Sherwood Scuba SR2 User manual

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SR2 Service Manual
- First Stage -

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INTRODUCTION
The instructions set forth in this document are intended to guide the experienced scuba equipment repair technician
through the standard service procedure for this regulator.
It is assumed that the technician possesses basic scuba equipment repair training, proper tools and the skill neces-
sary to perform the service. If you have not received regulator service training provided by Sherwood Scuba specif-
ically for this equipment, do not attempt to perform the service described in this document.
Service parts for Sherwood equipment are sold only to Authorized Sherwood Dealers.
Before attempting to perform service read this manual in its entirety. There are warnings and cautions contained in
the manual that may affect your safety or the safety of the regulator user.
If you are uncertain as to whether you are qualified to perform this service contact your regional Sherwood Scuba
Distributor for technical assistance.
USE OF WARNINGS, CAUTIONS AND NOTES
REGISTRATION, INSPECTIONS AND SERVICES ON-LINE REGISTRY.
All Sherwood regulators have to be registered right after purchase, either by the end consumer or the dive center
where the item was acquired. If the dive center is not capable to register the product for the end-consumer at the
time of purchase, the sales associate form the dive center has to strongly encourage the end-consumer to register
the product as soon as possible.
Effective immediately: recording inspections and services is required to ensure the proper continuity of the war-
ranty process. Regardless of location, proper record keeping by the authorized dealer is required right after each
inspection or service is performed.
When the regulator is going to be used for recreational purposes a year or 150 dives after purchase an inspection is
required; a year after such inspection or when the regulator has completed 300 dives a full service is required. Time
frames may be different when the regulators are going to be destined for public service, rental or instructional use.
Please contact your local Sherwood Sales representative for additional information to discuss particular cases and
usage.
WARNING: Indicates a potentially hazardous condition or situation which, if not avoided,
may result in serious injury or death.
CAUTION: Indicates a potentially hazardous condition or situation which, if not avoided,
may result in minor injury. It may also be used to alert against unsafe practices.
NOTE: Indicates an important point or reminder

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Registration, services and inspections most be recorded at our website:
Go to www.sherwoodscuba.com sign in using your dealer credentials, & locate the Product Warranty tab and fol-
low the instructions to record inspections and services:
(ask your sales rep if you have questions regarding on-line event recording).
WHEN TO SERVICE
This regulator should be inspected at least annually. In most cases a simple inspection, and if needed,
minimal adjustment not requiring the replacement of parts will be sufficient for continued use. Guidelines for the
Annual Inspection are included in this manual.
This regulator is designed and tested to perform acceptably under typical recreational diving conditions up to 300
hours of use.
If the regulator has been subjected to more than 300 hours of use, a year has passed since the last inspection or it
has not received the benefit of careful post-dive cleaning and storage in a clean environment, a standard service
overhaul is required.
In any case the regulator should receive a standard service overhaul at least every two years to maintain
optimal performance. The standard service overhaul includes disassembly, cleaning, inspection, replacement of
seals, lubrication, reassembly and adjustments.
Sherwood Scuba offers a standard service kit that contains the parts recommended to be replaced in combination
with the standard service overhaul.

