RDG603A73 - Issue 3
Page 35 of 96
sealed container, such as bottle due to the risk of back siphoning. After fitting, run
the engine and check the unions for leaks. Check again after 5 running hours.
3. The siphon break is equally suitable for use with a marine toilet inlet.
4.
The ½” unit may also be used with 5/8” systems. The ¾” and 1” units may only be
used with the correct hose.
•
Siphon Breaker Maintenance
1. On commercial vessels achieving in excess of 150 engine hours per year, the
unit should have the small valve removed from the top and this should be
thoroughly washed in warm soapy water to remove salt encrustation.
2. On a pleasure vessel this should be done twice a year.
3. On reassembly the engine should be run and the unit checked for leaks. The
hose junctions should also be checked for leaks as part of the daily inspection
procedure for sea cocks, water pipes, oil levels, etc.
19. Hydraulic Drive Transmissions
If an engine is to have a hydraulic drive transmission attached to it instead of a conventional
marine gearbox, a number of points must be observed.
•
Bobtail engines (i.e. Engines supplied without a marine gearbox), normally do not have
a gearbox oil cooler fitted. However if a cooler is supplied, this will only be suitable to
cool a conventional marine gearbox.
•
Hydraulic drive transmissions generate far more heat than a conventional marine
gearbox. Therefore the size of the oil cooler installed must be calculated by the
hydraulic drive transmission supplier. This is to ensure it has sufficient cooling capacity
and is sized appropriately taking into account:
•
Maximum engine power.
•
High ambient summer air temperature.
•
Summer River/Canal/Sea temperature.
•
No additional restriction to engine coolant flow is present.
Hydraulic oil coolers should be installed in the seawater cooling system after
the engine and before the water cooled exhaust injection elbow. They must not be
installed before the engine. Coolers that are installed before the engine will invalidate
the engine warranty.
