Coolant Recovery Tank - Yanmar 6LPA-STP2 Service Manual

COOLING SYSTEM

Coolant Recovery Tank

When the engine is operated, the fresh water
temperature increases and fresh water expands to
increase the freshwater tank pressure. When the
pressure in the freshwater tank exceeds
2
0.9 kgf/cm , 0.09 MPa (12.8 psi), the pressure cap
valve opens to release steam. If this steam is
discharged to the atmosphere, the fresh water is
consumed. In order to prevent the fresh water
consumption, steam is discharged into the coolant
recovery tank. Steam discharged into the coolant
recovery tank condenses in the water, thus
preventing discharge of fresh water to the
atmosphere.
When the engine stops, the fresh water
temperature decreases to drop the pressure in the
freshwater tank. When the pressure in the
freshwater tank drops, the negative pressure valve
of the pressure cap activates to return the water
from the coolant recovery tank to the freshwater
tank. The water level in the coolant recovery tank
rises during the operation (hot state) or lowers
during stopping (cold state) (Figure 7-20).
Figure 7-20
Figure 7-20
1 – Full Mark
2 – Low Mark
7-14
Components Related to Cooling System
Coolant Recovery Tank Installation
1. Check the fresh water level on the coolant
recovery tank (Figure 7-21, (1)) daily. It is not
required to remove the pressure cap.
2. Install the overflow pipe (Figure 7-21, (2)) with
a maximum length of 1000 mm (39.3 in.). Avoid
bending the pipe.
Figure 7-21
( 2 )
( 1 )
3. Check the fresh water level in the coolant
recovery tank after the engine is cooled down.
Replenish fresh water as needed to maintain
the fresh water level between the LOW and
( 1 )
FULL marks.
4. Periodically check the overflow pipe and
mounting plate (Figure 7-21, (3)) for cracks and
replace as needed. Check the pipe for
obstructions and clean as needed. Also, check
for disconnected or loose pipe joints. If the
coolant recovery tank leaks air the coolant
( 2 )
recovery tank will not function correctly.
0005348
© 2007 Yanmar Marine International
Figure 7-21
6LPA Service Manual
( 3 )
0005349