Hollis Prism 2 User manual

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This PRISM 2 Service Procedure conveys a list of components and service procedures that reect the
PRISM 2 as it was congured at the me of this wring (9/12/12).
USER SERVICE GUIDE
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CONTENTS
INTRODUCTION (USER LEVEL)
1. TITLE PAGE, CONTENTS, & INTRODUCTION
DEFINITIONS ................................................................................................................................................................................6
MODIFICATION WARNING ..........................................................................................................................................................7
2. GENERAL PROCEDURES
RECOMMENDED CHEMICALS & LUBRICANTS .......................................................................................................................8
OXYGEN USE ...............................................................................................................................................................................8
SAFETY ........................................................................................................................................................................................9
SERVICE SCHEDULE & ASSEMBLIES
1. SERVICE & PARTS REPLACEMENT SCHEDULE
SCHEDULE .................................................................................................................................................................................13
2. PRISM 2 ASSEMBLIES DIAGRAM
DIAGRAM ...................................................................................................................................................................................15
AMBIENT PRESSURE
1. BREATHING LOOP
TOOLS ........................................................................................................................................................................................ 17
TROUBLE SHOOTING ...............................................................................................................................................................18
INITIAL INSPECTION .................................................................................................................................................................18
POSITIVE PRESSURE TEST .....................................................................................................................................................19
DISASSEMBLY PROCEDURE ...................................................................................................................................................20
REASSEMBLY PROCEDURE ....................................................................................................................................................23
POSITIVE PRESSURE TEST (REPEATED) .............................................................................................................................. 26
NEGATIVE PRESSURE TEST ...................................................................................................................................................27
DISASSEMBLE & DISINFECT PARTS ...................................................................................................................................... 28
EXPLODED VIEW DIAGRAMS & PARTS LISTS ...................................................................................................................... 30

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2. DSV (DIVE SURFACE VALVE)
TOOLS ........................................................................................................................................................................................ 35
TROUBLE SHOOTING ...............................................................................................................................................................36
MUSHROOM VALVE CHECKS ..................................................................................................................................................36
DISASSEMBLY PROCEDURE ...................................................................................................................................................37
REASSEMBLY PROCEDURE ....................................................................................................................................................38
EXPLODED VIEW DIAGRAMS & PARTS LISTS ...................................................................................................................... 41
3. SCRUBBER BUCKET & SCRUBBER BASKET
TOOLS ........................................................................................................................................................................................ 44
TROUBLE SHOOTING ...............................................................................................................................................................45
DISASSEMBLY PROCEDURE ...................................................................................................................................................45
REASSEMBLY PROCEDURE ....................................................................................................................................................49
EXPLODED VIEW DIAGRAMS & PARTS LISTS ...................................................................................................................... 52
BATTERIES & OXYGEN SENSORS
1. BATTERY COMPARTMENT
TOOLS ........................................................................................................................................................................................ 55
TROUBLE SHOOTING ...............................................................................................................................................................56
DISASSEMBLY PROCEDURE ...................................................................................................................................................56
REASSEMBLY PROCEDURE ....................................................................................................................................................58
EXPLODED VIEW DIAGRAM & PARTS LIST ........................................................................................................................... 59

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2. OXYGEN SENSORS
TOOLS ........................................................................................................................................................................................ 60
TROUBLE SHOOTING ...............................................................................................................................................................61
DISASSEMBLY PROCEDURE ...................................................................................................................................................62
MILLIVOLT/LINEARITY TEST & CLEANING ............................................................................................................................ 63
REASSEMBLY PROCEDURE ....................................................................................................................................................64
RECOMMENDED SENSORS .....................................................................................................................................................65
CALIBRATION ............................................................................................................................................................................65
EXPLODED VIEW DIAGRAM & PARTS LIST ........................................................................................................................... 67