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ANNUAL INSPECTION GUIDELINES
1. Visually inspect the first and second stage for signs of damage or deterioration. Mouthpieces with tears or other
damage should be replaced.
2. Retract hose protectors and inspect the hose over its entire length for signs of damage including blisters, deep
cuts or separation at the crimped fittings. If these signs are present the hose must be replaced and standard
service overhaul is recommended.
3. Insert a soft probe through the exit port of the exhaust cover and lift the Exhaust Valve to inspect it for cuts, tears
or contaminated surfaces. Perform this examination from both sides of the Exhaust Cover to observe the entire
perimeter of the Exhaust Valve. If damage to the Exhaust Valve is found a complete overhaul is recommended.
If the Exhaust Valve or the sealing surfaces on the Housing are contaminated with debris, the Exhaust Cover
must be removed and the surfaces must be cleaned. Instructions for removing and replacing the Exhaust Cover
appear in the Second Stage Service Guide. As a final check of the Exhaust Valve apply a moderate suction
(approximately minus 5 inches of water, moderate inhalation effort) to the second stage mouthpiece with the air
supply closed and the second stage purged. If leakage is detected a complete overhaul is recommended.
4. Inspect the first stage filter for evidence of contamination. Discolored filters indicate previous contact with
contaminated air. If evidence of contamination is present it is recommended that a standard service overhaul be
performed. In addition you should advise the customer that the regulator has been exposed to contamination
and that previously used air cylinders used should be inspected.
5. Install an intermediate pressure gauge into one of the available LP ports.
6. Pressurize the regulator to approximately 500 psi and inspect for leakage. If air leakage through the second
stage is detected, it is possible that the second stage Orifice is not in position to create a seal. Close the valve to
stop the air flow and reopen quickly. This will generate enough sudden pressure to move the Orifice to its
proper position. Note intermediate pressure. It should not be greater than 145 psi. If no leakage is detected
increase pressure to 3000 psi. Again check intermediate pressure. It should not exceed 145 psi. The specified
intermediate pressure for the SR1 & SR2 is 135+/- 10 psi. If intermediate pressure is out of range or leakage is
present a standard service overhaul is recommended.
7. With the second stage Control Knob set at the least sensitive position (rotated fully clockwise) test the purge
function. If there is not a strong surge of air, a standard overhaul is recommended.
8. Gently submerge the entire regulator and look for bubbles that indicate leakage. If leakage is present a standard
service overhaul is recommended.
9. If a test bench is available perform an inhalation test. With the Control Knob in the most sensitive position
(rotated fully counterclockwise) inhalation effort should not be greater than 1.5 inches of water at opening and
less than 4.0 inches of water at 15 SCFM. If there is a slight leakage of air present refer to Adjustments Section
of this manual and adjust as needed. If adjustment fails to stop the leak a standard overhaul is recommended. If
a test bench is not available perform a subjective breathing test. When properly adjusted the regulator should
provide smooth and easy inhalation. If difficulty with inhalation is suspected a standard overhaul is recommended.

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GENERAL COMMENTS
1. Read the entire set of procedures that follows before starting to service. Steps taken out of sequence or without
the knowledge of the proper procedure could damage the regulator or otherwise complicate the service process.
2. Refer to the Illustrated Parts List while performing service. Each part is identified with a reference number the
first time it appears in the text. Parts that are to be replaced with new parts in conjunction with an overhaul have
encircled reference numbers.
3. Do not attempt to reuse parts that are designated for replacement. Retain discarded parts to show to the
customer to illustrate that a full overhaul service has been completed.
4. Work in a clean properly equipped area. Cleanliness is essential for all regulator servicing and is critical for
regulators that will be exposed to enriched air mixtures (Nitrox). Do not attempt to service if all required tools
and a clean work area are not available.
5. Work on one regulator at a time taking care not to mix parts from other regulators. Use only genuine Sherwood
parts. Parts that appear similar may have different features that are not easy to detect and may cause poor
performance.
6. Be careful to protect the finish on all surfaces of the regulator during the service procedure. When holding parts
in a vise use soft or padded jaws to prevent defacing surfaces.
7. O-rings are classified by the service they perform and are identified as either static or dynamic. Dynamic
O-rings are those that are subjected to movement and the effects of friction which tend to shorten the useful life
of the O-ring. Static O-rings are used to create a seal between non-moving parts and are not subject to the
same wearing effects. In general Static O-rings have a longer useful life and their replacement is not required
unless they show signs of deterioration, deformation or brittleness. Careful inspection of these O-rings is manda
tory before they are returned to service.
8. When removing O-rings use a plastic or a soft brass tool to lift the O-ring out of its groove. Do not use
steel or other hard tools that might scratch sealing surfaces.
9. When instructed to use tools such as a hex key or a wrench, follow the standard convention to rotate clockwise
to tighten and counterclockwise to loosen unless otherwise directed.
10. When instructed to tighten a part until snug, it means to apply torque just until the part stops moving freely and
the torque requirement to advance it further rises markedly. When specific torque values are given there is a
necessity to ensure that the part is tightened precissely to retain position and not loosen over time. A torque
wrench must be used every time a torque value is specified; excessive torque may damage parts and require
replacement and parts that are left lose will become unstable potentially leading to a catastrofic failure while un
derwater.
NOTE – Read this section first before attempting to perform service.

