Take care when removing parts 25 and 26
as they may fall out easily. The lever washer (26) is
not replaced during service and must be retained.
Caution: Take care when handling the valve seat (13)
that no damage is caused to the actual sealing edge.

6
GX300 Regulator Maintenance Manual
23. Remove O ring (19)
from valve shuttle
(17).
25. Remove silicone seat
(16) from valve shuttle
(17).
24. Remove O ring (18)
from valve shuttle (17).
22. Remove spring (20)
from valve shuttle
(17).
20. Remove O ring (12)
from the spindle bush
(23).
21. Slide the valve sleeve (21) from the side valve shuttle
(17) and remove O ring (12)
19. Unscrew nyloc nut (27) and dispose of, then slide the
spindle bush (23) and spindle locking washer (22) free
from the side valve shuttle (17).
Disassembly of the Valve Spindle
Assembly is Now Complete

7
GX300 Regulator Maintenance Manual
5. Push on the
underside of the
diaphragm ring
(32) to reveal the
diaphragm (30) and
retaining ring (35).
Remove retaining
ring (35) gently to
avoid damage to the
diaphragm (30) and
teeth of the ring.
7. Lift the edge of the
diaphragm (30) and
pull away from the
diaphragm carrier
(29). Ease out the
diaphragm (30) from
the groove which it
was seated into all
the way round to
release.
6. Push on the underside of the diaphragm ring (32)
to reveal the diaphragm (30). Peel the diaphragm
(30) at one edge to reveal the groove which it was
seated in and work free all the way around until the
diaphragm ring (32) is free.
2. Gently lift the
exhalation diaphragm
(33) at the edge and
pull away from the
diaphragm ring (32).
4. Remove diaphragm
pad (31) by holding
the assembly rmly
and pulling the pad
outwards.
3. Remove O ring (28)
from diaphragm
carrier (29) groove.
1. Remove sealing disc
(34) by gently lifting
it by the edges and
sliding it out of the
diaphragm ring (32).
Caution: Check the diaphragm (30) and exhalation
diaphragm (33) for holes or imperfections.
Disassembly Procedures for the Valve
Diaphragm
Disassembly of the Valve Diaphragm is
Now Complete

8
GX300 Regulator Maintenance Manual
1. Place the diaphragm
carrier (29) at on the
bench with the internal
diaphragm groove
facing upwards.
2. Press the diaphragm (30) into the carrier groove
with the text on the diaphragm facing upwards.
3. Work the diaphragm
(30) around pressing
it rmly into the carrier
groove evenly so the
face with text sit’s ush.
Check for creases.
4. With the projecting guide pin of the diaphragm ring
(32) facing upwards fit inner edge of diaphragm
(30) into diaphragm ring (32) pressing into groove.
Press into place all the way around evenly.
5. Carefully push on retaining ring (35) to diaphragm
(30). Ensure the eight teeth on the retaining ring
(35) are facing towards the diaphragm (30). They
must also fit between the four stop lugs of the
diaphragm (30) but not go past or over them.
6. Fit the exhalation diaphragm (33) to the centre pin on the
diaphragm ring (32). Press well down into the valve seat so
that the sealing edge is pre-loaded towards the diaphragm
ring (32) with the projecting part facing outwards.
7. Push diaphragm pad
(31) into the groove on
diaphragm ring (32).
Press rmly until the
pad is seated flush
or clicks into place.
8. Place the sealing disc
spigot (34) into the hole
on the projecting guide
pin of the diaphragm
ring (32) and press
lightly into place.
9. Fit the lightly
lubricated O-ring (28)
into the diaphragm
carrier (29) groove.
Assembly Procedures for the Valve
Diaphragm Assembly
Caution: Check air escape holes are clear on the
underside of the diaphragm carrier (29), hold it up
to the light to check. If the holes are not clear the
diaphragm (30) will not seat. Use a pin to remove any
debris if required.
Caution: When tting diaphragm (30) make sure not
to disengage from carrier (29). Assembly of the Valve Diaphragm is
Now Complete

