Compressors

Compressor use should be logged in the compressor book, upstairs in clubrooms. If you are using the in-line filter (nitrox blenders / divers only), remember to record this in the compressor log.

Clubrooms electric compressor

Clubrooms electric compressor

You’ll need to fill your own bottles for going diving. To do this, the club has its own compressors. Currently we have an electric Coltri-Sub double compressor used in clubrooms and two portable Bauer petrol-powered compressors. The grey compressor is the older and is known as the ‘Biomar’ compressor. The blue one is referred to as ‘Phil’ by frivolous people. There is no need to copy them.

Electric compressor instructions

  1. Turn on power at wall.
  2. Connect cylinders (up to 4 can be filled at one time).
  3. Open tap No.1 (turn anti-clockwise) – see Fig.1 below.
  4. Close bleed screw No.2 (turn clockwise) – see Fig.1 below.
  5. Ensure that tap No.1 and bleed screw No.2 are closed on any whips you are not using.
  6. Open cylinder pillar valve – see Fig.1 below.
    Air in cylinder will enter compressor and pressure gauges will start to rise.
  7. Start compressor by pressing green button – see Fig.2 below.
    Wait 30 seconds before starting 2nd engine to avoid blowing a fuse.
  8. When cylinder is full, close pillar valve and tap No.1
  9. Open bleed screw No.2 and disconnect cylinder.
  10. If you have finished filling, press and hold the test purge (yellow) buttons to depressurise the compressor.

N.B. Moisture will drain automatically during filling.
You will hear the compressor drain every few minutes. This is normal.

The compressor has been set to auto-shut off when it reaches 250 bar.

Electric compressor use - Fig. 1

Using the electric compressor – Fig 1

Electric compressor use - Fig. 2

Using the electric compressor – Fig 2

Tips for getting a good fill

  • You can have fast or full, but you can’t have both!
  • Cylinders heat up as they fill, and pressure can drop by 30 to 40 bar when they cool down.
  • The faster the compressor, the more the cylinder heats up, and the greater the pressure drop when it cools.
  • Placing the cylinders in a water bath during filling helps keep them cool.
  • Filling more than one cylinder at once means they fill slower and heat up less.
  • If just filling one cylinder, use only a single engine to fill more slowly.
  • If pushed for time, you can leave your cylinder to cool and top it up later.

More Information

Petrol compressor instructions

The portable petrol compressors are normally only used on trips away. Occasionally, though, it may be necessary to use one in College. As the petrol compressors make far more noise than the electric compressor, only use them outside office hours, and not unsociably early or late. Moving the compressor down the alleyway towards the Luce Hall helps minimise inconvenience to residents in the building next to clubrooms.

Pre-use checks

These checks need to be done at least at the start of each trip

  1. Engine oil
    • Unscrew dipstick at engine base.
    • Oil should be halfway up dipstick, fairly thick and should not smell of petrol
    • If oil is low, top up with 10W/40 semi-synthetic engine oil
    • If oil is high, runny and smells of petrol, drain and replace with 10W/40 semi-synthetic engine oil
  2. Compressor oil
    • Check level (red-capped dipstick on grey compressor, round window on blue compressor)
    • If low (below dipstick notch / below halfway down window), top with Bauer compressor oil
    • Do not overfill!
  3. Petrol
    • Check tank for water. If there’s a significant amount:
      • Siphon out petrol and water, and leave to separate
      • Clean out remaining rust / water with a rag
      • Refuel with petrol

Running the compressor

  1. Open the drain taps
  2. Connect a cylinder to the compressor
  3. Turn on the fuel tap
  4. Turn on the ignition switch
  5. Set the throttle to medium / low
  6. Pull start the compressor
  7. Close the drain taps
  8. Bring throttle up to full speed
  9. When compressor is pressurised, open cylinder pillar valve
  10. Bleed all drain taps every 10 minutes or so, depending on humidity

When finished:

  1. Close bottle
  2. Turn off ignition switch
  3. Bleed all drain taps
  4. Purge decanting whip
  5. Shut off fuel tap