Aqua Lung Legend First Stage User manual

Authorized Technician
Technical MainTenance Manual
leGenD FiRST STaGe

2
CONTENTS
Copyright Notice...................................................................................................................................3
General Guidelines...............................................................................................................................3
General Conventions............................................................................................................................3
DISASSEMBLY PROCEDURE ............................................................................................................4
REASSEMBLY PROCEDURE .............................................................................................................6
ADJUSTING THE FIRST STAGE.........................................................................................................9
FINAL ASSEMBLY ...............................................................................................................................9
FINAL TESTING.................................................................................................................................10
Immersion Test .............................................................................................................................10
Subjective Breathing Test .............................................................................................................10
Table 1: Troubleshooting Guide..........................................................................................................11
Table 2: List of Tools and Service Kits................................................................................................12
Table 3: Torque Specications............................................................................................................13
Table 4: Checking Specications .......................................................................................................13
Table 5: Recommended Cleaners and Lubricants..............................................................................14
Procedure A: Cleaning and Lubricating..............................................................................................15
Legend, Exploded View......................................................................................................................17

Legend First Stage Technical Maintenance Manual 3
Pinch Method
Press upwards on sides of o-ring to
create a protrusion. Grab o-ring or
insert o-ring tool at protrusion.
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 Aqua Lung America. It may not be distributed through the
internet or computer bulletin board systems without prior consent in
writing from Aqua Lung America.
©2006 Aqua Lung America, Inc.
Legend First Stage Technical Maintenance Manual
Introduction
This manual provides factory prescribed procedures for the correct
service and repair of the Aqua Lung or Apeks regulator products
described in this manual. 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 Authorized training through an
Aqua Lung Service & Repair Seminar. If you do not completely under-
stand all of the procedures outlined in this manual, contact Aqua Lung to
speak directly with a Technical Advisor before proceeding any further.
Warnings, Cautions, & Notes
Pay special attention to information provided in warnings, cautions and
notes that are accompanied by one of these symbols:
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 emphasize important
points,tips and reminders.
Scheduled Service
If the regulator is subjected to less than 50 dives per year, it is
permissible to overhaul it every other year with an inspection
procedure being performed on the “off” years. For example:
Year #1: Inspection
Year #2: Overhaul
Year #3: Inspection
Year #4: Overhaul, and so on.
Both Inspections and Overhauls need to be documented in the Annual
Service & Inspection Record in the back of the Owner’s Manual to keep
the Limited Lifetime Warranty in effect. If a regulator is subjected to more
than 50 dives per year, it should receive the complete overhaul.
An Ofcial Inspection consists of:
1. A pressurized immersion test of the entire unit to check
for air leakage.
2. Checking for stable intermediate pressure that is within
the acceptable range.
3. Checking for opening effort that is within the
acceptable range.
4. Checking for smooth operation of the control knob and
venturi switch.
5. A visual inspection of the lter for debris or discoloration.
6. A visual inspection of the exhaust valve to see that it is in
good shape and that it’s resting against a clean surface.
7. A visual inspection of the mouthpiece looking for tears
or holes.
8. Pulling back hose protectors and checking that the hoses
are secure in the hose crimps.
If a regulator fails item #1,2,3 or 4, the entire regulator should be
overhauled. If a regulator fails 4,5,6 or 7, it will be up to the technician’s
discretion whether or not a full overhaul is required.
General Guidelines
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
before attempting to disassemble the product in this manual, and to
learn which specialty tools and replacement parts will be required.
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. As the regulator is disassembled, reusable components should
be segregated and not allowed to intermix with nonreusable parts
or parts from other units. Delicate parts, including inlet ttings and
crowns which contain critical sealing surfaces, must be protected
and isolated from other parts to prevent damage during the cleaning
procedure.
4. Use only genuine Aqua Lung parts provided in the overhaul parts
kit for this product. DO NOT attempt to substitute an Aqua Lung 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.
7. In order to make the regulator compatible with nitrox up to
40%O2 (EAN40), the regulator must be properly cleaned, lubricated
and assembled using genuine Aqua Lung or Apeks replacement
parts. In addition, assembly must be carried out in a clean
environment using powderless, latex gloves or equivalent. For more
detailed information, be sure to read Procedure A: Cleaning and
Lubrication at the back of this manual.
General Conventions
Unless otherwise instructed, the following terminology and techniques
are assumed:
1. When instructed to remove, unscrew, or loosen a threaded
part, turn the part counterclockwise.
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 illustration below) if possible, or use a brass or plastic o-ring
removal tool. Avoid using hardened steel picks, as they may damage
the o-ring sealing surface. 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; LP is Low Pressure.
5. Numbers in parentheses reference the key numbers on the
exploded parts schematics. For example, in the statement,
“...remove the o-ring (7) from the crown (8)...”, the number 7 is
the key number to the crown o-ring.

