Sherwood Scuba maximus SRB5600 Quick guide

Assembly & Maintenance Guide
(SRB5600)
®
®
REGULATORS

FIRST STAGE - MAXIMUS™ SRB5600
The model number of the regulator is laser stamped on the first stage between two of the outlet ports.
ITEM # CATALOG # DESCRIPTION
1 . . . . . . . . . . .5105-70 . . . . . . . . .Handwheel
2 . . . . . . .J2790056B . . . . . . . . . .Filter Retaining Ring
3 . . . . . . . . . . .1390-7 . . . . . . . . .Filter
4 . . . . . . . .29-5305-4 . . . . . . . . . .Moving Orifice
(bare, no O-rings)
5 . . . . . . . .19-8010-8 . . . . . . . . . .Belleville Spring Washers
(5 needed)
6 . . . . . . . . . .G007A . . . . . . . . . . .O-ring
7 . . . . . . . . MS28774-007 . . . . . . .White Backup Washer
8 . . . . . . . . . . .5705-20 . . . . . . . . .Dust Cap
9 . . . . . . . . .1-1665-17 . . . . . . . . .Yoke Nut
10 . . . . . . .70-1665-26 . . . . . . . . .Yoke
11 . . . . . . . . .G904A . . . . . . . . . .O-ring (for H. P. port plug)
12 . . . . . . . .1-3405-4 . . . . . . . . . .H. P. Port Plug
13 . . . . . . . .70-5705-1 . . . . . . . . . .Body
14 . . . . . . . . .G011B . . . . . . . . . . .O-ring (for L.P. Port Plugs)
15 . . . . . . . . . .3106-6 . . . . . . . . .One Way Bleed Valve
16 . . . . . . . .1-3105-6 . . . . . . . . . .L. P. Port Plug
17 . . . . . . . . . .5105-6 . . . . . . . . .Gasket for Flow Control Element
18 . . . . . . . . . .5105-15 . . . . . . . . .Restrictor Assembly
18 . . . . . . . . . .5105-13 . . . . . . . . .Flow Restrictor Screw
18 . . . . . . . . . .5105-14 . . . . . . . . .Filter
19 . . . . . . . . . .5105-12 . . . . . . . . .Main Spring
20 . . . . . . . . . .5105-PK . . . . . . . .Shim (to raise hose pressure)
21 . . . . . . . . .G007A . . . . . . . . . . .O-ring (for small end of piston)
22 . . . . . . . . . .3801-5 . . . . . . . . .Piston Seat
23 . . . . . . . . . .5105-3 . . . . . . . . .Piston (bare, no seat or O-rings)
24 . . . . . . . . .G022A . . . . . . . . . . .O-ring (for large end of piston)
25. . . . . . . . .G025A . . . . . . . . . . .O-ring (for cap)
26 . . . . . . . .70-5305-2 . . . . . . . . . .Cap
27 . . . . . . . . . .5700-15 . . . . . . . . .Cap Label
28 . . . . . . . . . .5705-21PE . . . . . .Trim Ring

TABLE OF CONTENTS
Page
1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
2.0 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
2.1 SRB5600 (Maximus) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
3.0 O-rings Reference Chart . . . . . . . . . . . . . . . . . . . . . . . . . . .4
4.0 First Stage Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
4.1 Tools Required for First Stage Servicing . . . . . . . . . . . . . . . .5
4.2 Disassembly of First Stage . . . . . . . . . . . . . . . . . . . . . . . . . .5
4.3 Assembly of First Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
4.4 Testing of First Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
5.0 Second Stage Procedures . . . . . . . . . . . . . . . . . . . . . . . . .12
5.1 Tools Required for Second Stage Servicing . . . . . . . . . . . . . .12
5.2 Disassembly of Second Stage . . . . . . . . . . . . . . . . . . . . . . . .12
5.3 Assembly of Second Stage . . . . . . . . . . . . . . . . . . . . . . . . . .14
5.4 Set-Up of Second Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
5.5 Testing of Second Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
6.0 Helpful Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
6.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
6.2 Parts Cleaning Recommendations . . . . . . . . . . . . . . . . . . . . .22
6.3 Commonly Used Cleaning Solutions . . . . . . . . . . . . . . . . . . .22
6.4 Handling Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
7.0 Two Year Warranty and Maintenance Information . . . . . . .24
7.1 Proper Procedure for Warranty Paperwork . . . . . . . . . . . . . .24
7.2 Scheduled Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
BEFORE YOU BEGIN.....
READ THESE INSTRUCTIONS COMPLETELY BEFORE YOU BEGIN SERVICING THE
REGULATOR.
THESE INSTRUCTIONS ARE INTENDED FOR PEOPLE WHO HAVE BEEN AUTHORIZED BY
SHERWOOD TO REPAIR SHERWOOD SCUBA EQUIPMENT. IF YOU ARE NOT SO
AUTHORIZED - STOP.

