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.