4
NOTE:The washer may be inside the adjustment
screw. If so, gently tap the adjustment screw
against the work bench and the washer will
fall out.
DISASSEMBLY PROCEDURE
1. Remove the hoses from the rst stage using the appro-
priate sized wrenches. Install spare HP and MP port plugs
into the empty ports, leaving one MP port and one HP port
open.
2. Using an 8 mm hex key, remove the cap (29) and lift off
the ribbed washer (26).
4. With your ngers, stretch the spacer (25) and slide it off
the spring retainer (21).
3. With your ngers, remove the secondary diaphragm (28).
Turn the rst stage over so the piston (27) falls out into your
hand.
5. Using an 8mm hex key, unscrew and remove the adjust-
ment screw (24). Remove the washer (23). Lift out the main
spring (22).
6. Install a vise mounting tool (p/n 5116230) into one of the
HP ports. Secure the vise mounting tool in a bench vise
with the spring retainer (21) facing upward. Using a 32mm
open-end wrench, unscrew the spring retainer from the
body. Lift out the spring pad (20). Using a brass o-ring tool
(p/n 944022), remove the thrust washer (19a), then remove
the rst stage from the vise.
CAUTION: Use only a plastic or brass o-ring removal
tool (p/n 944022) 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.
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.

Legend First Stage Technical Maintenance Manual 5
7. To remove the diaphragm (19b), insert a low pressure air
nozzle into the open MP port. While holding your thumb over
the diaphragm, inject a small blast of air into the MP port to
pop out the diaphragm. Lift out the pin support (18). Turn the
regulator over and allow the pin (7) to fall out into your hand.
8. Using an 8mm hex key, unscrew the HP plug (1). Turn the
regulator over so the spring (5) and HP seat (6) fall out into
your hand. Separate the spring from the HP seat.
9. Using a brass o-ring tool (p/n 944022), remove the o-ring
(2) from the HP plug (1). Next, remove the o-ring (4) and
backup ring (3) from inside the HP plug.
b. Using circlip pliers (p/n 111100), squeeze the circlip
(32) and remove it from the inlet tting. Turn over the
inlet tting and allow the lter shield (31) to fall out
into your hand.
10. Insert the pin end of seat extractor tool (p/n 109437) into
the center hole on the low pressure side (diaphragm side)
of the rst stage body. While keeping the pin slightly tilted,
press inward to remove the crown (9). Remove the o-ring (8)
from the crown.
11. Disassembly of the yoke version
a. Secure the vise mounting tool into a bench vise with
the yoke facing upward. Unscrew the yoke screw (34)
and remove the dust cap (35) from the yoke screw.
Using a large (15") adjustable wrench, unscrew the
inlet tting (30). Loosen the vise and remove the rst
stage. Remove the vise mounting tool from HP port.
CAUTION: Before proceeding, make sure you are
working over a padded work surface; otherwise,
the crown (9) may be damaged during removal.
CAUTION: DO NOT attempt to pry the diaphragm
out of the rst stage with a metal instrument.
Doing so will permanently damage the seating
shoulder in the rst stage, requiring replacement
of the body.
CAUTION: The slightest scratch or scar across
the sealing surface inside the HP plug may
cause leakage and could prevent the regulator
from achieving a stable lock-up of MP.
c. Insert the plastic end of the seat extractor tool into
the open end of the inlet tting and push out the lter
(13). Remove the lter o-ring (12).