1
1.0 INTRODUCTION
1. The procedures in this manual apply to the Sherwood Scuba SRB5600 Maximus regulator
only. The older SRB3600 Maximus regulator has different parts and service procedures. The
SRB3600 has its own service manual. The correct service manual for the two models can be
determined by looking at the cover picture of the regulator. The most current part numbers can
be obtained by referring to the dealer price guide, or calling your Sherwood Sales
Representative.
All current Sherwood Scuba Regulators have service kits available which contain the parts
which must be changed at every annual service no matter what their condition. The standard
annual service kit for the Maximus is 4000-4. All other parts not contained in this kit must be
inspected by the technician and changed under warranty only if they have failed due to
problems with material or workmanship.
2. This manual gives breakdowns of regulator parts, equipment specifications, servicing
instructions, troubleshooting recommendations, and guidelines for proper care of the SRB5600
Maximus regulator. This manual is intended for use only by persons specially trained and
authorized to service Sherwood Scuba equipment.
3. Anyone attempting to service or repair Sherwood Scuba regulators must have a thorough
understanding of the principles of operation of scuba regulators and valves, as well as the
appropriate mechanical ability. The technician must be properly trained in the safe use of
compressed air and the various tools and cleaning solutions involved in the procedures
outlined in this manual.
4. The best source for current part numbers for any of the parts listed in this manual is your
current parts and price list from Sherwood.
5. Because of the many unique features found in Sherwood regulators, Sherwood conducts
seminars on a regular basis throughout North America to train technicians in proper service and
repair procedures for all current Sherwood regulators. In addition, all Sherwood dealers and
their staff members are encouraged to attend the seminars to gain an in-depth understanding
of the construction, special features and operation of Sherwood regulators. For information on
the dates and locations of upcoming Sherwood service seminars near you, contact
Sherwood or your Sherwood Sales Representative.
NOTE : You must be authorized by Sherwood to wor on Sherwood Scuba equipment. You can obtain
proper authorization by attending all appropriate seminars given in your area. This is the only way you can
become an authorized Sherwood technician.
NOTE : Oxygen Enriched Air conversion its are available for all current Sherwood regulators and valves.
The part number for the model covered in this manual is 4000-15N. These its are to be installed into
properly cleaned and prepared regulators only by technicians trained by one of the major oxygen enriched
air training agencies.
WARNING
Proper torque for the hose fittings is 40 in. lbs. (4.5 joules). NEVER tighten the hose fit-
ting to the first stage with more than 45 in. lbs. (5 joules) of torque. The inlet hose fitting
can be weakened by overtightening. Failure of the fitting could cause air loss resulting
in death, personal injury, or property damage.

6. Companion instructional VHS videotapes to this and other Sherwood Scuba repair manuals are
available from Sherwood Scuba at a nominal cost. Ask your Sherwood Scuba Sales
Representative for details.
7. If you have any questions, or need more information, contact your Sherwood Scuba Sales
Representative.
2

2.0 SPECIFICATIONS
2.1 SPECIFICATIONS FOR THE SRB5600 MAXIMUS
REGULATOR MODEL: Sherwood SRB5600 Maximus
AIR FLOW: 33 cu. ft. (935 liters)/min. @ 1 atmosphere
INHALATION RESISTANCE: .9" - 1.5" (2.3 - 3.8 cm) w.c @ 1 atmosphere (adjustable)
EXHALATION RESISTANCE: 0.7" (1.8 cm) w.c. max. @ 1 atm.
RECOMMENDED LUBRICANT: Christo-Lube® MCG111 (Sherwood p/n SW-MS150)
A. First Stage Regulator:
TYPE: Flow-by piston with Moving Orifice Balancing, Dry Air
Bleed, and Air Sensing Channel Boost –U.S. Pat. #
4,226,257, U.S. Pat. #5,662,100
WEIGHT: 1 lb. 11 oz. (.77kg)
INTERSTAGE PRESSURE: 135 -150 psi (9-10 bar)
MAXIMUM INLET PRESSURE: 300 bar ( with 300 bar DIN adapter )
POSITIVE AIR PURGE
FLOW RATE: 13-27 cc/minute
# LOW PRESSURE PORTS: 5 (3/8"-24 UNF)
# HIGH PRESSURE PORTS: 2 (7/16"-20 UNF)
MATERIALS: Body –CDA-36000 Brass
O-rings –Buna-N (Viton Nitrox o-ring kit available)
Bleed Valve –Ethylene Propylene
Piston Seat –Teflon®
B. Second Stage Regulator:
TYPE: Downstream valve, diaphragm, Variable Fulcrum –
U.S. Pat.#3,991,785 other Pat. pending
WEIGHT: 7.1 oz. (.22 kg) ( w/o hose)
HOSE LENGTH: 41 in. (1.04 m)
MATERIALS : Cover –Thermoplastic vinyl
Case –Thermoplastic Triax®
Poppet Seat –Buna-N
O-Rings –Buna-N
Diaphragm –Tufel®(clear blue)
Exhaust Valve –Thermoplastic elastomer (blue)
Mouthpiece –Liquid Silicone
3