9
GX300 Regulator Maintenance Manual
NOTE: Lubricate valve shuttle (17) shaft only. Do not
lubricate threads or silicone valve seat end.
1. Push O ring (14) over
threads of spindle (15)
into O ring groove.
3. Push valve seat (13) into the valve spindle (15) then
screw all the way in with the slotted valve seat adjuster
(AT51/L).
Assembly Procedures for the GX300
Inlet Valve
4. Fit O ring (19) into the
rst groove on valve
shuttle (17) using seal
expander (AT67).
5. Fit O ring (18) into groove on valve shuttle (17) into O
ring bottom groove.
6. Place the silicone valve seat (16) on a clean at surface
face down. Press the valve shuttle (17) onto the seal
until its fully located into place.
7. Fit O ring (12) into groove on side valve sleeve (21).
9. Slide side valve sleeve (21) over valve shuttle (17). Pass
valve shuttle (17) through large bore end of the valve
sleeve (21). Locate over O rings until it meets the spring
making sure it will compress the spring.
10. Slide valve shuttle
assembly into spindle
(15) seat end rst.
2. Fit O ring (12) onto
valve seat (13).
8. Slide spring (20) over
valve shuttle (17).
Caution: Do not overtighten valve seat (13) into side
valve spindle (15).
Caution: Take care when handling the silicone valve
seat (16), not to cause damage to the face side.

10
GX300 Regulator Maintenance Manual
11. Fit spindle locking
washer (22) onto
exposed thread on
valve shuttle. Locate
into long spindle slots
with ats on washer.
The side valve shuttle
(17) can be rotated to
aid lining up.
12. Screw spindle adjuster
(24) over exposed
thread on valve shuttle
(17) and onto spindle
all the way down.
Then back off (turn
counter clockwise)1
full turn and 1/6 of a
turn (7 holes).
13. Fit O ring (12) onto
spindle bush (23).
14. Place spindle bush over exposed thread on valve shuttle
and push into the spindle as far as it will go using seal
expander (AT82).
17. Tighten nyloc nut
(27) with 7mm nut
driver or spanner onto
spindle until there
are two complete
threads visible past
the end of the nyloc
nut. There should be
roughly 5mm of free
movement at the end
of the lever. This is
a preliminary setting
only
18. Fit lightly lubricated
O-ring (3) onto valve
case (2), locate into
groove.
19. Fit lightly lubricated
O ring (6) onto valve
diaphragm housing
(7), locate into groove.
15. Place lever (25) into spindle slots on spindle facing
spindle hole.
16. Fit lever washer
(26) over threads
on spindle and rest
against the lever.
20. Screw valve case (2) into diaphragm housing (7) all the way
in until the thread disengages. The valve case should rotate
freely. Align mouthpiece slot up with diaphragm housing.
Correct Incorrect
Assembly of the GX300 Inlet Valve is Now
Complete
NOTE: The lever will only t one way easily and should
not be forced into the slots. It should be positioned with
the spoon back facing upwards.
Assembly Procedures for the GX300
Regulator Case
NOTE: The spindle adjuster sets the cracking effort.
The ‘7 hole’ setting is the optimum setting for normal
diving operations. For further adjustment see page 11.

11
GX300 Regulator Maintenance Manual
23. Fit spindle assembly (A) into valve case locating into
slot at bottom face of case. Position lever as shown.
Press the lever on to the housing to ensure free
movement.
Assembly of the GX300 Regulator Case
is Now Complete
24. Pull thread of spindle assembly to reveal fully. Screw
valve lock nut (1) over spindle, ange side out using
3/4” spanner (AT33) and tighten to a torque value of
5Nm (44 in.lb).
Regulator Adjustment is Now Required
22. Place mouthpiece (4) onto valve case and fasten with
the 4 allen key screws (5) using 5/64” allen key to 0.5
Nm (4 in.lb).
Caution: Check O ring is still engaged whilst tightening
screws. Partially take screws down, then tighten until
the mouthpiece bottoms out. Any further tightening
may damage the case.
21. Fit O ring (3) into groove on mouthpiece (4). Regulator Adjustment and Leak Test
1. Connect to a regulated
air source between
9.2 bar (133 psi) and
9.8 bar (142 psi).
2. Partially actuate the lever to check the regulator
vents. Then submerge in water and check for leaks.
3. Remove from water. Turn
the locknut clockwise
until air starts to vent. As
soon as air starts to vent
loosen (i.e. turn counter
clockwise) the locknut
until the leak completely
stops, then continue to
loosen a further 1/4 turn.
There should be some
free play in the lever.
4. Once set the full
regulator is submerged
in water and checked
for leaks.
Regulator Adjustment is Now Complete
See Page 12 for Optional Magnehelic
Setting
Exhaust Assembly Required See Page 12
NOTE: If air starts to vent when supply is started, turn
locknut counter clockwise until it stops.
NOTE: Ensure the mouthpiece is facing upwards to
allow trapped air to release.
NOTE: If the air continues to vent, disassemble and
check parts.
5. Remove from water.
Depress the purge
button fully to expel any
water and to ensure
that an adequate
volume of air needed
to clear the second
stage flows through
the mouthpiece.