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© 2002 DESIGN (2012)
COPYRIGHT NOTICE
This service manual is copyrighted, all rights are reserved. This material may not be reproduced, displayed,
modied or distributed without the express prior written permission of the copyright holder. It may not be distrib-
uted through the internet or computer without prior written consent.
PRISM 2 Service Guide, Doc. No. 12-4090 through 12-4127
© 2002 Design, 2012
San Leandro, CA USA 94577
INTRODUCTION
This guide provides procedures for proper "User Level Repairs" of the Hollis PRISM 2 Rebreather at the time of
this writing. "User Level Repairs" are repairs that Hollis has deemed suitable for end users to perform themselves
as needed. These guides do not cover all systems that require maintenance.
It is still necessary to have a Hollis PRISM 2 Service Facility complete a "Full Service" annually to main-
tain safe operation of the unit.
This guide does not replace proper instruction from a PRISM 2 Instructor. Instructions contained within this guide
are only to be performed by persons trained to dive and assemble the PRISM 2. Before service, ensure with Hol-
lis that this is the most current revision of this guide. If you do not completely understand the instructions given
in this manual, lack the correct tools, or lack the appropriate level of mechanical knowledge - have an authorized
Hollis PRISM 2 Service Facility or Hollis Customer Service complete repairs. Your Hollis PRISM 2 Dealer or
PRISM 2 Instructor can personally advise you on this matter. You may prefer to have your local PRISM 2 Service
Center perform all repairs. Hollis has provided these guides simply as a convenience for those individuals with
the desire and aptitude to complete basic repairs themselves.
WARNINGS, CAUTIONS, AND NOTES
Pay attention to the following symbols when they appear throughout this document. They denote important infor-
mation and tips.
WARNINGS: are indicators of important information that if ignored may lead to injury or death.
CAUTIONS: indicate information that will help you avoid product damage, faulty assembly, or unsafe condi-
tions.
NOTES: indicate tips and advice.

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DEFINITIONS
Absorbent: chemical media used to remove CO2 from exhaled gas
ADV: automatic diluent valve
Bailout: redundant gas supply system
BOV: bail out valve
Breakthrough: where absorbent scrubber fails, no longer removing CO2 at an adequate rate
Breathing Loop: parts of the rebreather that breathing gas circulates within
Diluent: a gas used for breathing volume and to reduce the fraction of oxygen in the Breathing Loop
DSV: dive surface valve
FO2: fraction of oxygen
HP: high pressure
IP: intermediate pressure
LP: low pressure
Negative Pressure Check: a test placing the Breathing Loop under a vacuum condition to check for leaks
OC: open circuit
OPV: over-pressure valve
PO2: partial pressure of oxygen
Positive Pressure Check: a test that looks for leaks in the Breathing Loop when pressurized
QD: quick disconnect
WOB: work of breathing

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PRISM 2 MODIFICATION
WARNING
- This Service Guide is not an instructional manual for operation of the
PRISM 2. This guide only provides instructions on repairing the unit. No
person should breathe from, or attempt to use in any way, a Hollis Prism
2 rebreather, or any component part thereof, without rst completing an
appropriate Hollis Certied user-training course.
- DO NOT modify or change the Breathing Loop components with any after-
market parts. Doing so could dangerously effect the breathing dynamics
of the system and lead to serious injury or death.
- ONLY USE Hollis brand Oxygen Sensors.
- Ensure any BCD used with the unit provides adequate lift capacity
- If a Hollis alternate inator regulator is removed or not installed, an ad-
equate Bailout Gas Supply System must be used.
- DO NOT replace the rst stage regulators with anything other than Hollis
PRISM Regulators. Doing so could impair the function of the Oxygen
Solenoid.
- Modications could void the warranty. See www.HollisGear.com for exclu-
sions.

