Starting:

• When the telegraph is moved to the desired command, e.g., Dead Slow Ahead from STOP, a solenoid valve in the control system is energized.
• This admits control air to the Ahead switch, which directs air to pneumatic cylinders fitted on each fuel pump. These cylinders shift the fuel pump roller to the “ahead firing” position.
• Control air is also supplied to the starting air distributor, preparing it for the ahead start sequence.
• After these actions, the Ahead switch supplies air to the interlock system, releasing it.
• The control air then opens the Main Automatic Valve (Auto v/v), admitting ~30 bar starting air into the engine via the starting air distributor.
• The starting air is admitted to cylinders as per the firing sequence, and the engine begins to rotate.
• Once sufficient starting RPM is achieved, starting air is cut off, and fuel admission begins, completing the starting sequence.

Stopping:

• The telegraph is moved to STOP.
• This energizes another solenoid valve, which supplies air to the puncture valves of the fuel pumps, cutting off fuel injection, and the engine stops.

Reversing:

• After the engine has completely stopped, the telegraph is moved to Dead Slow Astern.
• A solenoid valve supplies control air to the Astern switch and simultaneously vents the Ahead switch.
• The Astern switch directs control air to the fuel pump pneumatic cylinders, shifting the rollers to the astern firing position, and also supplies air to the starting air distributor.
• The air distributor now operates according to the astern firing order.
• After the interlocks are released, the engine is started in the astern direction using the same process as ahead, but with the astern firing sequence.

(i) Engine fails to turn on air

Causes:

• Low pressure in starting air receiver.
• Valve on starting air receiver closed.
• Valve to starting air distributor closed.
• No pressure in control air system.
• Main starting air valve stuck/locked.
• Turning gear interlock engaged.
• Pistons in starting air distributor sticking.

Remedies:

• Start compressors and pressurize the air bottles.
• Open the air receiver valve.
• Open the valve to the distributor.
• Check control air pressure and open supply if closed.
• Lift the locking plate to working position.
• Disengage turning gear.
• Lubricate pistons, free them, and overhaul the starting air distributor.

(ii) Engine turns on air but fails to fire on fuel

Causes:

• Puncture valves not deactivated.
• Engine shut-down system tripped.
• Sluggishness in manoeuvring gear.
• Fault in governor.
• Fault in fuel system.

Remedies:

• Identify and correct the puncture valve cause.
• Check pressures and temperatures, reset shut-down.
• Lubricate and free the manoeuvring gear.
• Attempt starting from local control, bypassing governor if required.
• Check fuel pressure and temperature.
• Drain fuel for sludge/water contamination.

(iii) Engine fails to reverse

Causes:

• Reversing solenoid valve not receiving voltage.
• Control air signal not reaching engine due to blockage or defective valve.

Remedies:

• Check electrical wiring and control circuits.
• Inspect system by removing the tappet pipe; locate and clear blockages or replace defective valves.