12
GX300 Regulator Maintenance Manual
1. With the cover installed
place the regulator
mouthpiece onto the
Magnehelic test bench
and read the gure on
the gauge.This should
read between 2.0” and
2.5” H2O. Repeat
again to ensure a
constant reading.
2. To adjust the regulator
use a small allen key
to engage the spindle
adjuster holes and
turn. To reduce the
cracking effort turn
counter clockwise. To
increase the cracking
effort turn clockwise.
Adjust one hole span
at a time before
reassembling the cap
and retesting from
step 4 from page 11.
Cracking Effort Fine Adjustment Using
Optional Magnehelic Gauge
NOTE: If the reading is outside the given range the cover
and exhaust valve must be removed and the regulator
adjusted.
NOTE: The regulator can be adjusted whilst tted into
the helmet (i.e. eld adjustment) and without using a
Magnehelic gauge. It must be recognised that in order
to achieve the most accurate setting the regulator
should always be removed from the helmet and set on
a Magnehelic gauge.
1. Fit valve diaphragm assembly into diaphragm housing
(7).
2. Fit diaphragm spring (8) to spring carrier (9) and t
assembly into valve cover (11).
3. Screw cover onto diaphragm housing until hand tight .
NOTE: Make sure O-ring (28) on diaphragm assembly
remains in place.
Assembly of the Exhaust Valve is
Now Complete
Assembly Procedure of the
Exhaust Valve
Return to Page 11 to Complete Leak
Testing Step 4
4. Press the purge
button to ensure all
parts are operational
and have free
movement.
NOTE: For assembly instructions of the exhaust valve
internal components see page 8.
2. The spindle adjuster may be adjusted as detailed above
to take account of local diving conditions. For example,
when using a LP compressor supply it is acceptable to
reduce the cracking effort by turning the spindle adjuster
counter clockwise up to 14 holes. After adjustment the
regulator must be reassembled and retested from point
4 from page 10.
1. The normal 7 hole setting of the spindle adjuster (see page
10) is the optimum setting for normal diving operations.
At this setting the regulator will function correctly within
a wide range of regulated supply pressures (see GX300
Regulated Supply Pressure Guidelines on page 15).
Cracking Effort – User Adjustment
Guidelines

13
GX300 Regulator Maintenance Manual
Final Installation of the GX300 Regulator is
Now Complete
2. Push spindle into free ow device until it locates into
place.
3. Place oral nasal mask
over mouthpiece.
4. Screw down regula-
tor cap (11) until it is
hand tight. Ensure
the grooves on the
cap line up with the
screw holes.
1. Fit complete regulator
into helmet. Position
mouthpiece to bottom
of helmet, then rotate
into place for entry.
5. Fit the 3 new cap head screws (10), tighten each screw
using a 5/32” allen key to 5Nm (44 in.lb).
Final Assembly of the GX300 Regulator
into the Helmet
Caution: Do not overtighten as this may damage the cover
or valve case!
Functional Bench Test of Helmet and
Regulator (“Neck Dam Pull Test”)
8. Slowly pull the
bunched end of the
neck seal out to
full extension, then
push back fully into
the helmet. Repeat
this 3 or 4 times. The
regulator should be
heard to open and
close (i.e. inhale and
exhale). This pull &
push action simulates
a diver breathing
in the helmet. A
properly serviced and
adjusted regulator
should deliver air
upon deep inhalation
without excessive
inhalation effort,
freeow, or “uttering”
of the second-stage
regulator.
7. Take hold of the open
end of the neckseal
and “bunch” tightly to
ensure that the open
end is “sealed”.
6. Fit the regulator into the helmet and t the neck dam
assembly. Connect the helmet to a regulated air source
between 9.2 bar (133 psi) and 9.8 bar (142 psi).