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PRISM 2 GENERAL PROCEDURES (USER LEVEL)
RECOMMENDED CHEMICALS & LUBRICANTS
Lubrication: Tribolube 71® or CHRISTO-LUBE® MCG 111
CAUTION: Although equivalent Halocarbon Based Lubricants could be used, they may not provide the
same level of Operational Performance.
NOTE: DOW CORNING® 7 silicone may be substituted for all parts EXCEPT those used on Oxygen
Valves, Regulators, and Oxygen Solenoid Assembly Components.
Sanitizing (internal Breathing Loop parts): Steramine™ solution
Cleaning (Internal plastic parts): Crystal Simple Green® solution or mild dish washing liquid
Cleaning (external plastic parts): Crystal Simple Green® solution or mild dish washing liquid
Cleaning (external metal parts): White Vinegar
Cleaning (electrical contacts): DeoxIT® Gold GN5
CAUTION: The electrical connectors have thin precious metal plating. DO NOT scrape corrosion from
contacts with a hard sharp object. DO NOT use abrasives, petroleum distillates, silicone based cleaners,
erasers, combust able chemicals, or any other harsh cleaners. Hollis recommends the use of DeoxIT
Gold® GN5 for cleaning the electrical contacts.
OXYGEN USE
WARNING:
The Hollis PRISM 2 oxygen critical components are prepared for Oxygen Service when shipped from the
factory. If Hollis PRISM OXYGEN Regulators, Oxygen Valves, or the Solenoid are subsequently used with
equipment, or connected to an Air supply system, that is not rated for Oxygen Service, it cannot sub-
sequently be used with Nitrox breathing gases containing more than 40% oxygen by volume unless it
is again prepared for Oxygen Service by a Qualied Hollis Dealer Facility who is certied in and follows
Oxygen Service Procedures.
This text ONLY covers disassembly, reassembly, and tuning procedures. Oxygen Service Procedures
are beyond the scope of this guide and are not covered within this text. DO NOT attempt to service any
Regulator, Valve, or Solenoid.

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SAFETY
WARNING:
The CO₂ absorbent material used in the Scrubber is caustic alkaline material. Take steps to protect your-
self and your working environment from the effects of airborne dusting of absorbent, eye, and skin con-
tact. Good protection would include gloves, eye protection, and a dust mask. See Material Safety Data
Sheets for the absorbent material for further safety recommendations before working with the Scrubber
Bucket Assembly.
PRIOR TO PERFORMING SERVICE:
EXTERNAL INSPECTION
• Visually inspect the Regulator First Stage Cone Filters for any visible residue present.
• Closely examine all metal parts for any signs of external corrosion.
• If the metal parts have a chrome nish, check closely for any aking or chipping. DO NOT clean any Parts found
to be aking or chipping chrome in an ultrasonic cleaner.
PRIOR TO DISASSEMBLY
• Ensure that you have the latest revision of this Service Guide and all Hollis Service Updates. Contact Hollis
Customer Service to conrm.
• Be certain to perform the Initial Inspection and Troubleshooting Procedures of each section of this Service Pro-
cedure Guide prior to beginning any Section's Disassembly. Doing so will provide clues as to which Internal Parts
may be worn.
• Review the complete Disassembly and Reassembly sections provided in this Service Procedure Guide for the
specic Assemblies being serviced.
• Ensure that you are equipped with all of the Tools and Parts needed. DO NOT attempt to perform the Service if
not equipped with the proper Tools and Parts.
• Perform the outlined steps in the order given, without exception. The Reassembly Procedures have been
outlined with the assumption that you rst followed the Disassembly Procedures as outlined.
• Before reusing or scrapping any parts during service, refer to the Parts Replacement Schedule and Letter Codes
(a, b, c) that follow the Exploded View Diagram Numbers. DO NOT allow old parts to be reused.
• O-rings are classied as being either dynamic or static. Dynamic O-rings are mounted directly on a moving Part,
or they create a Seal against a moving Part. Static O-rings create a Seal between two non-moving Parts. Since
Dynamic O-rings sustain friction and movement, they are to be discarded and replaced during every Service,
regardless of age or appearance. Static O-rings are less subject to wear and after passing close Inspection may
sometimes be reused, although this is not necessarily recommended. Always follow the Service & Parts Replace-
ment Schedule Outlined in the following section.