6
Before starting reassembly, perform parts
cleaning and lubrication in accordance with
Procedure A: Cleaning and Lubricating
(p. 15).
REASSEMBLY PROCEDURE
12. Disassembly of the DIN version
a. Secure the vise mounting tool into a bench vise with
the DIN adapter facing upward. Remove the protective
DIN cap (36). Using a 6mm hex key, unscrew the
DIN tting (38) and remove the handwheel (39).
b. Using an 1/8" wooden dowel or similar sized tool,
push the lter (13) out of the DIN tting. Remove
the lter o-ring (12).
13. Loosen the vise and remove the rst stage. Remove
the vise mounting tool from HP port. Using a 4mm hex key,
remove all the port plugs (15 & 17) and o-rings (14 & 16).
THIS ENDS DISASSEMBLY
c. Remove the o-ring (37) from the face of the DIN tting.
14. Pull on the narrow end of the protective sheath (11) and
slide it off the body (10).
2. Install new, lubricated o-rings (14 & 16) on all the port
plugs (15 & 17). Install all the port plugs, except for one HP
port, and tighten them using a 4mm hex key.
3. Install a new, lubricated o-ring (8) onto the crown (9). Slide
the crown onto the seat extraction tool (p/n 109437) with the
sealing edge against the plastic handle. Insert the crown into
the body and press it into place. Use the blunt end of the seat
extraction tool to make sure the crown is properly seated.
1. Slide the protective sheath (11) on the rst stage body
(10). Make sure all the ports and inlet tting opening align
with the holes in the sheath.
NOTE: Before performing any reassembly, it is
important to inspect all parts, both new and those
that are being reused, to ensure that every part
and component is perfectly clean and free of any
dust, corrosion, or blemishes. Before dressing
each o-ring with Christo-Lube®, check to ensure
it is clean, supple, and free of any blemish.
WARNING: Use only genuine Aqua Lung parts,
sub-assemblies, and components whenever
assembling any Aqua Lung product. DO NOT
attempt to substitute an Aqua Lung part with
another manufacturer’s, regardless of any
similarity in shape, size, or appearance.
Doing so may render the product unsafe, and
could result in serious injury or death.

Legend First Stage Technical Maintenance Manual 7
NOTE: Before continuing, closely examine the
back up ring (3). You will note that it has a at
side and a concave side. For correct assembly
the concave side should be against the o-ring
(4), as shown in the picture below.
4. Install the new backup ring into the HP plug (1) with the
concave side facing outward. Install a new, lubricated o-ring
(4) into the HP plug, against the backup ring. Visually inspect
the o-ring to make sure it is seated evenly.
5. Install a new, lubricated o-ring (2) onto the HP plug (1).
7. Insert an 8mm hex key into the HP plug. Insert the plug
into the rst stage body. Push down on the plug to compress
the spring while at the same time turning clockwise to screw
it into the body. Tighten the HP plug until it stops turning. At-
tach an 8mm hex key adapter to an in/lbs torque wrench and
tighten the HP plug to 45 in/lbs.
10. Place the spring pad (20), at side down, in the center of
the diaphragm. Set the main spring (22) on the spring pad.
Place the washer (23) on top of the spring.
8. Turn the regulator over so the medium pressure side
is facing upward. Drop the pin (7) through the center hole.
Place the pin support (18) over the pin. Press on the pin sup-
port a few times. It should feel like a spring-loaded button.
11. Using an 8mm hex key, thread the adjustment screw
(24) into the spring retainer (21) until the rst two threads are
engaged. Thread the spring retainer onto the body until hand
tight.
6. Drop a new HP seat (6), blue sealing side rst, into
the rst stage. Inspect the seat to make sure it is standing
straight. Place the spring (5) over the seat.
9. Press a new diaphragm (19b) into the rst stage body.
Run your nger around the edge of the diaphragm to make
sure it is properly seated. Install the thrust washer (19a) on
top of the diaphragm and make sure it is seated at against
the diaphragm.
O-ring
Backup ring