3.0 O-RINGS REFERENCE CHART
1. Before you begin disassembly of the regulator, test the first and second stages for output
pressures and leakage. Pre-testing in this way will help the technician to pinpoint any specific
problems requiring repair.
2. The work area must be clean and well lighted, with clean compressed air available to blow
sand and dirt from parts.
4

4.0 FIRST STAGE PROCEDURES
4.1 TOOLS REQUIRED FOR FIRST STAGE SERVICING
–Bench vise
–3/32" Allen wrench
–5/32" Allen wrench
–6" or 8" adjustable wrenches
–15" adjustable wrench
–Phillips screwdriver
–#10 Torx screwdriver
–Sherwood 50 cc Graduated Cylinder (p/n TL110)
–Sherwood Piston Seat Removal Tool (p/n TL112)
–Sherwood Plastic Probe (p/n TL111) to push out orifice
–Sherwood Regulator Support Handle (p/n TL113)
–Sherwood Intermediate Pressure Gauge (p/n TL119)
–Annual Service Kit #4000-4 (same as older style Maximus)
–Nitrox Conversion Kit #4000-4N
–Christo-Lube®(p/n SW-MS150), 2 oz. tube of oxygen compatible lubricant
4.2 DISASSEMBLY OF FIRST STAGE
To view all the parts used in the first stage, fold out the front cover of this manual. The
circled numbers below refer to the corresponding numbers on the drawing.
1. Use 6" or 8" adjustable wrenches to disconnect all hoses from the first stage. Pull back the
hose protector from the inlet end of the hose. Inspect the hoses for wear. Pay particular attention
to the area where the metal ferrules meet the rubber hose material. Replace hoses if necessary.
2. Unscrew and remove the handwheel .
3. Remove the dust cap .
5
NOTE : For more information on Sherwood tools and their uses, see Sherwood’s Tools, Repair Kits and
Accessories - Assembly & Maintenance Guide, available from Sherwood.
1
8

4. Install a Sherwood regulator support handle (p/n TL113) into one of the low-pressure ports. Use
the support handle and a 15" adjustable wrench or bench vise to loosen the yoke nut from
the body . See Photo #1.
5. Remove the yoke and yoke nut from the body.
6. Use a 5/32" Allen wrench to remove all remaining port plugs from the body.
7. Use the Sherwood regulator support handle and a 15" adjustable wrench or a bench vise to
remove the cap from the main body. The trim ring will slide off at this time.
8. Remove the spring , any shims , and the piston assembly from the cap. Remove
both piston O-rings and discard them.
9. Remove the piston seat by pushing through the stem with the Sherwood piston seat
removal tool (p/n TL112) from the large end. The seat will then pop out. Discard the old seat.
10. Using a 3/32" Allen wrench, remove the flow control element assembly from inside the large
end of the main body. There are two styles of flow control assemblies. The old style with a
sintered stainless steel flow restrictor and the new style flow restrictor that is laser drilled P/N
5105-13 with a white filter P/N 5105-14. The new style complete assembly part number is
5105-15. If the regulator has the old style flow restrictor and it is functioning (13 to 27 cc/min) it
can be reused, however if it needs to be replaced use the new style. The black gasket can be
reused. The new style restrictor can be cleaned if it becomes plugged. Remove the white filter
and discard it. The white filter must be replaced P/N 5105-14. The laser drilled flow restrictor
can be cleaned in an ultrasonic cleaner and reused. The flow requirement for the new flow
control assembly is 20 to 30 cc/min.
6
Photo #1
10 9
9
12 16
26 28
20 23
22
18
19
13