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• To help avoid any confusion during Disassembly, those parts that are not to be replaced automatically should be
Inspected after Disassembly is completed. They should be laid out in the order they are removed, and compared
with identical new parts to better discern their condition before Reassembly is performed.
• O-rings should be Inspected using a magnier to ensure they are supple, well rounded, and completely free of
any scoring or corrosion that would impair proper sealing. Replace any O-rings in questionable condition.
CLEANING AND LUBRICATION:
TOOLS AND CLEANING SUPPLIES
• Tools to be used must be clean and free of contaminates such as dirt, dust, silicone grease, and oil.
• A supply of warm to hot clean fresh water will be needed for rinsing.
• For blow drying parts and components, a clean (oil free) low pressure air supply is to be used.
DISASSEMBLY
• Again, prior to beginning Disassembly perform the Inspection and Troubleshooting Procedures at the beginning
of each of this Guide's sections.
• Disassemble the different PRISM 2 components in accordance with the disassembly section provided in this
Service Procedure Guide.
CLEANING TIPS
CAUTION: DO NOT use a metal wire brush.
WARNING: If salt or grit is found on any O-rings, discard them and replace with new ones. DO NOT at-
tempt to reuse them.
• Prior to Cleaning, carefully remove any existing thread locking residue from the Threads using a brass or plastic
dental instrument.
• During Cleaning, use special care not to damage Components such as those with delicate Seating Surfaces.
CLEANING - GENERAL
Plastic or Rubber Parts
• Reusable soft and hard Parts, such as regulator Spacers and Protector Caps may be soaked and cleaned in a
solution of warm water mixed with mild dish soap.
• To scrub away deposits, use only a soft nylon toothbrush.

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Metal Parts, General
• General Metal parts may be soaked and cleaned in a solution of Crystal Simple Green®, mild dish washing
liquid, or white vinegar (for corrosion).
• To scrub away deposits, use only a soft nylon toothbrush.
WARNING: DO NOT introduce any cleaning agents into the Breathing Loop that may off gas or be un-
healthy to breathe. Please see all Safety Data for any cleaning agent, and take all precautions to thor-
oughly rinse any cleaner residues away.
FINAL INSPECTION
• Examine all O-ring sealing surfaces for scratches, burs, gouges, and deformation. Repair as needed.
Sealing Surface Inspection Tips
• Use a bright inspection light and magnifying glass to aid seeing damage and defects in the dark colored plastic
(Fig. 1).
• Follow the O-ring grooves with a toothpick, end of a paintbrush handle, or other such device that can not scratch
the plastic. This will help you to identify defects you can not see.
PRE-ASSEMBLY
• To ensure that the Parts do not become contaminated, assemble the components immediately after completion of
Cleaning and Final Inspection.
• Ensure that all Replacement Parts used are those specied in the Service Procedure(s) for use with the PRISM 2.
Lubrication
• Lubricate O-rings and other components as described in the Reassembly Procedure sections of this Service Guide.
• Dress the O-rings with a very light lm of Lubricant.
• Avoid applying excessive amounts of Lubricant, as this will collect contaminants such as sand.
• Use only Hollis approved lubricants. They are listed at the beginning of this section.
Fig. 1

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ASSEMBLY
• Assemble the PRISM 2 Components according to the Reassembly Procedures described in each section of this
Service Procedure Guide. Refer to the PRISM 2 User Manual for instructions on how to assemble all Compo-
nents together into a complete and working PRISM 2 unit.
• Perform any and all Testing as described in each section of this Service Guide.

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1. PRISM 2 SERVICE &
PARTS REPLACEMENT SCHEDULE
S = SERVICE, R = REPLACE
PART AS NEEDED 12 MONTHS 36 MONTHS 5 YEARS
Head to Inhalation Counterlung hose S/R R
Head to counterlung hose connector
O-rings
S/R R
Inhalation Counterlung S/R
ADV S/R R
Inhalation mushroom valve S/R R
Inhalation mushroom valve seat S/R R
Inhalation Hose S/R R
DSV O-rings (3) S/R R
Exhalation mushroom valve S/R R
Exhalation mushroom valve seat S/R R
Exhalation hose S/R R
Exhalation counterlung S/R
Manual O2 Addition Valve S/R R
OPV R R
Head to Enhalation Counterlung hose S/R R
Exhaust Plenum O-Ring (Not Gasket) S/R R
Red CO₂ Seal S/R R
Scrubber basket S/R
Basket Spring S/R
O2 cell holders S/R R
O2 cell wiring harness S/R R
Battery Cap sealing O-rings (2) S/R R
Battery Cap Latches R
Battery Cap Pressure Relief Valve R R
Bucket sealing O-Rings S/R R
Oeteker Clamps R R
Bucket Latches R
Oxygen First Stage S S
Diluent First Stage S S
O2 LP Hoses & QD S/R S R
O2 HP Hose & QD S/R S R
O2 Gas restrictors S/R S

