Gasmizer Manual - Submarine Manufacturing and Products Ltd

March 2009
Remedy: Diving may be continued by backing off very slightly on BPR loader in dive
control. Set up to 1 bar below recommended value. Drain umbilical and
water trap at the end of the bell run and check for lose fittings on the
outside of the bell. Ensure that the divers helmet and mask are in good
condition and not leaking water and the oral nasal properly fitted to lower
exhaust connectors. Most importantly, bellman must always drain lower
part of the internal water trap when filled with water.
Symptom: Pressure increase in the system volume tank when make-up regulator is
not flowing.
Cause (A): Diver using standby onboard gas instead of umbilical supply in the bell.
Remedy: Diver put on umbilical supply.
Cause (B): Standby going down as umbilical supply and coming back up the exhaust
hose to the volume tank.
Remedy: Regulate standby gas below make up regulator pressure.
Symptom: Gas escaping from the bell into the exhaust circuit and the bellman has to
blow down regularly to prevent water coming up the bell trunking.
Cause (A): Scrubbing valve 3 open.
Remedy: Close valve 3.
Cause (B): Water trap drain valve 7 open with isolation valve 6 pushed in.
Remedy: Close valve 7.
Cause (C): Leaks at inward relieving valves on umbilical fitting below valve 5.
Remedy: Remove caps and check for gas being sucked into valves. Also check that
relief valves on top of water trap are not relieving inwards by removing the
caps.
Cause (D): Valve 9 opened too far.
Remedy: Set valve 9 as per bell check-off sheet.
Cause (E): O-rings on isolation valve damaged or water trap large O-rings leaking.
Remedy: Replace damaged O-rings.
Cause (F): Hose to helmet not being dived disconnected, and valve 5 knocked open.
Remedy: Close valve.
Symptom: A great deal of gas being used for the dive but the diver assures the
supervisor that he is on closed circuit and losing very few bubbles at this
helmet.
Cause (A): Diver tracking pneumo flow set far too high.
Remedy: Set to correct flow in the bell of 0.4 litres/min. maximum. When the diver
leaves the bell there should be one bubble every 10-20 seconds at the
tracking pneumo end on his umbilical.
Cause (B): Loose fittings on the outside of the bell or the inside of the bell losing gas.
Remedy: Tighten up all fittings.
Chap 8 Page 95 of 168 OM002 Rev 5