Note: If no air is bubbling from the one-way bleed valve, this is a good indication that the
positive air purge system is not working.
11. Use a pocket screw driver to remove the black washer that was beneath the element
assembly. Save this washer as it can usually be reused. Be careful not to scratch the metal
surface under the washer.
12. Use a pocket screwdriver to remove the retaining ring or star washer that holds the inlet
filter in place. Always discard the used inlet filter. The retaining ring is saved for reuse.
13. Remove the moving orifice assembly from the body by pushing it with the Sherwood plastic
probe (p/n TL111) from the large threaded end of the body. Catch the orifice assembly in your
hand as it comes out the yoke nut thread end of the body. Carefully inspect the disc springs
for any cracks. Replace all five disc springs if any cracks are found.
14. Remove the one way bleed valve from the body with your fingers or a soft plastic probe.
DO NOT use a metal screwdriver or blade since this will scratch the sealing surface against
which the bleed valve seals. A scratch may allow water to enter the first stage spring chamber
during use.
7
17
2
3
4
5
15
Photo #2

The sealing surface on the body where the one-way valve seals must be totally clean of
deposits. If any deposits remain on the sealing surface after initial cleaning, take a fine abrasive
polishing stick or and polish the surface to remove deposits (see Photo #3).
15. Blow all residue from the body after polishing.
16. Remove the large O-ring from the cap . This O-ring can usually be reused.
17. If necessary, clean all metal parts of the first stage except the flow control element assembly
in an ultrasonic cleaner or cleaning solution. Remove the O-rings before cleaning any metal
parts; most cleaning solutions can damage the O-ring material. See Section 6.3 for
recommendations on cleaning solutions. If major visible corrosion or deposits exist on parts,
use a bristle brush, wooden, or plastic stick to rub the deposits off. Allowing acidic cleaning
solutions to do all of the work if deposits are severe, will result in damage to internal chrome
plating which will make parts even more susceptible to future corrosion.
18. Remove the regulator parts from the cleaning solution. Blow all internal passageways dry with
clean, dry compressed air.
19. Inspect the bores in which the piston and orifice O-rings move for corrosion or wear. If the
bores are leaking air because of wear, replace the parts. If some corrosion deposits persist,
carefully wipe them away with a plastic scrubbing cloth. Blow any resulting dust out of the
regulator parts.
20. Remove and discard the black O-ring from the moving orifice . Save the white backup
washer; it can be reused. Inspect the moving orifice’s sealing surface (located at the top edge
of the orifice cone). Any nicks, scratches, or corrosion at the top of the cone can allow air to
pass, which will result in creeping hose pressures. Polish out the defects using a fine abrasive
polishing stick or pencil eraser. When polishing, apply a light pressure to prevent excessive
wear on the cone. Use compressed air to blow away any dust created by the polishing
process.
8
Photo #3
25
18
4
26

4.3 ASSEMBLY OF FIRST STAGE
1. The part number for each regulator kit can be found in Sherwood’s Tools, Repair Kit and
Accessories – Assembly & Maintenance Guide. The kits contain the parts that are always
replaced at every annual service interval. The kit number for the Maximus is 4000-4. For Nitrox
use, the kit # is 4000-4N.
2. Before installing new O-rings on the piston and moving orifice, lubricate the O-rings with
Christo-Lube MCG111 (Sherwood p/n SW-MS150). Installation of the small O-ring on the
piston is made much easier by using the white-colored Sherwood O-ring installation cone (p/n
TL109). Place the cone over the tip of the piston. Slide the lubricated O-ring over the cone until
it slips into the piston groove.
3. Place the new piston seat on a clean piece of paper on a hard flat surface. Press the piston tip
firmly over the seat until it is fully installed. The piston is now rebuilt and ready for installation.
4. Use the Sherwood installation cone to prevent damage to the new O-ring during installation
onto the moving orifice. Use the green O-ring installation cone (p/n 28-TL107) to install first the
new O-ring and then the used backup washer onto the groove on the moving orifice.
Position them so that the black O-ring is closest to the wide end of the moving orifice.
5. Using a greased soft probe, lightly lubricate the first 1/8" of the small bore in the body
where the small piston and moving orifice O-rings seal.
6. With your finger, push the moving orifice assembly, pointed orifice end first, into the yoke end
of the main body as far as possible. Place the inlet filter , rough side up, on top of the
moving orifice. Place the retaining ring or star washer on top of the filter. Push the retaining
ring or star washer firmly into place with a dowel or screwdriver.
7. Install the used black washer into the hole in the main body where the flow element is
placed. A new washer may be installed if necessary.
8. Install the flow control element into the main body. Tighten the element with a 3/32" Allen
wrench with a torque of 3 in. lbs. (.4 nm). Do not overtighten.
9. Replace the cleaned and lightly lubricated O-ring on the cap .
10. Install the piston assembly squarely into the cap . If any shims were found when the
regulator was disassembled, place them over the piston stem. Then place the main spring
over the piston stem. Install the trim ring onto the body.
11. Install the cap assembly onto the body. Hand-tighten the assembly as tightly as possible, then
install the Sherwood regulator support handle into one of the low pressure ports. Using a 15"
adjustable wrench or a bench vice to hold the cap, tighten the cap onto the body until it
bottoms on the thread. Do not tighten further.
12. Using your index finger, install the clean and dry one-way bleed valve into the body.
13. Lightly lubricate the body yoke nut threads with grease, and install the yoke and the yoke
nut onto the body.
9
21
67
13
3
2
18
17
25
23 26
28
15
10
9
26
19
NOTE : If you use the bleed valve with the Sherwood logo molded into it P/N 3106-6 you will notice a
"dot" molded near the right side of the logo. Install the bleed valve with the "dot" oriented closest to the
inlet of the regulator (towards the yo e).