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ENRICHED AIR NITROX SERVICE
All SR1 & SR2 components & service kit has been designed and manufactured to allow the use of Enriched Air
Nitrox (EAN) gas with an oxygen component not to exceed 40%.
In order to maintain this option the user must ensure that the regulator is protected from the introduction of
hydrocarbons. The introduction of hydrocarbons into the regulator may increase the risk of fire when used with EAN.
When servicing the regulator, the technician must be aware of this requirement and exercise caution not to
contaminate the regulator with hydrocarbons. This requires a clean workplace, free of oil, grease, debris and other
contaminants. Additionally in order to return the regulator to EAN service, the overhaul procedure must have a
cleaning provision to remove all hydrocarbons before the regulator is reassembled. Do not substitute parts or use
lubricants other than Tribolube 71 or Christo-Lube MCG 111. Silicone lubricants are NOT acceptable and in-
crease the risk of a fire hazard.
FACILITY REQUIREMENTS
The service facility is perhaps the most important asset of any professional dive store. It should be clean, well lighted,
and stocked with a complete inventory of parts and manufacturer’s specialty tools for the products your store sells. As
a minimum requirement, your service facility should be equipped with the following items:
• Ultrasonic Cleaner - Select the right size model that can keep up with the volume of regulators that your
store services. A built-in timer and heater will help control the cleaning time and temperature of the solution,
since most solutions work best when heated.
• Bench Mounted Vise - A vise is sometimes needed to hold the regulator secure – especially when removing
the first stage yoke retainer. Special care must be taken, however, to avoid damage that can result from improper
use of this tool. Be sure to follow the instructions provided in this manual.
• Magnification Lamp - Strong lighting and magnification are essential requirements for performing a
thorough parts inspection - especially when locating the cause of a small leak.
• Quality Wrenches & Sockets - When working with chrome plated brass parts, it is especially critical to use
the correct size wrench and to ensure that it fits properly over the part. The use of an adjustable wrench is very
likely to cause damage to your customer’s regulator, and should be strictly avoided at all times.
• Calibrated Inch-Pound Torque Wrench - it is important to follow the manufacturer’s torque values
whenever they are specified, in order to avoid overtightening or under tightening a part. This is especially
important for smaller parts and fittings, when overtightening can easily damage the part.
• Calibrated Foot-Pound Torque Wrench - Torque wrenches that can be set for both inch-pound and
foot-pound measurements generally tend to be less accurate than wrenches that are designed to measure torque
within a specific range.
• Manufacturer’s Specialty Tools - Specialty Tools are critically important to perform many of the steps during
disassembly and reassembly according to each manufacturer’s procedures. During the mentioned steps where the
procedure clearly indicates the use of a specialty tool, Sherwood Scuba strongly discourages technicians the
use of substitute or “make-shift” tools to perform such steps; expect parts damages if anything but specialty tools
is used. Sherwood specialty tools required to perform service are listed on the following page.
WARNING – The introduction of hydrocarbons, lint, dirt and other contaminants into the areas of
the regulator subjected to high pressures (greater than 500 psi) and EAN mixtures containing more
than 40% oxygen may constitute a fire hazard and may subject the user to serious injury.