8
15. Installing the DIN Connector
a. Install a new unlubricated o-ring (37) into the face of
the DIN tting (38).
b. Insert the conical end of the lter (13) into the threaded
end of the DIN tting (38). Install a new unlubricated
o-ring (12) into the end of the DIN tting, around the lter.
14. Installing the Yoke Connector
a. Place the lter shield (31) into the end of the inlet tting.
Using circlip pliers, compress the circlip and install it
into the inlet tting. Inspect the circlip to make sure it is
properly seated.
b. Insert the conical end of the lter (13) into the threaded
end of the inlet tting (30). Install a new, unlubricated
o-ring (12) into the end of the inlet tting, around the
lter.
c. Remove the rst stage from the vise. Hold the rst
stage with the inlet opening facing downward. Pass the
inlet tting (30) through the yoke (33) and screw it into
the rst stage body until nger tight. Secure the rst
stage back in the vise with the yoke facing upward.
Place the inlet tting socket (p/n 111001) over the inlet
tting. Attach a socket extension to a ft/lb torque wrench.
Pass the socket extension through the top of the yoke
and insert it into the socket. Tighten the inlet tting to
18 ft/lbs. Remove the torque wrench and socket.
d. Slide the dust cap (35) over the yoke knob threads with
the Aqua Lung logo facing outward. Thread the yoke
screw (34) into the yoke.
13. Using an 8mm hex key, tighten the adjustment screw
(24) until it is ush with the inside ledge of the spring retainer.
12. Screw a vise mounting tool (p/n 5116230) into the open
HP port and secure it in vise with the spring retainer facing
upward. Using a ft/lbs torque wrench and the spring retainer
socket (p/n 122152) or a 32mm crowfoot, tighten the spring
retainer to 18 ft/lbs.

Legend First Stage Technical Maintenance Manual 9
NOTE:Steps 2 and 3 must be performed while the
regulator is still pressurized.
16. Loosen the vise and remove the rst stage. Remove the
vise mounting tool and reinstall the HP port plug.
ADJUSTING THE FIRST STAGE
1. Attach a MP test gauge (0 to 400 psig, p/n 111610) to a
MP hose and thread the hose into the open MP port. Next,
open the bleed valve. If your test gauge does not have an
overpressure relief valve, then it is vital that a properly ad-
justed second stage is attached to the rst stage to act as an
overpressure valve in the event of a HP leak.
2. Attach the rst stage to a fully charged (2500 to 3000 psi)
cylinder. While closely monitoring the MP test gauge, slowly
open the cylinder valve to pressurize the regulator. Then
slowly turn the knob of the bleed valve clockwise until it is
completely shut.
3. If no leaks are detected, use a 8mm hex key to adjust the
MP by turning the adjustment screw: Turning in the adjust-
ment screw increases the MP; turning out the adjustment
screw decreases the MP. Turn the adjustment screw in 1/8
turn increments and cycle the bleed valve or second stage
purge button several times after each adjustment.
Set the MP to 137±7 psi (standard Legend) or 123±7 psi
(Legend Supreme). Once the MP has been adjusted, cycle
the bleed valve or second stage purge button 10-15 times.
After cycling, watch the gauge needle. The rst stage MP
should "lock-up" and be stable at the desired setting. Make
any further adjustments as necessary. Leave the regulator
under pressure for several minutes and check that the MP
remains stable. If the MP rises more than 5 psi, this indicates
a leak. Refer to Table 1: Troubleshooting Guide, p. 11, for
possible causes.
4. Close the cylinder valve and depressurize the regulator
by opening the gauge bleed valve or by pressing the second
stage purge button. Close the gauge bleed valve and repres-
surize the system. The MP should still read the original MP
setting. If the pressure reading is different than the original
setting, repeat steps 3 and 4 until the MP is stable.
FINAL ASSEMBLY
c. Remove the rst stage from the vise. Hold the rst stage
with the inlet opening facing downward. Insert the
threaded end of the DIN tting through the threaded
side of the handwheel (39) and tighten it into the rst
stage body until nger tight. Secure the rst stage back
in the vise with the DIN tting facing upward. Attach a
6mm hex key adapter to a ft/lb torque wrench and tighten
the DIN tting to 18 ft/lbs.
CAUTION: Before pressurizing the rst stage, it is
important to have a properly adjusted second stage
attached to the rst stage. This will provide a safety
relief valve if the MP exceeds 145 psi. Failure to
relieve increasing MP may result in damage to the
test gauge or the MP hose.
1. Orient the spacer (25) so the side with straight edges is
facing upward. Align the straight edges of the spacer with the
wrench ats on the spring retainer. Work the spacer over the
spring retainer until it sits against the body. Place the ribbed
washer (26) on top of the spacer.
2. With the regulator still pressurized, insert the piston (27)
into the dry chamber. With the cupped side of the second-
ary diaphragm (28) facing downward, insert the edge of the
diaphragm into the outer groove in the spring retainer (21).
WARNING: Be certain not to install a MP hose into
the HP port via an adapter. Doing so may cause the
hose to rupture when pressurized, and could result
in serious personal injury.
WARNING: If the pressure gauge rapidly exceeds
145 psi, thee is a HP leak. Quickly close the cylinder
valve and purge the second stage, or reopen the
bleed valve of the test gauge and close the cylinder.
Failure to do so may cause a rupture to the MP hose
and/or MP gauge, which in turn can lead to personal
injury. Refer to Table 1: Troubleshooting Guide, p. 11
for the causes of high or unstable MP.