14
GX300 Regulator Maintenance Manual
1. Remove the 5 dome
head screws using a
Phillips#3 screwdriver.
2. Remove cover plate.
3. Disengage oral nasal
mask.
8. Place oral nasal mask
over mouthpiece.
6. Fit complete regulator
into helmet. Position
mouthpiece to bottom
of helmet, then rotate
into place for entry.
NOTE: When retro tting the new GX300 regulator to an existing G2000SS helmet it will then be known as the Aqualung
G3000SS helmet. A double exhaust kit (water dump), PN 400111, should be tted to the helmet at the same time.
4. Remove Poseidon
regulator using a at
blade screwdriver.
Use screwdriver as
a lever against nose
clearing device to
push the regulator out.
5. Slide out regulator
rotating downward to
ease removal.
7. Push regulator spindle onto free ow valve until it locates
rmly into place.
9. Screw down regulator
cap (11) until it is
hand tight. Ensure the
grooves on the cap
line up with the screw
holes.
10. Fit the 3 new cap head screws (10), tighten each screw
using a 5/32” allen key to 5Nm (44 in.lb).
Fitting the GX300 Regulator
Upgrading the G2000SS Diving Helmet with the GX300 Regulator
NOTE: Keep all screws and cover plate (needed to t
the optional free ow blanking plug system).
Caution: Do not overtighten as this may damage the
cover or valve case!
Removing the Old Regulator

15
GX300 Regulator Maintenance Manual
GX300 Regulated Supply Pressure Guidelines
(MSW) (FSW)
MINIMUM MAXIMUM MINIMUM MAXIMUM
00-20 00-66 8.9 10.9 129.0 158.0
21-30 69-98 11.0 12.4 160.0 180.0
31-40 102-131 13.3 15.4 193.0 223.0
41-50 135-164 17.5 20.5 254.0 297.0
51-60 (not recommended
when using normal air)
167-197 21.5 22.5 312.0 326.0
Pressures based on providing sufficient breathing performance at a RMV of 62.5 lpm
RECOMMENDED SUPPLY PRESSURE RANGE
(BAR) (PSIG)
DEPTH
Emergency Gas Supply Options
The G3000SS is designed to be used with the following congurations of Emergency Gas
Supply (EGS) or bail out system:
Option 1:
a.AquaLung G3000SS Diving Helmet
b.Main surface MP gas supply, using surface gas control panel and standard diver’s umbilical, connected directly into one
port of the G3000SS Helmet
c. Apeks Quick Disconnect Hose -AP0205/Y, into the second port of the G3000SS Helmet
d.Apeks Switch Block - AP0281/G, connected to the other end of the QD hose via the bail out port
e.One of Apeks First Stage Regulators:
i. DS4 First Stage Regulator - AP0528
ii. DST First Stage Regulator - AP0361-1 & AP0361F-1
iii. FST First Stage Regulator - AP0362-1 & AP0362F-1
iv. FSR First Stage Regulator - AP0364-1 & AP0364F-1
f. Apeks Pressure Gauge - AP0633, on the rst stage
g.Apeks Pressure Relief Valve - AP0849, on the rst stage
h.AquaLung H3 Harness - 400800, to mount the Switch Block (chest strap or waist strap position) and the bail out cylinder
i. IDEST certied bail out cylinder (with sufcient volume for emergency)
j. Apeks 36” Regulator Hose - AP0206, connecting the Switch Block and rst stage regulator
k. Apeks CE certied cylinder valve with the rst stage connected
High Pressure (HP) Gas Supply Systems. The GX300 Regulated Supply Pressure Guidelines
apply to conventional surface supply systems providing a regulated gas supply to the diver
through a Medium Pressure (MP) umbilical. If a HP gas supply system is used these guidelines
do not apply. The HP gas supply system will automatically adjust the diver’s gas supply pressure
with changes in depth. Always refer to the manufacturer’s instructions for the system being used.

