It has two possibilities that whether you want to do do partial blowdown or complete blowdown.
Starting with partial blowdown.
- Ship must not be in port or nearby offshore platforms .
- Feed water pump must be in auto.
- Open ship side valve.
- Open boiler blowdown valve gently.
- Control the blowdown rate using intermediate valve.(while blowdown keep an eye on gauge glass, in my ship we use blowdown for 120 seconds every alternate day) (however the blowdown rate depends on boiler water test report)
- Once blowdown is done close intermediate valve,then boiler blowdown valve.
- Drain the line by opening intermediate valve and then close intermediate valve and ship side valve.
Complete blowdown procedure.(working pressure<7 bar)
- Changeover generator and boiler on diesel.
- After flushing the fuel line with diesel is done,close steam stop valve and shut the boiler.
- Wait for the pressure to drop to 4 bar.
- Changeover feed to manual.
- Once pressure is 4 bar,start blowdown in steps to avoid thermal shock.
- When pressure reaches 1 bar open air vent to prevent vaccum.
What are the causes if gauge glass shows low water level ?
1. One gauge glass defective
2. Boiler tube crack and leaking
3. Feed water regulator jammed
4. Failure of feed water pump (Air in feed water line or pump)
5. Level controller malfunction
6. Steam consumption is too much