10
FINAL TESTING
Immersion Test
1. With the port plugs and at least one properly adjusted
second stage installed, slowly open the cylinder valve and
pressurize the rst stage. Completely submerge the rst
stage in fresh water and check for leaks.
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 sream.
If a leak is detected, note the source of the leak and refer to
Table 1:Troubleshooting Guide, p.11 for possible causes
and corrective actions.
3. Thread the end cap (29) onto the dry chamber until
handtight. Using an in/lbs torque wrench and an 8mm hex
key adapter, tighten the end cap to 35 in/lbs. Recheck the
MP to make sure it is still at 137 psi (standard) or 123 psi
(supreme).
4. Close the cylinder valve and depressurize the regulator.
Remove the test gauge and reinstall the port plug(s).
This Ends Reassembly
Subjective Breathing Test
1. Depress the second stage purge to ensure that the
volume of airow is adequate to clear the second stage.
2. Breathe deeply from the mouthpiece. A properly serviced
and adjusted regulator should deliver a smooth, uninterrupted
airow upon deep inhalation; without excessive effort,
hesitation, or freeow. If any abnormalities or problems occur,
refer to Table 1: Troubleshooting Guide, p. 11.
When completed, close the cylinder valve and depressur-
ize the regulator. Remove the rst stage from the valve and
secure the dust cap in place.
This concludes the service
procedures for the Legend First Stage
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, LP (30 psi) air.
Disassemble and remedy the problem by
referring toTable 1:Troubleshooting Guide, p. 11.

Legend First Stage Technical Maintenance Manual 11
Table 1: Troubleshooting Guide
SYMPTOM POSSIBLE CAUSE TREATMENT
High or Unstable MP
1. The HP seat (6) is worn or damaged. 1. Replace HP seat
2. The crown (9) is damaged. 2. Replace crown
3. The crown o-ring (8) is worn or damaged. 3. Replace o-ring
4. The HP plug (1) internal wall damaged. 4. Replace HP plug
5. The o-ring (4) is damaged. 5. Replace o-ring
6. The body to crown sealing area is
damaged. 6. Replace body
7. The HP plug spring (5) is weakened or
damaged. 7. Replace spring
8. The rst stage is improperly adjusted. 8. Readjust the adjustment screw (24)
External Air Leak
or
Secondary Diaphragm Distended or
Burst
1. The port plug o-rings (14 & 16) are worn
or damaged. 1. Replace o-rings
2. The diaphragm (19b) is worn or damaged. 2. Replace diaphragm
3. The diaphragm seating surface is
damaged. 3. Replace body
4. Spring retainer (21) is loose. 4.Tighten spring retainer
5. The diaphragm (28) is worn or damaged. 5. Replace diaphragm
6. Inlet tting o-ring (12) is worn or
damaged. 6. Replace o-ring
7. HP plug o-ring (2) is worn or damaged. 7. Replace o-ring
Restricted air ow or high inhalation
resistance through entire system
1. The cylinder valve not completely open. 1. Open valve and check cylinder
pressure
2. The cylinder valve needs service. 2. Try another cylinder
3. The lter (13) is clogged. 3. Replace lter
NOTE: This is a partial list of possible problems and recommended treatments.
For more information, refer to the second-stage troubleshooting guide, or contact
Aqua Lung Technical Service Department for assistance with problems
not described here.
CAUTION: Recommended treatments which require disassembly of the regulator
must be performed during a complete overhaul, according to the prescribed
procedures for scheduled, annual service. Do not attempt to perform partial service.