14. Using the regulator support handle (p/n TL113) in one of the LP pressure ports of the body and
a 15" adjustable wrench, tighten the yoke nut snugly (see Photo #1).
15. Install the handwheel and the dust cap onto the yoke.
16. If the first stage has a SAA-5300 DIN adapter installed instead of a standard yoke, see the
installation instructions given in Sherwood Technical Bulletin #104 for overhaul and installation
instructions of the DIN adapter.
4.4 TESTING OF FIRST STAGE
A. Before You Begin Testing
1. Install an intermediate pressure test gauge (p/n TL119) into one of the low pressure ports of the
first stage. Plug any open outlet ports with suitable port plugs.
2. Install the first stage onto a tank valve, and introduce 2700 - 3500 psig (186-240 bar) to the
inlet of the regulator. Flow air through the regulator by pushing the purge button on the second
stage several times to get all parts properly seated.
B. Dry Air Bleed Flow Test
1. Submerge the first stage under several inches of water.
2. A small stream of bubbles should be escaping from the one-way bleed valve on the first stage
and nowhere else on the body (see Fig. 1). The number and size of the bubbles may vary from
regulator to regulator. To check this, use the following steps:
a. Invert a small (50 cc capacity) graduated cylinder (p/n TL110) filled with water over the
underwater flow of bubbles (see Fig. 1). The air entering the cylinder will gradually empty
some of the water out of the cylinder.
b. After one minute, remove the graduated cylinder from the air flow and raise the cylinder to
the surface so that air/water dividing line inside the cylinder matches the water level outside
the cylinder. The measurement at this point should be between 13 and 27 cc for the old
style flow control element and 20-30 cc for the new laser drilled flow control element.
c. If the reading is significantly higher than 30cc check the O-rings and sealing surfacesmated
to the piston. If the reading is below 13cc, check the flow control element to determine if
it has been clogged by grease or other foreign matter. If it is clogged, it must be replaced
(old style sintered stainless steel ) or cleaned (new laser drilled element).
10
NOTE : For safety, always test the first stage regulator with at least one second stage installed.The
demand valve on the second stage acts as a relief valve in the event of a malfunction.
18
1 8

C. Intermediate Pressure Test
1. Attach any Sherwood second stage to one of the low pressure ports, and the Sherwood
intermediate pressure gauge (p/n TL119) to another low pressure port. Plug all other ports with
appropriate port plugs.
2. Attach the regulator to a tank valve giving a source pressure of between 2700 and 3500 psig
(186 and 240 bar).
3. Turn the supply air on slowly while listening for any unusual air leaks. If any are heard, turn
the air off immediately and determine the source of the leak. If no leaks are found, watch the
pressure gauge reading rise as you continue turning the air on slowly. It should stop around
145 psig (10 bar).
4. If the pressure gauge continues to rise above 155 psig (10.4 bar), turn the air supply off
immediately and inspect the regulator to determine the cause.
5. Once the air pressure stops rising, the internal parts should be worked into place by allowing
air to escape from the second stage several times by pushing the purge button.
6. If you have depressed the purge button several times and the pressure is below 135 psig (9.3
bar), you can add shims to increase the pressure. Do not use more than three shims.
7. If the pressure is too high (above 150 psig or 10.3 bar), remove the necessary shims.
8. After the correct pressure has been reached, let the regulator sit for several minutes and then
depress the purge button again to check that the regulator returns to the proper pressure.
Never set the output pressure of the first stage above 150 psig (10.3 bar).
11
20
NOTE : This test determines the regulator’s loc -up pressure (the pressure put out by the first stage during
a no-flow condition).