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RECOMMENDED TOOLS AND SUPPLIERS
The specialty tools identified below may be purchased from your Sherwood Scuba Distributor. Common tools are
available from several sources.
Common Tools
Open End Wrenches - 9/16”, 5/8”,1/2”
Box End Wrench – 3/4”
Hex Keys 1/4”, 5/32”,1/8”
Small Flat Blade Screw Driver
Padded Pry Bar
Torque Wrenches 25 ft-lb and 60 in-lb
Flashlight
Airgun
1/4” x 6” Plastic Probe
O-ring picks/ small probes, plastic or soft metal
Magnifier
Specialty Tools
SR1 Tool Kit 20-700-100
Includes the following:
HP Seat Retainer Tool 20-621-100
Cover Retainer Tool 20-622-100
Piston Stem O-ring Tool 20-685-400
Poppet/Flange O-ring 20-626-400
Installation Tool
Available specialty tools not included in the kit.
First Stage Spanner 20-600-200
First Stage Handle 20-115-100
Yoke Retainer Socket 20-155-500
Breaker Bar 20-157-500
Snap Ring Pliers 10-101-500
3/8” Drive x 3” Extension 20-156-500

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SECTION
DISASSEMBLY PROCEDURE
1. Record the First Stage and Second Stage serial numbers and an inventory of all attached accessories before
beginning disassembly.
2. Perform an inspection of the regulator in accordance with the Annual Inspection Guidelines. This process will
give the technician a reference point if the after the overhaul the regulator does not perform as expected.
3. Remove all hoses attached to the first stage with a 9/16” open end wrench for the LP Hose and a 5/8” open
end wrench for the HP Hose. BCD Inflator hoses typically require either a 9/16” or 1/2” open end wrench. Tag
all hoses that attach accessories such as gauge consoles to ensure they are returned to the appropriate regulator
port when reassembled.
4. Remove all port plugs (31 & 30) including the port plug in the end of the Port Swivel (3) with a 5/32” hex key.
Remove and inspect O-rings (27 & 35). Replace if signs of damage or deterioration are present, otherwise set
aside for cleaning and reassembly.
If the first stage has a yoke type connector go to steps 5 thorough 8. If the first stage is a DIN
type, go to step 9.
5. With the Body secured in a padded vise, loosen the Yoke Knob (8) to create enough space to fit a 1” Yoke
Retainer Socket (PN 20-155-500) within the Yoke (36) and over the Yoke Retainer (10). Pass the Breaker Bar
(PN 20-157-500) through the Yoke and engage the socket’s square recess. Tighten the Yoke Screw sufficiently
to secure the Breaker Bar and rotate the Breaker Bar counterclockwise to loosen the Yoke Retainer.
NOTE – In order to avoid the risk of damage to the regulator finish during the disassembly process the
preferred method is to secure the first stage body in a bench vise without direct contact between the vise
jaws and the regulator. The First Stage Handle (P/N 20-115-00) or similar device is recommended to
mount the regulator securely without contact between the vise and the regulator body. An alternative
method is to use a woodworking vise with soft jaws to minimize the risk of damage to the regulator finish.
CAUTION – The socket and breaker bar combination provide the best means to prevent damage the
Yoke Retainer during disassembly. DO NOT use an adjustable wrench or open end wrench that does not
properly fit over the flats on the Yoke Retainer. Doing so may result in permanent damage to the Yoke
Retainer or other parts.

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6. Remove the Yoke Retainer (10), Yoke (36), Inlet Protector (13), and Saddle (12).
7. Separate the Yoke Knob from the Yoke and set aside for cleaning.
8. Yoke Retainer Disassembly - While holding the Yoke Retainer securely, use Snap Ring Pliers (PN 10-101-500)
to compress the Retaining Ring (23) and remove it from the groove inside the Yoke Retainer. Remove and dis
card the Filter (32). Remove O-ring (26) & set it aside for cleaning, inspection & reassembly.
9. DIN Connector Disassembly –
a. Insert a 1/4” hex key into the DIN Filter Retainer (43) and rotate it counterclockwise to remove it. Remove
the DIN Hand Wheel (41).
b. Remove the DIN Filter Housing (42) from the Body with a 9/16” open end wrench. Once removed, invert it
to allow filter (32) to slide out of the filter Housing.

