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Raw Water Circuit
The raw water flow is created by a belt-driven, positive displacement. neoprene impeller pump. The pump
draws raw water directly from the ocean through the sea cock and raw water strainer and passes the water
to the heat exchanger's raw water inlet. The raw water passes through the heat exchanger's tubes, from
around which the fresh water coolant mixture circulates. Heat from the fresh water system is absorbed and
then is discharged from the cooling system overboard through the water-injected wet exhaust system.
Raw Water Pump
The
raw
water pump is a self-priming, belt-driven rotary pump with a non-ferrous housing and a neoprene
impeller. The impeller has flexible vanes which wipe against a curved cam plate within the impeller housing,
producing the pumping action. On no account should this pump be run dry. There should always be a
spare impeller and impeller cover gasket on board (an impeller kit).
NOTE: Impeller failures resulting from a loss of raw water coolant are not warrantable failures.
Self priming occurs when the engine mounted pump is close to or below the water line of the
vessel.
Zinc Anodes
A zinc anode, or pencil, is located in the raw water cooling circuit within the heat exchanger. The purpose
of the zinc anooe is to sacrifice itself
to
electrolysis action taking place in the raw water cooling circuit, thereby
reducing the effects of electrolysis on other components
of
the system. The condition of the zinc anode
should
be
checked monthly and the anode cleaned or replaced, as required. Spare anodes should be carried
on board.
NOTE: Electrolysis action is the result
of
each particular installation and/or vessel location;
not that of the generator. Generators do not produce electrolysis.
If the zinc pencil needs replacement,
hold the hex boss into which the
zinc pencil is threaded with a
wrench while loosening the anode
with another wrench. This prevents
the hex boss from possibly tearing off
the exchanger shell. After removing
the zinc, note the condition
of it.
If the
zinc is in poor condition, there are
probably a lot of zinc flakes within the
exchanger. Remove the end of the
heat exchanger and clean the inside
of all zinc debris. Always have a
spare heat exchanger end gasket in
case the present one becomes
damaged when removing the end
cover. Replace the gasket (refer to
your engine model's heat exchanger
end gasket part number), cover, and
install a new zinc pencil.
NEW
ANODE
45
REPLACE
REPLACE
CLEAH
OR
REPLACE
Westerbeke Generators
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