5.0 SECOND STAGE PROCEDURES
5.1 TOOLS REQUIRED FOR SECOND STAGE SERVICING
–Two good quality 6" or 8" (15 or 20 cm) adjustable wrenches
–#10 Torx screwdriver
–Side cutting pliers
–Sherwood Plastic Probe (p/n TL111) to push out orifice
–Sherwood Lever Height Adjusting Tool (p/n TL123)
–Small Phillips screwdriver
–Small slotted screwdriver
–Size "0" square drive screwdriver (e.g. Channel Lock p/n SL-0)
–Locktite 242®(mild thread locking adhesive)
–Christo-Lube®(p/n SW-MS150), 2 oz. tube of oxygen compatible lubricant
5.2 DISASSEMBLY OF SECOND STAGE
To view the complete parts list of the second stage, fold out the back cover of this manual.
1. Remove the hose assembly from the swivel fitting . Inspect the hose assembly for
any cuts or cracks, especially on the hose at the metal ferrules. Replace the hose assembly if
any cuts or cracks are found.
2. Remove the mouthpiece by cutting the mouthpiece tie with side cutting pliers. Discard
the old mouthpiece tie. Examine the condition of the mouthpiece. Pay particular attention to
the area on top just behind where the old tie tightened. This is a prime area for small holes to
develop. If the mouthpiece is in good condition, it can be reused.
3. Remove the exhaust tee retaining screws with a #10 Torx or slotted screwdriver.
4. Remove the exhaust tee from the case by pulling it back and off the top edge.
5. Using a size 0 Square Drive Screwdriver (preferred) or a small Phillips Screwdriver, loosen and
remove the screw and washer from the orifice Adjusting Knob .
6. Remove the adjusting knob from the end of the adjusting orifice.
12
10
21
28
38
567
WARNING
Proper torque for the hose fittings is 40 in. lbs. (4.5 Joules). NEVER tighten the hose
fitting to the first stage with more than 45 in. lbs. (5 Joules) of torque. The inlet hose
fitting can be weakened by overtightening. Failure of the fitting could cause air loss
resulting in death, personal injury or property damage.
3
22