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c. If rotating the hex key results in the DIN Filter Housing and DIN Filter Retainer separating from the
Body as a unit, this is acceptable but it will be necessary to separate the parts for reassembly. Place the DIN
Filter Housing in a vise clamping over the flats on the largest diameter on the DIN Filter Housing. This will
stabilize the DIN Filter Housing to allow further rotation of the DIN Filter Retainer to separate the two parts
and provide access to the Filter. Discard the Filter.
d. Remove and discard O-ring (45). Set aside the Din Handwheel (41), O-rings (26), DIN Inlet
Protector (44)
10. Secure the Body (1) to gain clear access to the cap/swivel combo. Fit the First Stage Spanner into
one of the lateral holes in the End Cap (2) and rotate it counterclockwise when viewed from the Port
Swivel.

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11. Use tool 20-115-100 to stabilize the LP Ports. Place 1/4” hex key in the Swivel Retainer (5) and rotate it
counterclockwise to separate the End Cap (2) from the Port Swivel (3). Remove the two O-rings; keep 39 and
discard 28. Remove Washer (19) and Accent Ring (33) and set aside for later reassembly.
12. Remove the Diaphragm Retainer Cap (17) turning it by hand counterclockwise. If necessary the First Stage
Spanner may used to loosen it. Remove the Dry Chamber Diaphragm (18) and Pressure Plate (7). Set it aside
for cleaning, inspection and reassembly.
13. Using a 9/16” x 3/8” socket, secure stainless steel seat retainer tool (20-750-150); the tool mounted in the
socket could be used permanently to facilitate the use of a ratchet or torque wrench.
14. Use tool 20-115-100 on one of the HP Ports of the Body (1) and secure it in the vise. Remove the Seat Retainer
(4) by rotating it counterclockwise with the Seat Retainer Tool and socket. Hold the ratchet’s head with one hand
to prevent tool to slip off.
15. Use shop air pressure (less than 125 PSI) applied at the small orifice located in between the spanner slots on the
Seat Retainer to dislodge the Seat (6). Discard the Seat.

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CAUTION – Be careful not to damage the seating surface of the Piston Stem when performing the next
step. Even the slightest nick or distortion of the seating surface may cause a high pressure leak when
reassembled requiring disassembly of the first stage and replacement of the Piston Stem.
16. Remove the Two- piece Piston Assembly as follows:
a. Carefully insert a 5/32” hex key into the bore of the Piston Stem (16) to engage the hex feature inside the
bore. When properly engaged you should be able to see the Piston Flange (38) rotating while rotating the
hex key.
b. Insert the First Stage Seat Retainer Tool into the slots in the Piston Flange to stabilize it while rotating the
hex key counterclockwise to separate the Piston Flange from the Piston Stem. This will allow the Spring
(24) and the Three-Pin Link (15) to be removed from the Body. Set aside for cleaning and reassembly.
c. Using tool 20-626-400 mount the piston flange to remove inner O-ring (25) as shown. Remove the flange’s
outer o-ring (22) as well. Discard both o-rings & set aside the piston flange for cleaning, inspection and
reassembly.

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d. Push on the threaded end of the Piston Stem through the bore to remove it from the Body. Remove the O-ring
(21) and two back-up rings (20) and discard them. Set aside the Piston Stem and cleaning, inspection and reas
sembly.
e. It is likelly that the Piston Guide (40) will remain inside the body, remove it for better cleaning of the metal
below it.
16. Remove Vent Ring (9) and O-ring (34) from the Body. Set aside for cleaning and reassembly.
17. Using a soft brass pick or equivalent remove and discard O-ring (37) from the Body. Set aside Body for cleaning
inspection and reassembly.

