Service and Repair Manual
Contents
1. washer 14 followed by the main spring pad 15 and held in place by screwing main spring housing 20 tightly into place 5 Place mainspring 18 so it engages main spring pad 15 and screw adjustment cap 21 tghtly over main spring 18 Do not over tighten at this time End of adjustment cap 21 should not screw below level of main spring housing 20 Adjustments will be made later 6 Reverse position again and install bearing washer 1400 over hp housing place yoke 9201 into position and secure by tightening yoke retainer 2287 screw yoke screw 9019 in place HOSE amp MOUTHPIECE ASSEMBLY NOTE This procedure is not necessary for yearly maintenance check one way operation and smooth flow of valves wash in warm soapy water and reassemble to regulator If valves found to be sticky or defective remove and replace using the following guidelines WARNING Because of the likelihood of bacterial build up within the hose mouthpiece assembly it is required to frequently disinfect by removing hose mouthpiece assembly from regulator and submerging hose mouthpiece assembly in weak beach and water solution follow with thorough fresh water rinse Complete disassembly is not required for disinfecting procedure MOUTHPIECE DI SASSEMBLY 1 Slide back rubber sleeves 120 exposing retainer bands 118 unscrew bolts 111 from retaining cylindrical nut 1016 remove bands 2 Remove hoses 200 3 Remove mouthpiece v2. Nemrod Snark Silver Nemrod USA Service and Repair Manual SNARK 111 SILVER 2 HOSE REGULATOR page 1 Nemrod Snark Silver OVERVI EW The 2 hose regulator represents the earliest designs in pressure reduction and air delivery systems in the evolution of the Self Contained Underwater Breathing Apparatus SCUBA Both first and second stages are set together in a compact housing connected to the tank valve The regulator obtains it s name from the configuration it s large inhalation and exhaust hoses This particular design offers a more diffused exhalation to the rear of the diver increasing the field of view and reducing noise level created by exhaled bubbles The 2 hose regulator has also proven itself as a reliable ice diving regulator due to the warm exhaled air maintaining the working mechanism above the freezing point All these features have maintained the popularity of this regulator amongst u w photographs commercial and military divers around the world Due to it s similarity in breathing function with the Re breather the old 2 hose is again sought after as an efficient and economical training device The Nemrod Snark is the only 2 hose regulator X still production with full factory support page 2 Nemrod Snark Silver FIRST STAGE DESCRIPTION Before the development of the single hose regulator both first and second stages were located in the housing Th
3. P increased at a constant rate of 1 50 1 psi increase for every 50 psi drop of tank pressure page 8 Nemrod Snark Silver Safety valve release pressure to be set at 210 psi 14 38 bar Set Intermediate Pressure with tank pressure at 2 500 psi 171 23 bar Tank Pressure Intermediate Pressure 3 000 psi 120 psi 205 5 bar 8 2 bar 2 500 psi 130 psi 171 23 bar 8 9 bar 2 000 psi 140 psi 137 bar 9 58 bar 1 500 psi 150 psi 102 73 bar 10 27 bar 1 000 psi 160 psi 68 5 bar 10 95 bar 500 psi 170 psi 34 24 bar 11 64 bar 300 psi 175 psi 20 54 bar 12 bar Connect hose assembly Test for proper breathing Turn off air and depressurise Place dust cap in place Inhale an mouthpiece no air should be drawn this tests for possible air leaks an hose assembly check valves and regulator body Service is now complete page 9 Nemrod Snark Silver 86 2633 5G 2999 Sa j E A x 1 nh 2968 150 j 13 14 15 18 Q y ie x 29 20 24 5252 2997 745 11692 ot 8031 ib SNARK III SILVER 1 E Sa bp 14095 page 10 Wa uo LNO ay Jq9ry NI ry Sd OIZ paag ISA SET dI Isd 000 dH AAAS HI ORAVNS JOHAN 2 D x c o 5 Z page 11
