Procedure to take indicator diagram:
- Wear proper PPE, especially high-temperature gloves and eye protection
- Take the reading of all the relevant engine parameters
- Ensure the ship, and its engine is running at a constant speed in open sea
- Ensure the weather is calm
- Check whether the spring fitted on the indicator instrument will meet the peak pressure to be expected (max. pressure of Engine)
- Stretch diagram paper firmly over the drum.
- Use correct tool to open the indicator cock valve
- Before taking diagram, open indicator cock, two or three firing strokes, to blow out soot and combustion residues in the cock.
- After drawing atmospheric pressure line, hook the cord to indicator drive, open indicator cock, and take power diagram and shut the cock.
- Remove hook, turn the drum by hand to a place clear from the power diagram, took compression pressure line with fuel cut-off.
- Having taken indicator diagrams from all cylinders, open the indicator instrument and clean all parts especially the piston, thoroughly. After cleaning, apply high temperature grease into the surface of all parts.
Note: Do not allow the indicator instrument to become overheated by too many firing strokes, as it will affect the instrument accuracy.