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18. Thermoplastic, silicone rubber, anodized aluminum parts, diaphragms, adjustment knobs, re-useable
o-rings (26, 27, 34, 35 & 39) and thermoplastic housings.
a. Soak in a solution of warm water and ordinary liquid dish detergent. Scrub with a soft nylon bristle brush
to remove deposits.
b. Rinse with fresh water and blow dry with clean low pressure compressed air.
19. Chrome-plated Brass and Stainless Steel parts –
a. When only mild deposits are visible, soak in a solution of warm water and ordinary liquid dish detergent.
Scrub with a soft nylon bristle brush to remove deposits.
b. If warm water soaking & scrubing does not remove mineral deposits, use a commercial grade heated
ultrasonic cleaner. Sherwood Scuba recommends Lawrence-Factor’s LFW (CM-763215-CN) solution
diluted with water (25% LFW/75% water) and a 3-10 min treatment.
Monitor immersed parts for signs of chrome plating peeling off. Do not subject thermoplastic or rubber
parts to ultrasonic cleaning. Link from the product’s website:
http://www.lawrence-factor.com/Agents/Agents.asp?ItemNumber=CM-763215-CN
c. Alternatively, if an ultrasonic cleaner is not available soak parts in mild solution of white vinegar and
water (50%) for about 30-60 minutes. (Monitor immersed parts as chrome plating peeling may occur)
d. Rinse first with freshwater and follow up with a final rinse in deionized (distilled) water. Tap water
typically contains minerals that will leave undesirable residue on the cleaned parts if final rinse is omitted.
21. Hoses –
a. Corrosion or mineral deposits on the metallic fittings on hoses may be cleaned using the procedure
presented above provided that care is taken to just dip only the metal fittings at each the end of the hose
into the cleaning solution. Take care to prevent entrance of the solution into the hose interior.
b. Rinsing should include flushing the interior of the hose with fresh water followed by drying with
compressed air.
GENERAL CLEANING PROCEDURE
SECTION

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General – Inspection and lubrication must be preceded by thorough cleaning to enable adequate exposure of
damaged parts and proper application of lubricant.
Inspection
22. Inspect all O-rings that are intended for reinstallation (26, 27, 34, 35 & 39), for signs of damage such as tears,
cuts, deformation, brittleness or abrasion. If damaged replace.
23. Inspect the first stage Dry Chamber vent hole in the Body. Direct light into the Dry Chamber of the Body and you
should be able to see that the vent hole is clear. If it is not, pass a small pin or wire with a diameter slightly less
than the hole size though the hole to remove any obstructions. Do not reassemble if you are unable to confirm
that the hole is clear.
24. Inspect the sealing edge of the Piston Stem using a magnifier. If there are any nicks, cuts or other deformities at
the sealing edge the first stage may not provide the high pressure seal needed for the regulator to maintain
a stable intermediate pressure. If such damage exists the Piston Stem must be replaced.
25. Inspect O-ring groove on the outer diameter of the Piston Flange (38) and the interior walls of the first stage
End Cap (2) for scratches, gouges or deposits that could interfere with proper air sealing. Parts with defects that
cannot be corrected with cleaning must be replaced.
26. Inspect the sealing surface in the Body that will receive O-rings #s 37 & 21. It must be free of gouges, scratches
and debris.
INSPECTION AND LUBRICATION PROCEDURES
SECTION

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General Ample
27. Inspect the Dry Chamber Diaphragm (18) for signs of damage such as cuts or tears. If damaged replace it.
28. Inspect the Yoke (36) and Yoke Retainger (10) for cracks or distortion. If deformed replace them.
29. Carefully inspect Body (1), Yoke Retainer (10) or Din Filter Housing (42), Port Swivel (3), Swivel Retainer (5)
and first stage diaphragm Retainer Cap (17) for damage to threads. If threads are damaged the affected parts
should be replaced. On all cases where parts with chipped or scratched plating are still functional (altered cos-
metic appearence) will only need to be replaced at the discretion of the owner.
Lubrication
Tribolube 71 is the recommended lubricant for Sherwood regulators. Alternatively Christolube 111 could be
considered as a viable substitute. Silicone lubricant is NOT approved and may present a hazard for use with
Enriched Air Nitrox (EAN).
30. O-ring lubrication
a. General – O-rings in most instances should receive only enough lubricant to ensure they are supple. A light
coating of lubricant should present a surface that glistens but without a defined layer of lubricant visible.
b. Ample – When an ample application of lubricant is specified it generally applies to a dynamic O-ring subject
to considerable motion or environmental conditions where a more generous application of lubricant might be
beneficial. In this situation there should be a light film or layer of lubricant visible.

