Uwatec SCUBAPRO D400 2nd STAGE Manual

D400 1/1
MAINTENANCE PROCEDURE FOR D 400 2nd STAGE

D400 2/2
MAINTENANCE PROCEDURE FOR D 400 2nd STAGE
WARNING: this maintenance procedure is only for appointed Scubapro technicians that
followed a complete course on equipment repair and in no case can replace a technical
repair course delivered by an appointed SCUBAPRO/ UWATEC appointed staff.
DISASSEMBLY
Tools needed:
1. Universal tool P/N 43.040.000
2. O ring extractor P/N 43.300.107
3. Small pair of pliers
4. 3/32” ball Allen key
5. Small screwdriver
6. 3 mm Allen key
7. 5 mm socket wrench
1. Do not immediately remove the inter stage pressure hose.
2. Position the 2nd stage in the middle of the chest by holding the regulator by the hose with the
left hand. Place the strongest finger of the right hand inside the exhaust deflector and pull it out.
3. Now remove the inter stage pressure hose with the universal tool. Remove also the o ring with
the extractor.
4. Remove the diaphragm cover, the washer and unhook the diaphragm from the lever.
5. With the universal tool, unscrew the cap. Remove the o ring with the extractor.
6. With the 3/32” ball Allen key, partially unscrew the lever adjustment screw and remove the
lever.
7. With one finger push on the lever adjustment screw to remove the assembled poppet housing.
8. Depending on the version, remove the spring adjustment screw with the 3 mm Allen key or the
small screw driver. Remove the spring pad, the spring and the poppet.
9. Hold the central part of the shaft of the poppet assembly with the pair of pliers and unscrew the
5 mm nut with the socket spanner.
10. Remove the poppet cap, the o ring and the seat from the shaft.
11. With the o ring extractor remove the o ring P/N 01.050.323 from the groove on the shaft.
12. Remove the flow control clip from the aspirator.
13. Hold the bottom part of the housing and place one finger inside the aspirator and tilt the
assembly to disassemble the 2 parts. Take care not to touch the sharp edge of the orifice with a
nail.
14. If before the maintenance the regulator did not leak, we then do not advise to remove the
orifice. If removed, it should then be systematically replaced as the 2 tabs break during removal.
15. If confirmed by the inspection, the orifice needs replacement, break with the screw driver the 2
retaining tabs of the orifice through the air feeding holes.

D400 3/3
16. Use the o ring extractor to remove the orifice and the 2 o rings P/N 01.050.360.
17. Remove the 2 o rings P/N 01.050.147 from the housing with the extractor.
18. We do not advise removing the inlet tube and the dive / pre dive selector. If the selector is
hard to move, partially unscrew the retaining screw through the mouthpiece tube and place some
silicone grease under the selector, screw back the retaining screw and move it up and down
several times.
19. Remove the exhaust valve from the diaphragm.
WARNING: It is not advisable to remove the lever linkage and the exhaust retainer from the
diaphragm.
PARTS CLEANING
WARNING: Refer to cleaning procedure
ASSEMBLY
1. After careful inspection of the cleaned parts and the static o rings that do not need to be
changed, prepare all the parts needed to be changed at every annual service.
a. P/N 11.114.012 the poppet assembly or
° P/N 11.015.015 the seat
° P/N 01.050.323 the poppet o ring
b. P/N 01.050.132 the hose o ring
c. P/N 11.011.120 the adjustment screw
2. Place the exhaust valve on the diaphragm.
3. Assemble the o ring P/N 01.050.132 on the inter stage pressure hose and lightly lubricate.
4. If the poppet assembly has been taken apart, place the o ring P/N 01.050.323 in the groove.
Place the seat taking care to place the smooth surface facing the o ring groove. Assemble the o
ring P/N 01.050.363 on top of the seat, then place the seat retainer and the nut. Hold the middle
part of the shaft of the poppet with the small pair of pliers and tighten the nut with the 5 mm socket
wrench. Do not over tighten. Use a minute drop of thread sealant on the threads of the shaft to
prevent accidental unscrewing of the nut.
5. If the orifice has been removed from the housing, assemble the 2 o rings P/N 01.050.360 in
the grooves and slightly lubricate. Align the 2 locking tabs with the air inlet holes. Thrust down with
extreme care the orifice until the 2 locking tabs take their position in the inlet holes. Do not use
any tool for this operation. Do not allow a nail to come in contact with the sharp edge when
pushing the orifice.
6. Align the tab of the aspirator with the cavity in the housing and firmly push.
7. Place the flow control clip so that the adjustment notches matches the built in nipple. Rotate to
obtain the biggest surface area of air passage. Rotating this clip to partially obstruct the air
passage can drastically reduce the flow characteristics of the regulator.
8. Place the 2 o rings P/N 01.050.147 in the groove of the housing and lightly lubricate.