4. alve support 122 from inside mouthpiece 4 Remove valve assembly 123 check and replace if necessary check valves 106 REPLACEMENT PARTS The following components are required to be replaced yearly High pressure diaphragm 12 High pressure seat 2997 low pressure seat 2985 filter 114 safety valve o ring 95 Cotter pins 75 Rubber gasket 13 Low pressure seat bushing o ring 8443 Main body o ring 81 If housing removed OONOAARWND gt gt page 6 Nemrod Snark Silver Components to be inspected and replaced if found defective 1 Main diaphragm 85 2 Exhaust valve 86 3 Mouthpiece valves 106 4 Hoses 200 5 Any screw showing extensive wear or damage to treads 6 Any O ring showing excessive wear or deformity SECOND STAGE ASSEMBLY 1 Drop seat 2985 note that this is an upstream poppet with stem down into place in housing next place spring 2987 into place replace o ring 8443 and cap with bushing 10769 leave port plug off as this will be used to connect Ip hose for Intermediate Pressure gauge connection 2 Flip regulator and screw into place the lp seat guide bushing 2986 careful not to bend seat stem 3 On poppet lever 88 screw set screw 73 and set retaining lock nut 74 an top of lever NOTE U channel of poppet lever 88 faces towards regulator body 4 Place poppet lever 88 an central guide hinge an regulato
5. e first stage offers the same generic function as all un balanced diaphragm regulators The h p diaphragm holds the upstream h p seat in the open position while at rest High pressure air enters the h p chamber and flows past the h p seat and through the h p orifice or the volcano as it s often called and into the intermediate pressure chamber The pressure builds against the upstream low pressure seat until reaching a set pressure of 140 psi where it overrides the main spring pressure and collapses the diaphragm causing the h p seat to seal against the orifice and stop airflow As the diver inhales the large low pressure diaphragm collapses an the lever assembly This pushes the up stream l p seat up and away from the seating surface and allows the air flow to the diver As the air pressure in the intermediate chamber drops the main spring pushes against the h p diaphragm which raises the h p seat and full air flow is now established On any upstream second stage regulator it is imperative to have a pressure release valve This allows the second stage to remain operational in the event of a catastrophic h p seat failure which would have the tendency to press shut the seat with the increasing air pressure On the Snark III the over pressure relief valve is found an the back just above the yoke assembly and is set to free flow at a pressure of 210 psi DISASSEMBLY HOSE ASSEMBLY REMOVAL 1 Remove hose assembly by fir
6. e spring 99 and safety valve plunger 98 4 Unscrew safety valve body 2597 remove from regulator body 3879 washer 94 0 95 and washer 96 CLEANING The regulator is now ready for cleaning The use of an ultrasonic cleaner and weak acid solution is recommended In the event that cleaning solutions are not available the universal cleaning agent is 50 white vinegar and water followed by thorough fresh water rinse LUBRICATION The use of silicone based lubricants is acceptable and compatible with this regulator NOTE Please be aware that the O rings are metric and buna They are not interchangeable with US standard ASSEMBLY 1 If complete disassembly was made align main body 3879 with regulator housing 2668 careful not to pinch 0 81 Tighten by using bolts 83 FIRST STAGE ASSEMBLY 1 Place regulator body 3879 flat an bench with hp orifice facing up drop in new hp seat 2997 followed by spring 25 support crown 24 filter 114 perforated disc 28 and held in place by circlip 29 2 Flip assembly and insert push pin 2988 and place pin pad 150 over the pin head At this point push in an pad with fingers to insure proper travel and spring pressure 3 Place hp diaphragm 12 into pace over pin pad 150 Make sure diaphragm reaches the bottom all the way around page 5 Nemrod Snark Silver 4 Place rubber gasket 13 over hp diaphragm 12 place plastic
7. i at 2 500 psi of tank pressure Note the chart an the last page 1 Set regulator an test bench or pressurised scuba tank to 2 500 psi 2 Connect low pressure hose from port behind Ip seat to Intermediate Pressure Gauge If not using a test bench connect the submersible pressure gauge to the regulator at the H P port 3 Open valve slowly tighten clockwise main spring adjustment cap 21 until Intermediate pressure reaches 210 psi purge often to set proper pressure NOTE If safety bleed valve starts free flowing below 210 psi of IP tighten down adjustment screw 100 to prevent free flow 4 Adjust safety valve to begin to free flow at a pressure of 210 psi of intermediate pressure 5 Reduce intermediate pressure by backing off counter clockwise the main spring adjustment cap 21 and set I P to 130 psi 6 Reduce the tank pressure and watch for Intermediate Pressure increase as pressure drops This may be accomplished by adjusting inlet pressures an a test bench or turning off tank valve and taking little breaths from the regulator keep an eye an the H P gauge to indicate tank pressure Setting exact pressures is very difficult in an unbalanced regulator with a small main spring so a of 10 psi 68 bar after the regulator is assembled will be acceptable Because the Snark is an unbalanced upstream diaphragm regulator the Intermediate Pressure IP will increase as supply pressure decreases Curiously the I