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31. Install the Vent Ring (9) onto the Body (1) ensuring it’s tapered shape matches the body’s shape.
32. Inspect the body cavity accepting the o-ring that frictions against the HP Seat (37) one more time to be certain
that there are no contaminants present. Apply ample lubricant to the mentioned O-ring and install it into the
Body.
33. Reassemble the Piston Assembly as follows:
a. Install O-ring (22) onto the Piston Flange’s outer groove.
b. To facilitate insertion place the Piston Flange over the O-ring installation Tool (PN# 20-626-400) and install
generaly lubricated O-ring (25) into Piston Flange’s inner channel. Remove installation tool and set aside the
Piston Flange for later assembly.
c. Use 20-685-400 Piston Stem O-ring Tool (cone) to cover the piston stem threaded end. Amply lubricate red
o-ring (21) and slide both the backup rings and the O-ring over the tool to install. The tool will protect the
o-ring’s inner sealing surface from being sliced by the piston stem’s threads. Ensure the correct order of
piston guide, backup rings and o-ring as shown. The two back-up rings must have their cupped surfaces
against the red o-ring. Picture also shows white piston guide (40) used in SR2 only; cone tool should not be
used to install the Piston Guide.
SECTION
REASSEMBLY PROCEDURES

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d. Place the sealing end of the Piston Stem over a 5/32” hex key and use this tool to guide the Piston Stem’s
threaded end through the Body until it is positioned at the opposite side of the Body & ready to receive the
Piston Flange. Generally Lubricate the bottom back up ring and piston guide to facilitate insertion.
Extreme
caution is encouraged while inserting hex tool to prevent damage to Piston Stem’s sharp edge.
e. Install the Three-Pin Link (15) ensuring that the pins align with the holes in the Body until the Three-Pin Link
fully seats inside the Body and moves freely.
f. Insert Spring (24) in Body.
g. Amply lubricate both the Piston Flange outer O-ring (22) and the body’s sealing surface. While the Piston
Stem is secured by the 5/32” hex key go to the other end & start threading the the Piston Flange clockwise
by hand until bottoms, then place 20-750-150 First Stage Seat Retainer Tool into the Piston Flange’s slots
and thighten slightly but only until it is just snug. Only light hand torque is sufficient to avoid thread damage.

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CAUTION – It is imperative that O-ring (37) is amply lubricated to minimize deformation when the HP
seat retainer gets fully torqued over the o-ring, apply additional lubricant if needed.
34. Install general lubricated O-ring (34) taking care to avoid damage to the O-ring as it passes over the threads on
the Body.

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CAUTION – It is absolutely essential for the surface of the seat to be clean and free of any scratches,
distortion or any contaminants to ensure it will seal against the incomming high pressure, failure to
observe this precaution may result in leakage and possible damage to the regulator.
35. Install a new Seat in the Seat Retainer and thread it into the body by hand first. Secure the Body with 1st stage
handle and padded vise. Using the Seat Retainer Tool and a Torque Wrench torque Seat Retainer to 7 ft·lb.
Hold the torque wrench head with one hand to stabilize tool and ensure the Seat Retainer tool’s tips from slip
ping off the HP seat retainer damaging it.
36. Install the Pressure Plate (18) over the thightened HP Seat Retainer and pins from the 3 pin link, these pins
should be visible through the orifices. Install the Dry Chamber Diaphragm into the Retainer Cap and then install
the Retainer Cap onto the Body. Tighten until snug. Alignment of the Sherwood logo is random.
37. Reassemble Port Swivel and End Cap as follows:
a. Install O-rings (39 & 28) onto the Port Swivel (3). Install anti friction Washer (19) into End Cap (2).
b. Install End Cap onto the Port Swivel. Install Swivel Retainer (5) into the Port Swivel and thread it with 1/4”
hex key. Stabilize the Port Swivel using tool 20-115-100 and padded vise. Use torque wrench and torque to
60 in·lb (5 ft·lb), hold torque wrench’s head with one hand while tightening to stabilize tool.
c. Install Accent Ring (33) inside Port Swivel’s outer cavity and ensure is flush against the surface.