14
Impulse Second Stage Service & Repair Manual
© 1997 U.S. Divers Co., Inc.
Table 1
Troubleshooting Guide
Impulse Second-Stage
SYMPTOM
POSSIBLE CAUSE
TREATMENT
NOTE:
Test with second stage
adjustment knob turned in
clockwise between
1/2 - 3/4 t
urn
CAUTION:
Recommended treatments which require disassembly of the regulator
must be performed during a complete overhaul, according to the prescribed proce-
dures for scheduled, annual service. Do not attempt to perform partial service.
Leakage or freeflow from
1. High first-stage intermediate pressure.
1. Refer to first-stage Troubleshoot-
second stage
(should be 140
±
5 psi)
ing Guide.
2. LP seat(27) damaged or worn.
2. Replace Poppet/ LP seat Assy.
3. Crown(21) incorrectly adjusted,
3. Reset crown and perform Final
lever(26) set too high.
Tuning & Testing procedures.
4. Crown(21) sealing surface damaged.
4. Replace crown.
5. Poppet spring(28) damaged.
5. Replace poppet spring.
Low purge or excessive work
1. Low intermediate pressure.
1. Refer to first-stage Troubleshoot-
of breathing (full cylinder)
(should be 140
±
5 psi)
ing Guide.
2. Lever(26) not properly engaged with
2. Disassemble and inspect condi
Poppet/ LP Seat Assy(27).
tion of Poppet/ LP Seat Assy.
3. Crown(21) incorrectly adjusted,
3. Reset crown and perform Final
lever(26) set too low.
Tuning & Testing procedures.
4. Intermediate pressure hose(8)
4. Clean or replace hose.
clogged or obstructed.
5. Deflector clip(25) installed incorrectly.
5. Remove clip and reinstall.
External air leakage
1. Intermediate pressure hose loose.
1. Tighten to 40 inch-lbs at female
(Immersion Test)
second-stage fitting.
2. Crown O-ring(20) damaged.
2. Disassemble and replace O-ring.
3. Box bottom(6) damaged.
3. Disassemble and replace box
bottom.
Water entering second-stage
1. Hole in mouthpiece(16).
1. Replace mouthpiece.
2. Demand diaphragm(5) damaged.
2. Replace demand diaphragm.
3. Exhaust diaphragm(19) damaged.
3. Replace exhaust diaphragm(s).
4. Vane Adjustment Switch O-ring(13)
4. Disassemble and replace O-ring.
dirty, damaged, or worn.
5. Diaphragm improperly seated
5. Disassemble and properly re-
between box bottom(6) and
assemble. (Check for distortion.)
purge cover(2).
6. Box bottom(6) damaged.
6. Disassemble and replace box
(Check exhaust valve sealing surface.)
bottom.
7. Valve body O-ring(22) damaged.
7. Disassemble and replace O-ring.
8. Spacer bushing(12) worn or damaged.
8. Disassemble and replace spacer
bushing.