12
PART # DESCRIPTION APPLICATION
111610 Checking medium pressure
944022 Removing and installation of o-rings
111100 Removing circlip (5)
111001 Apply proper torque to inlet tting
122152 Apply proper torque to spring retainer
N/A Use with inlet tting and spring retainer sockets to apply
proper torque
109437 Crown (14) assembly/disassembly
5116230 For holding rst stage in vise
N/A Torque Wrench ft/lbs and in/lbs Apply torque to parts listed in
Table 3: Torque Specication, p. 13
N/A Loosen/tighten/adjust parts
N/A Apply torque to parts listed in
Table 3: Torque Specication, p. 13
Table 2: List of Tools and Service Kits
Seat Extraction Tool
Vise Mounting Tool
O-ring Tool
Reversible Circlip Pliers
MP Gauge 0-400 psi
Inlet Fitting Socket
Spring Retainer Socket
3" Socket Extension
Hex Key (4mm 6mm 8mm)
Hex Key Adapter (4mm 6mm 8mm)

Legend First Stage Technical Maintenance Manual 13
PART # DESCRIPTION APPLICATION
N/A Loosen/tighten/adjust parts
N/A 15" Adjustable Wrench Loosen parts
N/A Apply torque to parts listed in
Table 3: Torque Specication, p. 13
N/A Magnier w/Illumination Sealing surface and spring inspection
N/A Ultrasonic Cleaner Brass & stainless steel parts cleaning
900014 Service Kit LEGEND
Table 3: Torque Specications
PART # DESCRIPTION / KEY ITEM # TORQUE
129122 Spring Retainer (21) 18 ft/lbs
129124 Inlet Fitting (30) 18 ft/lbs
124602 DIN Connector (38) 18 ft/lbs
129120 HP Plug (1) 45 in/lbs
129118 HP Port Plug (15) or hose 40 in/lbs
129119 MP Port Plug (17) or hose 40 in/lbs
129194
129196 Cap (29) 35 in/lbs
Table 4: Checking Specications
TEST CONDITION SPECIFICATION
Leak Test Inlet 2,500-3,000 (±100) psi No leaks allowed
MP Inlet 2,500-3,000 (±100) psi 137±7 psi (standard)
123±7 psi (supreme)
MP creep Inlet 2,500-3,000 (±100) psi 5 psi max between 5 to 15 seconds
after cycling regulator (purge)
Open-end Wrench
(1/2", 9/16", 5/8")
(26mm, 32mm)
Crowfoot
(26mm, 32mm)
(1/2", 9/16", 5/8")
Table 2: List of Tools and Service Kits

14
Table 5: Recommended Cleaners and Lubricants
LUBRICANT/CLEANER APPLICATION SOURCE
Christo-Lube MCG 111 All o-rings
Aqua Lung, PN 820466, or
Lubrication Technologies
310 Morton Street
Jackson, OH 45640
[phone]
Oakite #31 Acid bath for reusable stainless steel and
brass parts.
Oakite Products, Inc.
50 Valley Road
Berkeley Heights, NJ 07922
White distilled vinegar Acid bath for reusable stainless steel
and brass parts. “Household” grade
Liquid dishwashing detergent
(diluted with warm water)
Degreaser for brass and stainless steel
parts; general cleaning solution for plastic
and rubber
“Household” grade
CAUTION: Silicone rubber requires no lubrication or preservative treatment.
DO NOT apply grease or spray to silicone rubber parts. Doing so may cause
a chemical breakdown and premature deterioration of the material.
CAUTION: Do not use muriatic acid for the cleaning of any parts. Even if
strongly diluted, muriatic acid can harm chrome plating and may leave a
residue that is harmful to o-ring seals and other parts.