16
GX300 Regulator Maintenance Manual
Option 2:
a.AquaLung G3000SS Diving Helmet
b.Tatum SLS high pressure (HP) gas supply system with high pressure umbilical connected to the Tatum pressure reducer
(mounted on diver)
c. Apeks Quick Disconnect Hose -AP0205/Y, into one port of the G3000SS Helmet from the Tatum pressure reducer
d.One of Apeks First Stage Regulators:
i. DS4 First Stage Regulator - AP0528
ii. DST First Stage Regulator - AP0361-1 & AP0361F-1
iii. FST First Stage Regulator - AP0362-1 & AP0362F-1
iv. FSR First Stage Regulator - AP0364-1 & AP0364F-1
e.Apeks Pressure Gauge - AP0633, on the rst stage
f. Apeks Pressure Relief Valve - AP0849, on the rst stage
g.AquaLung H3 Harness - 400800, to mount the pressure reducer and the bail out cylinder
h.IDEST (or equivalent) certied bail out cylinder (with sufcient volume for emergency)
i. Apeks 36” Regulator Hose - AP0206, connecting the Tatum pressure reducer and rst stage regulator
j. Apeks CE certied cylinder valve with the rst stage connected
Option 3:
a. AquaLung G3000SS Diving Helmet
b. Main surface MP gas supply, using surface gas control panel and standard diver’s umbilical, connected directly into
one port of the G3000SS Helmet
c. Apeks Quick Disconnect Hose -AP0205/Y, from the rst stage regulator to the second port of the G3000SS Helmet
d. One of Apeks First Stage Regulators:
i. DS4 First Stage Regulator - AP0528
ii. DST First Stage Regulator - AP0361-1 & AP0361F-1
iii. FST First Stage Regulator -AP0362-1 & AP0362F-1
iv. FSR First Stage Regulator - AP0364-1 & AP0364F-1
e. Apeks Pressure Gauge - AP0633, on the rst stage
f. Apeks Pressure Relief Valve - AP0849, on the rst stage
g. AquaLung H3 Harness - 400800, to mount the bail out cylinder
h. IDEST certied bail out cylinder (with sufcient volume for dive undertaken)
i. Apeks CE certied cylinder valve with the rst stage connected
NOTE: In option 3, prior to diving the cylinder valve is to be opened fully and then closed: this leaves the bailout hose
pressurised during the dive.
WARNING: In option 3, when not using a switch block the cylinder should be mounted with the cylinder valve at the bottom.
The valve should be left switched off to prevent accidental loss of the back up air. The diver should check that they can access
the cylinder valve in an emergency to switch to the bail out supply.
WARNING: The diver should ensure the two check valves are in position on the G3000SS helmet and that they are fully
operational. In an emergency situation the lack of operational check valves could lead to loss of pressure and even a fatality.

17
GX300 Regulator Maintenance Manual
Table 1 - Troubleshooting Guide
SYMPTOM POSSIBLE CAUSE TREATMENT
Leakage from
regulator
exhaust ports.
1. Excessively high supply pressure. 1. Ensure supply pressure is below the
maximum stated within the pressure
guidelines.
2. Supply pressure is above the standard
setting.
2. Wind in the spindle adjuster until leaking
stops (Note: This will affect breathing
performance).
3. Silicone seat (16) damaged or not
seating correctly.
3. Replace seat and ensure metal valve is fully
screwed in and undamaged.
4. Lever (25) set too high. 4. Adjust lever.
5. Lever (25) bent. 5. Replace lever.
6. Valve spring (20) damaged or incorrect. 6. Replace spring.
7. Shuttle valve O rings (18,19) damaged. 7. Replace O rings.
8. Sleeve (21) bore damaged. 8. Replace sleeve.
9. Valve seat O ring (12) damaged. 9. Replace O ring.
10. Diaphragm spring (8) out of position or
incorrect.
10. Remove cap and check spring.
11. Exhaust valve (Diaphragm Assembly -
item 33) damaged or snagged.
11. Check exhaust valve around its sealing
edge and replace if required.
12. Sealing disc (Diaphragm Assembly -
item 34) not in contact with rubber seating
edge.
12. Check for free movement of sealing disc
and check sealing surface.
13. Dirt or ice build up around exhausts. 13. Check and clean.
14. Diaphragm O ring (Diaphragm
Assembly - item 28) damaged or out of
position.
14. Check and replace O ring.
15. Diaphragm (Diaphragm Assembly item
30) disengaged or out of position.
15. Inspect diaphragm, make sure it’s secure
in the groove and replace if torn or looking
perished.

