Whisper Power M-SC6 Installation Manual page 9

5 SIPHON BREAKER (AIR VENT)
When the point of water injection is below the waterline,
then -when the engine is stopped -there is a risk that the
cooling water may enter the engine as a result of
siphoning. To avoid this happening, the generating set is
designed to accommodate a siphon breaker (air vent). In
the standard delivery the connections are bypassed. Hose
of 19 mm (3/4") inner diameter should be used.
If the generating set cannot be mounted such that the
bottom of the generating set is placed above the waterline,
an air vent must be installed.
Extend the water hose of the by-pass 60 cm above
waterline and install an air vent. Ideally, the air vent should
be mounted above the yacht keel center line (i.e. to
minimize the influence of swaying on the water intake).
The hose of the drain should go downwards. Water must
flow out freely and air has to flow in freely as well.
Fast motorboats will lay deeper when sailing at large
speed and can cause pressure on the waterinlet. This
should be avoided to prevent fleeding the engine.
If the air vent is clogged the water hoses will
not be vented when the generating set has
stopped and water can be forced into the
engine. This leads to immediate engine
problems and eventually severe damage!
DAMAGE CAUSED BY THE INGRESS OF WATER IN
THE ENGINE IS NOT COVERED BY WARRANTEE
EN / M-SC 6/8/10 - 3000RPM / December 2010
On the valve is a little hose to drain a little water that could
be spilled from the valve. This hose should go down and
may not end under water, because it should ventilate air
into the valve to break the siphoning (figure 8).
OPEN
Fig 8: Wrong siphon breaker hose routing
Check the air vent at regular intervals. Open, clean and
lubricate the valve as required.
Fig. 9 Whisper Power siphon breaker
INSTALLATION
OPEN
9