Legend First Stage Technical Maintenance Manual 15
Aqua Lung and Apeks First Stages and Nitrox
When it comes to issues of nitrox safety and compatibility, the concerns lie primarily with the rst stage as it is subjected to high inlet
pressures. High inlet pressures lead to adiabatic compression or heating of the gas. The Aqua Lung or Apeks regulator product
described in this manual, when properly cleaned and assembled, is authorized for use with enriched air nitrox (EAN) that does not
exceed 40% (EAN 40). It is authorized because it has undergone adiabatic compression testing and the authorized service kit
components and lubricants are compatible in elevated oxygen environments. During cleaning, a mild detergent must be used to remove
condensed hydrocarbons (compressor oils) from the inside passageways of the rst stage. For the rst stage to remain EAN40
compatible, only use hyper ltered compressed gas (hydrocarbons < 0.1 mg/m3). Ordinary compressed breathing air (Grade E) usually
does not meet this criterion. Once ordinary breathing air is used, the rst stage is no longer EAN40 compatible until it is cleaned and
serviced again.
Although regulator second stage components are not exposed to high pressure EAN, Aqua Lung 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.
Cleaning Brass and Stainless Steel Parts
1. Preclean in warm, soapy water* using a nylon bristle tooth brush.
2. Thoroughly clean parts in an ultrasonic cleaner lled with soapy water. If there are stubborn deposits, household white distilled
vinegar (acetic acid) in an ultrasonic cleaner will work well. DO NOT place plastic, rubber, silicone or anodized aluminum 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) ltered air, and inspect closely to ensure proper cleaning and like-new condition.
Cleaning Anodized Aluminum, Plastic & Rubber Parts
Anodized aluminum parts and parts made of plastic or rubber, such as box bottoms, box tops, dust caps, etc., 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.
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 Hoses
1. Hose ttings: Ultrasonically clean with soapy water*; vinegar OK on tough corrosion
2. Run soapy water through hose if needed
3. Thoroughly rinse with fresh water
4. Blow out hose before installing
Lubrication and Dressing
Wear powderless, latex gloves when handling and lubricating o-rings. Keeping internal parts free from skin oils and other contaminates
is important when running enriched air nitrox through a rst stage. All o-rings should be lubricated with Christo-Lube®MCG-111. 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 Christo-Lube grease, as this will attract particulate matter that may cause damage to the o-ring.
*Soapy water is dened as “household” grade liquid dishwashing detergent diluted in warm water.
Procedure A: Cleaning and Lubricating

16
Maintenance Notes

Legend First Stage Technical Maintenance Manual 17
Legend Series
5
6
43
2
20
14
13
12
987
37
38
33
34
30
31
32
Key # .Part # Description Key # .Part # Description
.......129060 First Stage Complete
.......129015 DIN Connector, Legend
.......129226 ACD Conversion Kit, Yoke
.......129227 ACD Conversion Kit, DIN
.......900014 Overhaul Parts Kit (Yoke and DIN)
1 .......129120 HP Plug
2 .......824407 O-ring
3 .......119129 Backup ring
4 .......820080 O-ring
5 .......122244 Spring
6 .......105940 HP Seat
7 .......102002 Pin
8 .......820038 O-ring
9 .......106027 Crown
10 .......129111 Body
11 .......129112 Protective Cover
12 .......820011 O-ring
13 .......129151 Filter
14 .......820072 O-ring, HP Port
15 .......129118 Port Plug, HP
16 .......820011 O-ring, LP Port
17 .......129119 Port Plug, MP
18 .......129121 Pin Support
19 .......103425 Diaphragm Kit (includes thrust washer 19a
and diaphragm 19b)
20 .......124560 Spring Pad
21 .......129122 Spring Retainer
22 .......106356 Main Spring
23 .......845097 Washer
24 .......106026 Adjustment Screw
25 .......129128 Spacer
26 .......129127 Ribbed Washer
27 .......129123 Piston
28 .......129126 Diaphragm, Secondary
29 .......129194 Cap, Black
.......129196 Cap, Chrome
30 .......129124 Inlet Fitting
31 .......129149 Shield
32 .......863051 C-Clip
33 .......124613 Yoke, Black
.......106843 Yoke, Satin
.......124611 Yoke, Bright Chrome
34 .......107507 Yoke Screw
35 .......124555 Dust Cap
36 .......107441 DIN Cap
37 .......820094 O-ring
38 .......129125 DIN Fitting
39 .......129117 DIN Handwheel
Part numbers in BOLD ITALICS indicate standard overhaul replacement part.
1
11
15
16
17
18
21
22
23
24
29
35
39
36
10
28 27
26
25
19
ab

Authorized Technician
TECHNICAL MAINTENANCE MANUAL
LEGEND FIRST STAGE
Aqua Lung America
2340 Cousteau Court, Vista CA 92081
760-597-5000
www.aqualung.com
©2006 Aqua Lung USA Rev. 6/2006