18
GX300 Regulator Maintenance Manual
SYMPTON POSSIBLE CAUSE TREATMENT
Excessive
work of
breathing.
1. Low supply pressure. 1. Check equipment upstream.
2. Lever (25) set too low. 2. Adjust lever.
3. Interruption in supply to the
regulator.
3. Check for leaks. Check the supply hoses are
clear and not kinked.
4. Lever (27) bent and catching on valve
spindle.
4. Check lever slots are clear and replace lever
if bent.
5. Spindle (15) orientated incorrectly. 5. Check position against diaphragm in manual.
6. Diaphragm ( Diaphragm Assembly
- item 29) or sealing disc (34) failing to
create a seal.
6. Inspect parts then remove regulator for
vacuum test.
7. Oral nasal mask failing to create a good
seal.
7. Check mask condition, correct seating of
oral nasal valve, microphone and also check
the mask is properly engaged on the regulator
mouthpiece.
8. Regulator failing to make a good seal. 8. Check all O rings in regulator case (3 & 6)
and check alignment with free ow device.
9. Check that the adjuster (24) is in its
default setting.
9. Check rst with setting tool and then with a
pressure gauge.
10. Seizing of the spindle parts. 10. Manually check for dirt ingress and free
movement of the shuttle valve inside the
spindle.
Water
entering
regulator
1. Diaphragm (30) damaged or
disengaged.
1. Inspect diaphragm, make sure its secure
in the groove and replace if torn or looks
perished.
2. Diaphragm (30) improperly seated. 2. Check diaphragm for any ripples, remove
and ret keeping it level all the way around
and ush with the carrier.
3. Exhaust valve (33) damaged or
snagged.
3. Inspect exhaust valve and replace.
4. Housing (7) cracked. 4. Disassemble and replace the housing.
5. Regulator cover (11) not fully screwed
down.
5. Fully hand tighten cover.
6. Diaphragm O ring (28) damaged. 6. Replace O ring.
7. Housing O ring (6) damaged. 7. Replace O ring.
8. Sealing disc (34) not in contact with
rubber seating edge.
8. Check for free movement of sealing disc
and check sealing surface.
9. Dirt or ice build up around exhausts. 9. Check and clean.
10. Diaphragm spring (8) out of position
or incorrect.
10. Remove cap and check spring.

19
GX300 Regulator Maintenance Manual
PART NO. DESCRIPTION APPLICATION
AT33 3/4” Spanner Side Valve Lock Nut (1)
AT51/L Slotted Valve adjustment Tool Valve Seat (13)
AT88 Seal Expander O Ring (18+19)
AT79 O Ring Tool O Ring Removal
109437 Seat Tool Valve Seat Removal (13)
N/A 7mm Nut Driver Nyloc Nut (27)
N/A 5/32” Allen key Cap Head Screws (10)
N/A 5/64 Allen key Mouthpiece Screws (5)
N/A Phillips #3 Screwdriver Cap Head screws (exhaust valve cover)
N/A Flat Head Screwdriver Regulator Removal from Helmet
Table 2 - Recommended Tool List
5/32”
ALLEN
KEY
AT33
5/64”
ALLEN
KEY
AT51/L
AT79
AT88
FLAT HEAD
SCREWDRIVER
109437
PHILIPS
SCREWDRIVER
NUT DRIVER

20
GX300 Regulator Maintenance Manual
Cleaning and Lubrication Procedure
Lubrication and Dressing
All O rings should be lubricated with Christo-Lube MCG-111 or PerFluoroLube 20/1. Dress the O rings with a
very light lm of grease, and remove any visible excess by running the O ring between thumb and forenger.
Avoid applying excessive amounts of lubricant as this will attract particulate matter that may cause damage
to the O ring.
Caution: Do not place plastic and rubber parts in acid solutions. Doing so may alter the
physical properties of the component, causing it to prematurely degrade and/or break.
Cleaning Plastic & Rubber Parts
Parts made of plastic or rubber may be soaked and cleaned in a solution of warm water mixed with
mild dish soap. Use only a soft nylon toothbrush to scrub away any deposits. Rinse in fresh water and
thoroughly blow dry, using low pressure ltered air.
Cleaning Brass and Stainless Steel Parts
1. If required, pre-clean in warm, soapy water* using a nylon bristle tooth brush.
2. Thoroughly clean parts in an ultrasonic cleaner lled with a solution of household white distilled vinegar
(Acetic Acid) mixed with fresh water (max 50% vinegar). Clean ultrasonically for 5 minutes (max 10
minutes). DO NOT place plastic, rubber, silicone or anodized aluminium parts in vinegar.
3. Remove parts from the ultrasonic cleaner and rinse with fresh water. If tap water is extremely “hard,”
place the parts in a bath of distilled water to prevent any mineral residue. Agitate lightly, and allow to soak
for 5-10 minutes. Remove and blow dry with low pressure (25 PSI/1.7 Bar) ltered air. Inspect closely to
ensure proper cleaning and like-new condition.
*Soapy water is dened as “household” grade liquid dishwashing detergent diluted in warm water.