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PART AS NEEDED 12 MONTHS 36 MONTHS 5 YEARS
Diluent LP Hoses & QD S/R S R
Diluent HP Hose S/R R
O2 Pressure gauge S/R S
Diluent Pressure gauge S/R S
Oxygen Solenoid S/R S R

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9
8
10
3
2
4
14
13
6
5
12
1
11
7
13
16
17
19
18
15
2. PRISM 2 ASSEMBLIES
DIAGRAM

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DIA. P/N DESCRIPTION NOTES
1 28674 HEAD ASSEMBLY Doc. 12-4093, Technician only
2 27755 SCRUBBER BASKET & CAP Doc. 12-4094
3 27985 BUCKET ASSEMBLY Doc. 12-4094
4 28224 NUT BAR
5 28680 MOUNTING TUBE
6 28217 MOUNTING POST
7 28681 COVER ASSY.
8 29229 H FRAME ASSY.
9 29228 SCREW, NYLON
10 27270 REG. ASSY. OXYGEN Doc. 12-4096, Technician only
11 27271 REG. ASSY., DILUENT Doc. 12-4096, Technician only
12 28834 WASHER
13 28832 SCREW
14 24819 LOCK NUT
15 28764 COUNTERLUNG, INHALATION Doc. 12-4094
16 28729 COUNTERLUNG, EXHALATION Doc. 12-4094
17 29225 HOSE ASSY. EXHALE Doc. 12-4094
18 29226 HOSE ASSY. INHALE Doc. 12-4094
19 27759 DIVE SURFACE VALVE ASSY. Doc. 12-4094
PRISM 2 ASSEMBLIES
DIAGRAM PARTS LIST

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Tools Required
1. BREATHING LOOP
Specialty Tools
P/N 220.9102 Tribolube 71
P/N 220.9101 Christo-Lube MCG 111
P/N TBD Oetiker clamp pliers
P/N TBD STERAMINE™ sanitizer
P/N TBD Thin Nut Wrench
P/N TBD SI-TECH® attachment tool
P/N TBD O-ring removal tool
(plastic)
Standard Tools
magnifying lens
inspection light
pure breathing gas supply

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TROUBLESHOOTING
The Breathing Loop (DSV/BOV, Breathing Hoses, Coun-
ter Lungs; Scrubber Assembly) of the PRISM 2 is sensi-
tive to wear and tear (Fig. 1). It should be thoroughly
inspected during any service. The key failure to be
looking for is a leak or a worn component that is about
to fail. The Breathing Loop must be able to maintain a
positive and a negative pressure. Throughout inspec-
tion be vigilant to identify bad O-rings, damaged mating
surfaces, holes, sticking valves, damaged hoses, and
damaged hose clamps.
Be on the lookout for modications to the Breathing
Loop that are not factory approved. These may include
any number of things. For example a diver may have
changed the Breathing Hoses to a longer hose for com-
fort reasons. This may seem benign but modications
that have not been tested and approved may increase
Work Of Breathing (WOB) to an unsafe level or cause
other safety risks. The Breathing Loop has been heavily
tested by Hollis for many conditions of use. Technicians
are not equipped nor authorized to perform the proper
testing to evaluate the suitability of after market or
modication parts. The technician MUST assemble the
PRISM 2 to current factory standards and conguration.
If there is any question as to the authenticity/approved
nature of a component, contact Hollis Customer Service
for further advice.
INITIAL INSPECTION
1. Inspect the BREATHING HOSES (13, 21, 31, 45)
for any holes, wear, age, or cracking. Discard if found.
Stretch the hose slightly and inspect the rubber material.
If you can see separation or light cracking in the rubber,
discard DO NOT attempt to reuse.
2. Inspect all ttings for integrity. Discard if cracked or
damaged. Ensure all ttings are secure.
NOTE: All Breathing Loop Fittings tighten clock-
wise.
3. Inspect the COUNTERLUNGS (30, 44) for tears or
abnormal wear. Shake the COUNTERLUNGS (30, 44)
to ensure no foreign objects have entered the COUN-
TERLUNGS (30, 44) during storage or transport. Clean
or replace COUNTERLUNGS (30, 44) as necessary.
Fig. 1