8. r body 3879 and slide into place hinge pin 71 securing it with cotter pin 75 remember to spread ends 5 Place diaphragm lever 2993 channel away from regulator body into regulator housing hinge an 2668 slide hinge pin 184 and secure with cotter pin 75 spread ends to secure SAFETY VALVE ASSEMBLY WARNING The threaded opening for the safety valve is not compatible with US Ip hoses Do not use this orifice as a Ip port SAFETY VALVE ASSEMBLY MUST BE IN PLACE AND IN PROPER WORKING ORDER WITH A MAXIMUM BLEED OFF PRESSURE OF 210 PSI 1 Place small washer 94 into safety valve orifice an main body 3879 above housing 2 Place o ring 95 an top of washer 94 3 Place large washer 96 an top of o ring 95 4 Screw valve body 2597 tightly into place 5 Insert into valve body 2597 safety valve plug 98 then spring 99 6 Screw into place adjustment screw 100 but do not tighten at this time page 7 Nemrod Snark Silver SETTING PROPER PRESSURE LEVELS It is important to understand that in the case of unbalanced upstream diaphragm regulator as the tank pressure drops the intermediate pressure will increase Therefore the regulator will undergo various Intermediate Pressure levels during use The use of conventional downstream regulators as octopus may free flow at lower tank pressures The Snark Ill 2 hose regulator is designed to function with an intermediate pressure of 130 ps
9. remove Pin from h p end and insert a thin metal drift through h p orifice and push out h p diaphragm 12 remove Pin pad 150 CAUTION use extreme caution to insure orifice brass volcano is not damaged never allow any metal tool to come in contact with the rim of the brass volcano orifice The use of a pencil eraser is an ideal way to polish and inspect the orifice SECOND STAGE DISASSEMBLY 1 Remove l p plug 14095 remove bushing 10769 remove Spring 2987 remove l p seat 2985 2 Reverse housing position and remove pin lever 88 by removing cotter pin 75 slide out Pin 71 remove lever remove set screw 73 and retaining locknut 74 from lever 3 Remove Diaphragm lever 2993 in same fashion remove Cotter pin 75 slide out lever pin 184 remove lever 4 Remove l p guide bushing 2986 from regulator body 3879 5 Disassembly of regulator housing 2668 from regulator body 3879 is not necessary unless excessive corrosion or deteriorated conditions exist This is accomplished by unscrewing bolts 83 and replacing O ring 81 page 4 Nemrod Snark Silver SAFETY VALVE REMOVAL Because the Snark Ill is of upstream second stage design it is imperative that the safety valve be in proper operation and bleed setting this prevents regulator lock up in case of a h p seat failure 1 Unscrew safety valve plug 2598 2 Unscrew and remove pressure release adjustment screw 100 3 Remov
10. st removing the rubber sleeves 121 Nuts 1016 Band screws 111 and Bands 112 2 Unscrew Clamp ring 2633 take off box top 2999 and remove Diaphragm 85 NOTE The use of plastic wire ties of sufficient size and strength may be substituted for metal bands at regulator connection only two an each side are recommended CAUTION do not use wire ties at mouthpiece connection page 3 Nemrod Snark Silver FIRST STAGE DISASSEMBLY 1 Inspect Exhaust valve 86 if found in deteriorated condition remove by pulling If in good condition leave in place 2 Using a 12 adjustable crescent remove Yoke retainer 2287 remove yoke 9201 remove plastic bearing washer 1400 3 Using circlip tool remove circlip 29 caution the high pressure assembly is under spring tension h p assembly is now ready to be removed Filter disc 28 Filter 114 Bushing 24 Spring 25 and high pressure seat 2997 4 Turn housing over unscrew Main spring adjustment nut 21 remove Main spring 18 unscrew Main spring housing 20 remove Spring pad 15 remove Plastic trust washer 14 remove Rubber trust washer 13 CAUTION do not remove h p diaphragm 12 from this side as it will scratch housing 5 Turn housing over and using soft wood plastic drift or pencil eraser push an Pin 2988 using your index finger nail remove h p diaphragm 12 If Pin 2988 has been damaged or excessive corrosion exists
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