D400 4/4
9. Assemble the lever in any position in it’s groove and partially screw the lever adjustment
screw with the 3/32” Allen key.
10. Slightly lubricate the poppet o ring and carefully insert it into the orifice.
11. Keep the poppet in contact with the orifice by slightly pushing it down with one finger. With the
3/32” Allen key, catch up the play of the lever until there is no play.
12. Place the spring on the poppet then the friction pad. This friction pad has been designed to be
used 2 ways. A, To decompress the spring: insert the nipple side of the friction pad inside the
spring. B, To compress the spring, place the nipple side in contact with the adjustment screw. As a
general rule, the friction pad should be placed to obtain the lightest spring possible (configuration
A) If during adjustment it is necessary to increase the spring compression, then configuration B will
be used.
13. Screw the spring adjustment screw, depending of the configuration, with the 5 mm Allen key
or with the screwdriver until it is flush with the aspirator. Do not over tighten to create a cavity in
the aspirator.
14. Position the Dive / Pre Dive selector on Dive.
15. Insert the complete poppet and housing assembly by firmly pushing inside the 2nd stage
housing until the 2 o rings take their position. Pay special attention to place the air outlet facing the
mouthpiece tube.
16. The lever is not symmetrical and will not be in the axis of the poppet housing. It is extremely
important to position the lever as follows: when the complete poppet housing is inserted,
the lever should not stick out of the diaphragm level. If it is so, slightly unscrew the lever
adjustment screw with the 3/32” Allen key and remove the lever to insert it the opposite way.
Catch up the play with the Allen key. You will notice that without play, the lever is now inside 2nd
stage housing.
THE 2ND STAGE IS NOW READY FOR ADJUSTMENT
ADJUSTMENT
WARNING: DO NOT ATTEMPT TO ADJUST A 2ND STAGE IF THE INTERSTAGE PRESSURE
IS NOT CORRECTLY ADJUSTED.
1. With the 3/32” Allen key slightly unscrew the lever adjustment screw to obtain a total play
of 4 to 5 mm at the tip of the lever.
2. Place the 1st stage on a full tank, assemble the inter stage pressure hose on the 2nd stage.
3. Hold with one finger the poppet housing in position and open slowly the tank valve. You
can come across 2 cases: either the 2nd stage does not leak or the 2nd stage leaks.
4. If there is no leak, and that the spring adjustment screw is flush with the aspirator (as
indicated in paragraph 13), cycle the regulator a minimum of 20 times to stabilise the parts. If there
is still no leak, adjust the lever adjustment screw to obtain a total play of 3 mm at the tip of the
lever.
5. If the 2nd stage leaks, proceed as follows: With the 5 mm Allen key or with the screwdriver,
screw (clockwise) the spring adjustment screw by ¼ turn. Each time the spring compression is

D400 5/5
changed, it is extremely important to cycle the regulator a few times. As soon as the 2nd stage
stops leaking, screw the adjustment screw ¼ turn more for stability. Now adjust the lever play with
the Allen key to obtain a total play of 3 mm at the tip of the lever.
6. If the spring adjustment screw is completely screwed down and the 2nd stage still leaks,
close the tank valve, purge the regulator, unscrew the spring compression adjustment screw and
reverse the friction disk to place the nipple in contact with the adjustment screw ( refer to
paragraph 12 B). Reassemble according to paragraph 6. If the leak does not stop, disassemble
the spring adjustment screw and change the poppet assembly and start again the complete
adjustment procedure. If still unsuccessful with several new poppet assemblies, change the orifice
(see paragraph 5 for assembly) and start again the complete adjustment procedure.
7. Place the diaphragm as follows: Hook the lever into the lever linkage of the diaphragm. On
the outer periphery of the diaphragm there are 4 injection moulding points, 2 of which are aligned
with the lever linkage. To obtain the best performance, the lever should be at right angle to the
lever linkage. We suggest aligning the 2 mentioned injection points with the parting line of the 2nd
stage housing. Lift the exhaust with the screwdriver to confirm.
8. Place the washer on the diaphragm then tighten moderately the diaphragm cover.
9. Place back the rubber cover.
10. Assemble the o ring P/N 01.050.177 on the cap and moderately tighten with the universal
tool.