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4. Inspect the DRAIN VALVES (43, 54) at the bottom
of each COUNTERLUNG (30, 44) for proper opera-
tion. Loosen the locking collar clockwise, and actuate
the DRAIN VALVES (43, 54) by depressing the nipple
inward toward the body of the valve (Fig. 2). It should
pop back out when you let go of the valve. If it does not,
it must be replaced. If in good condition, re-tighten the
locking collar counterclockwise.
5. Check the ADV/MANUAL DILUENT ADDITION
VALVE (52) for tightness by gripping the COUNTER-
LUNG (44) Flange with one hand and turning the ADV
(52) Fitting Nut clockwise until snug, DO NOT over-
tighten (Fig. 3). Visually inspect the ADV (52) for cracks
or breakage, anything that may cause a leak. See ADV/
Manual Diluent Addition Valve section for further service
procedures for this item.
6. Check the MANUAL OXYGEN ADDITION VALVE
(38) for tightness by gripping the COUNTERLUNG (30)
Flange with one hand and turning the OXYGEN ADDI-
TION VALVE (38) Fitting Nut clockwise until snug, DO
NOT overtighten (Fig. 4). Visually inspect the valve for
cracks or breakage, anything that may cause a leak.
See Manual Oxygen Addition Valve section for further
service procedures for this item.
7. Rotate the OVER-PRESSURE VALVE (OPV) (40)
open and closed. You should feel a slight ratcheting
as you twist. If the motion is not smooth The valve will
need to be replaced. For now rotate the OPV (40) body
clockwise until it is fully closed in preparation for a Posi-
tive Pressure Test (Fig. 5).
8. Inspect the DSV/BOV (1). Open and close the valve
to ensure smooth operation. Any scraping sounds
or stiffness during barrel movement means the Valve
requires service. See the DSV and BOV sections for
further component service instructions.
9. Close DSV/BOV (1) for Positive Pressure Test.
POSITIVE PRESSURE TEST
1. Ensure all Breathing Loop components are connect-
ed and properly tightened as described above.
2. Rotate the OVER-PRESSURE VALVE (OPV) (40)
body clockwise until it is fully closed.
3. Ensure the DSV/BOV (1) is closed.
Fig. 2
Fig. 3
Fig. 4
Fig. 5

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4. Using a regulator rst stage and LP QD hose at-
tached to the ADV/MANUAL DILUENT VALVE (52),
ll the COUNTERLUNGS (30, 44) with pure breathing
gas, until gas vents from the OVER-PRESSURE VALVE
(OPV) (40). The COUNTERLUNGS (30, 44) should be
full and rm to the touch.
5. Listen for any air escaping. Also look for any dea-
tion of the COUNTERLUNGS (30, 44).
6. Let the unit stand for 5 minutes inated. Look again
for any deation or loss of COUNTERLUNG (30, 44)
fullness.
7. Any escaping air or deation means the breathing
loop has failed The Positive Pressure Test.
8. If the unit passes step 7, open the DSV/BOV (1).
There should be a rush of air released. If that is not the
case, the Breathing Loop has lost gas and failed the test.
NOTE: Be aware that if the ambient temperature
and introduced gas temperature are not matched
the unit may falsely fail the Positive Pressure
Test. Avoid this by allowing the unit and breath-
ing gas supply tanks to reach room temperature
before performing the test.
9. If the Breathing Loop has failed this test, repair/re-
place any leaking component found during this test. Re-
peat the test as necessary to nd the source of failure.
NOTE: If the Breathing Loop has failed the Positive
Pressure Test and the source of failure is known,
continue the service with disassembly. Include the
needed repair/service before reassembly. The unit
will need to be Positive Pressure tested again and
pass before being returned to the customer. This
is to ensure repairs have xed the issue and no
other leaks were hidden by the initial leak.
DISASSEMBLY
1. If not already done, disconnect LP QD Hoses from
MANUAL ADDITION VALVES (38, 52).
2. Pull the Primary HUD Display off of the DSV/BOV (1)
(Fig. 6). Set it aside carefully. Keep it out of the way so
it is not damaged. Fig. 6