13
7. Using a small slotted screwdriver, remove the cir-clip from the adjusting orifice .
8. Use a 5/8" wrench to remove the retainer nut from the orifice housing . Hold the base of
the orifice housing with a 3/4" wrench while doing this.
9. Remove the swivel fitting from the orifice housing. Inspect the inner sealing surfaces for
scratches that might cause leaks.
10. Remove the cover from the case by pushing on the front top edge firmly enough to cause
the top lip of the cover to curl outwards. Use fingers to grasp the exposed lip of the cover.
Slide the cover assemble off of the orifice housing.
11. Remove the diaphragm retaining ring from the case using fingers.
12. Gently remove the diaphragm from the case. Hold the diaphragm up to a light source.
Gently stretch the diaphragm and look for tears or pinholes. If any are found, replace the
diaphragm. Otherwise, the diaphragm can be reused. If you are repeatedly tearing diaphragms
during this visual inspection, you are using too much force. You cannot return diaphragms torn
in this way for warranty credit.
13. Remove the adjusting lever from the case by using a small slotted screwdriver to slide the
retainer clip , off the adjusting lever. Slide the adjusting lever out of the case . The
adjusting lever and o-ring can usually be cleaned by hand in warm soapy water,
relubricated, and reused with the o-ring in place. However, if the o-ring shows excessive
wear it can be removed and discarded at this time. Use a blunted dental pick or similar object
to remove the o-ring if removal is necessary. Take care not to gouge the o-ring groove during
this procedure.
14. Use a 6" or 8" (15 or 20 cm) adjustable wrench to loosen and remove the orifice housing .
The case assembly has been reinforced to allow doing this without holding the lever support
with another wrench.
15. Remove the lever support and assembly from the case with the heat transfer fins &
still attached. There is no reason to remove these fins from the lever support during a normal
service interval. If the fins do have to be removed for some reason, a small Phillips ACR
screwdriver can be used to remove and replace the screws .
16. Normally, along with cleaning, you will simply need to change the poppet stem seat insert
and polish the orifice seal , to restore the second stage to maximum performance. To
change the stem seat insert , leave the lever assembly together. With a pick or similar
object, carefully remove the old seat insert. Put the new seat insert on a clean flat surface and
lower the poppet cavity (from which the old seat insert was removed) over the new seat insert.
The new style black molded seat (p/n 978-9BN) should be installed with the identifying
Sherwood symbol facing outward.
17. If parts of the lever assembly (stem, spring, lever, etc.) need to be replaced, it can be done with
a minimum number of tools. With the original poppet seat in place, and the orifice
installed in the orifice housing , screw the orifice housing and lever support together
(without the case) until the lever begins to droop. Use a #10 Torx screwdriver to remove the
screw . Unscrew the orifice housing and lever support, and the poppet and spring will be
exposed for replacement. Reverse the procedure to install the new parts. Remember to use the
old seat to perform this procedure since the seat is likely to be damaged due to excess friction.
Install a new seat when you have reassembled the lever assembly.
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32 34 35
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18. Hold the orifice housing in one hand. Temporarily install the adjuster knob and use it to
turn the orifice clockwise until it comes out of the orifice housing. Remove and discard the
o-rings on the orifice & , and the orifice housing & .
19. Before removing the exhaust valve from the case, bend it over as far as it will go from the
top, bottom, left and right sides. If it fails to snap back quickly, and does not lie perfectly flat
against the case, the valve should be replaced. If it does snap back satisfactorily, remove it and
inspect the sealing edges. If they appear smooth, and the locking tab on the nipple is good, the
valve can be reused.
20. Rinse all plastic and silicone parts in clean fresh water, and then blow the parts dry with
compressed air to remove any sand and dust particles.
21. If necessary, clean all metal parts of the second stage in an ultrasonic cleaner or cleaning
solution. Remove the o-rings before cleaning any metal parts; most cleaning solutions are
damaging to the o-ring material. See Section 6.3 for recommendations on cleaning solutions.
22. Inspect the case for any cracks. Look particularly closely at the area where the orifice
housing and the lever support clamp down. Replace the case if any cracks are found.
23. Inspect the sealing surface on the orifice (where the poppet insert seals) for any nicks,
scratches, or corrosion. Corrosion or minor scratches can be polished out using a fine-grit
rubberized polishing stick or a clean new pencil eraser. Do not apply heavy pressure when
rotating the polishing stick. Stop polishing immediately after the corrosion or scratch
disappears. An orifice will not be accepted for warranty replacement simply because it is dirty
or corroded. The technician must clean the orifice sealing surface at every service interval.
24. Blow all dust and debris out of the orifice housing with clean compressed air.
5.3 ASSEMBLY OF SECOND STAGE
1. Install the exhaust valve into the case by inserting the nipples into the small holes from the
outside of the case. Reach inside the case and pull the nipple firmly with the fingers until you
hear or feel it “click”into place. Inspect the exhaust valve to see that it is properly seated.
2. Install the lever support and assembly into the case, setting it firmly between the guide ribs
in the Case.
3. Lubricate and install new o-rings & from the annual service kit onto the orifice . Install
the orifice back into the orifice housing using the fingertip. Use the adjustor knob to turn the
orifice counter-clockwise fully, until it stops.
14
NOTE : Prior to this point, you should have cleaned and inspected all parts, following proper servicing
procedures. Do not continue until this has been done.
NOTE : If only the lever is to be replaced, do not totally remove the screw. You can remove the lever
from under the screw when the screw is almost all the way out.
NOTE : If you use an ultrasonic cleaner to clean the second stage adjustable orifice , use a plastic
container to prevent the orifice from vibrating against other metal parts which could damage the orifice seal.
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14 15 11 12
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4. Screw the orifice housing onto the threads of the lever assembly. Using a 3/4" wrench on
the orifice housing tighten them together snugly (70 in. lbs., 7.8nm).
5. Lubricate and install new o-rings & from the annual service kit onto the orifice housing
