Scubapro MK 25 1st Stage Maintenance Procedure

Important Information for Technicians

This maintenance procedure is intended exclusively for appointed Scubapro technicians who have completed a full equipment repair course. It does not replace formal technical training. Always use a torque wrench where specified to prevent permanent damage to components.

Tools Required

Ensure the following tools are available before starting:

• Universal tool (P/N 43.040.000)
• Socket (P/N 43.191.107) and Socket extension (P/N 43.300.009)
• Field handle tool (P/N 43.300.127)
• O-ring extractor (P/N 43.300.107)
• Filter retainer mounting tool (P/N 43.026.101)
• Bushing assembly tool (P/N 43.300.226)
• Torque wrench and Adjustable spanner
• Interstage pressure gauge or 2nd stage adjustment tool (P/N 41.043.000)
• Screwdriver, 7/32" Allen extension/key, and 22 mm socket

Disassembly

Follow these steps to disassemble the 1st stage:

1. Unscrew all hoses and remove plugs from the 1st stage using the universal tool. Inspect O-rings.
2. Remove the inlet protector and rubber bumper.
3. Use the field handle tool in the HP port to stabilize the body.
4. For INT versions: Remove yoke screw, yoke retainer, filter clip, filter, and O-ring.
5. For DIN versions: Remove tank O-ring, filter retainer, spring, filter, and DIN knob retainer.
6. Unscrew the cap with the multifunction tool. Remove piston, spring, and nylon washers.
7. Unscrew the seat retainer with an adjustable spanner. Remove the friction disc and interstage pressure adjustment screw.
8. Push out the seat and remove the spring. Remove O-rings and super glide bushings using the O-ring extractor.
9. Unscrew the swivel retainer and remove the O-ring and nylon washer.

Assembly

Prepare all parts, including new O-rings and filters, before assembly:

1. INT Version: Install filter, retaining clip, and O-ring. Tighten yoke retainer to 30 Nm.
2. DIN Version: Install O-ring, filter, and DIN knob retainer. Tighten to 30 Nm. Install conical filter and spring.
3. Piston Preparation: Grease the piston, fit T.I.S. bushings and O-rings.
4. Swivel Assembly: Grease the swivel O-ring and anti-friction washer. Tighten swivel retainer to 5 Nm.
5. Piston Installation: Grease piston O-rings and insert into the cap.
6. Seat Installation: Place the HP seat into the body, ensuring the cavity faces the piston knife edge.
7. Final Assembly: Screw the seat retainer to 17 Nm. Reassemble plugs and hoses (4-5 Nm).

Adjustment Phase

Adjustment requires a supply pressure of 200, 230, or 300 bars.

• Connect the 1st stage to a full tank and attach a precise interstage pressure gauge.
• Cycle the regulator 10 times by purging the 2nd stage.
• Check the interstage pressure:
  • 9-10 bars: Correct adjustment.
  • Lower than 9 bars: Unscrew the adjustment screw (1/4 turn increments).
  • Higher than 10 bars: Screw in the adjustment screw (1/4 turn increments).
• Do not pile more than 3 washers (P/N 01.060.219) under the spring if pressure remains low.