Note that the larger of the two o-rings goes on the end of the housing closest to the case.
6. Install the cover onto the case by sliding the retaining loop over the orifice housing. Since
the inner parts of the case have not yet been installed, the cover is rotated on the orifice
housing out of the way at this time.
7. Lightly lubricate the inner bore of the swivel fitting with the recommended grease. Install the
swivel fitting onto the orifice housing.
8. Install the retainer nut onto the orifice housing thread. Tighten the retainer nut snugly.
(70 in. lbs., 7.8 nm)
9. Install the cir-clip onto the orifice.
10. Install the adjusting knob onto the orifice.
11. Install the washer onto the screw . Place a small drop of locking adhesive onto the
threads of the screw, and install it snugly into the orifice using a size 0 square drive or Phillips
screwdriver.
12. If the old o-ring on the adjusting lever was replaced due to wear, lubricate and install a
new one onto the adjusting lever. If the o-ring is not worn, in can be lubricated in place on the
adjusting lever. Install the adjusting lever into the case . Using a small slotted screwdriver,
install the retainer clip onto the adjusting lever in its groove inside the case. Move the
adjusting lever through its full range. Check that the fins & move freely in the mouthtube
area. If they touch the top or bottom of the mouthtube and hang-up, rotate the lever support
slightly until the fins move freely. If the fins do not follow the adjusting lever tip through the
entire stroke, rebend the fins slightly to create the proper tension to keep them against the
lever tip.
THE FOLLOWING STEPS (13-19) ARE INCLUDED HERE FOR CONTINUITY. THEY MUST BE
PERFORMED AFTER THE REGULATOR SECOND STAGE IS ADJUSTED (see Section 5.4, Set-Up of
Second Stage).
13. Install the diaphragm into the case so that it sits evenly on the ledge.
14. Install the retaining ring into the diaphragm recess.
15. Work the cover over the case until it sits properly in its groove in the cover.
15
NOTE : A drop of mild thread loc er, such as Loc tite 242® or equivalent should be applied to the threads
of the lever support to prevent the Orifice Housing from loosening during use.
NOTE : Do not allow lubrication (grease on fingers, silicone overspray, etc.) to get on the case , the
diaphragm , the retaining ring , or the exhaust valve . This may cause these parts to slip or
deteriorate.
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16. Install the exhaust tee onto the case using the two screws .
17. Tighten the exhaust tee screws using a # 10 Torx screw driver just enough to seat them
snugly. There is no reason to turn these screws beyond the first contact point. Do not
overtighten. These screws are threaded into plastic, which will hold well in service but is easily
stripped if overtightened.
18. Install the mouthpiece . Be sure to position the mouthpiece so that the word “Sherwood”is
on the top.
19. Install a new mouthpiece tie . For diver’s comfort, be sure the clamp is on the side, not the
top or bottom.
20. Install the hose into a serviced first stage, and the second stage, tighten snugly.
5.4 SET- UP OF SECOND STAGE
For the following adjustments, remove the cover and diaphragm.
1. Turn the adjuster knob out counter-clockwise all the way.
2. Use a # 10 Torx screwdriver to turn the poppet screw counter-clockwise outward, until the
lever assembly & is just loose enough so that the tip of the lever will move loosely up
and down about 1/16”.
3. Attach the second stage to the overhauled and properly adjusted first stage that it is going to
be used with, mounted on a air tank filled to between 2700 and 3500 psig. Install an
intermediate pressure gauge into one of the low pressure ports.
4. Carefully turn the air on. With the lever slightly loose against the lever support , there
should be no air leaking from the second stage with proper intermediate pressure applied to
the hose. If there is air leaking from anywhere on the second stage, correct the problem before
going further.
5. With the air turned on, use a #10 Torx screwdriver to turn the poppet screw clockwise until
a slight hiss is heard coming from the second stage. Work the lever up and down a few times
to ensure that the slight hiss still exists when the lever is released This adjustment has just
lifted the poppet seat off the orifice seal area. This is the long term storage position (one week
or longer) for the adjustment knob .
6. Turn the knob slowly clockwise. The hissing should stop by the time the knob is turned 1/8
to 1/4 of a turn clockwise. If the hissing does not stop by the time the knob has been turned
1/4 of a rotation clockwise, then inspect the orifice sealing area and seat for damage.
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WARNING
Proper torque for the hose fittings is 40 in. lbs. (4.5 Joules). NEVER tighten the hose
fitting to the first stage with more than 45 in. lbs. (5 Joules) of torque. The inlet hose fit-
ting can be weakened by overtightening. Failure of the fitting could cause air loss result-
ing in death, personal injury or property damage.
NOTE : Depending on the owner’s needs, either the Blizzard, Oasis and Maximus style extended tee for
maximum bubble dispersion, or the Magnum/Brut style shorter tee for minimum weight and drag, can
be installed on any of the three models.
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7. If the hissing has stopped properly, continue turning the knob clockwise until the stop is
felt. Breathe on the regulator. It should breathe fairly hard at this setting, but still deliver a good
air supply.
8. Check the purge button for proper operation.
9. After setting the poppet screw and orifice , the relationship between the diaphragm wear
plate and the tip of the lever must be checked. To do this, install the diaphragm and
retaining ring. The tip of the lever should just barely touch the diaphragm. If when touching the
diaphragm lightly with the finger there seems to be a significant gap between the lever tip and
diaphragm, remove the diaphragm and bend the lever slightly upwards using the fingers. If the
regulator hisses slightly when the air is turned on, but stops hissing when the diaphragm is
removed, then the lever is too high. Use Sherwood’s lever bending tool (p/n 4005-16) to bend
the lever slightly downward as shown in Photo #5. There are two indentations at the proper
lever bend point.
10. Replace the diaphragm and test the gap between the lever and the diaphragm again after each
bending. Lever bending is usually necessary only when a new lever is being installed in the
regulator. If you are re-using the same major parts of the regulator, this measurement will most
likely be correct, and no adjustment will be needed. In fact bending the lever should be avoided
unless necessary to get the tip of the lever in the proper position.
11. Replace the cover .
12. Return to
Section 5.3.13 of this manual to complete assembly of the regulator.
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Photo #5
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