Westerbeke 65B-FOUR Instalační manuál stáhnout pdf (Strana 22)

COOLING

SYSTEM

RAW

WATER

COOLING

CIRCUIT

The raw water flow

created by a positive displacement

impeller pump. This pump draws water directly from the

ocean, lake, or river through a hose to the water strainer. The

raw water passes from the strainer through the heat

exchanger (through the heat exchanger tubes) where it cools

the engine' circulating fresh water coolant. The raw water is

then discharged into the water injected exhaust elbow, mix-

ing with and cooling the exhaust gasses. This mixture

exhaust gas and raw water is pushed overboard.

Raw

Water

Pump

The raw water pump is a self-priming, 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 as water acts as a

lubricant for the impeller. There should always be a spare

impeller and impeller cover gasket aboard (an impeller kit).

Raw water pump impeller failures occur when lubricant (raw

water) is not present during engine operation. Such failures

are not warrantable, and operators are cautioned to make sure

raw water flow

present at start-up.

NOTE:

Should a failure occur with the pumps internal parts

(seals

and

bearings), it may be more cost efficient to

purchase a new pump

and

rebuild the original pump as

a spare.

lnspe~ting/Changing

the

Raw

Water

Pump

Impeller

Close the raw water intake valve. Remove the pump cover

and, with the proper size impeller tool, carefully pry the

impeller out

the pump (the impeller can be pried out using

a pair

screwdrivers

an impeller puller is unavailable. Take

care not to tear the impeller). Install the new impeller and

gasket. Move the blades to conform to the curved cam plate

and push the impeller into the pumps housing. When

assembling, apply a thin coating

lubricant to the impeller

and gasket. Open the raw water intake valve. ·

Run the

!;:ngine

and check for leaks around the pump. Also

check for water discharge at the stern tube. Absence

w~ter

flow indicates the pump has not primed itself properly.

NOTE:

Never allow the pump to run

dry.

Even a short period

dry running may destroy the impeller.

RAW

WATER

PUMP

PN52650

INSPECTION:

CHECK

THE

BASE

EACH

BLADE

BENDING

VIGOROUSLY.

REPLACE

THE

IMPELLER

THERE

ARE

ANY

CRACKS.

ANODE

NOT

USE

SEALANT

··~

Heat

Exchanger

!(\~

,~·

/ /

/.DRAIN

CLEAN

AND

REUSE

ZINC

ANODES

The heat exchanger is a copper tube which encloses a num-

ber

small copper tubes. Raw water is pumped through the

small copper tubes and the freshwater coolant from the

engine

circulated around the copper tubes. The raw water

removes heat from the freshwater coolant.

Zinc

Anode

A zinc anode, or pencil, is located in the raw water cooling

circuit within the heat exchanger. The purpose

the zinc

anode is to sacrifice itself to electrolysis action taking place

the raw water cooling circuit, thereby reducing the effects

electrolysis on other components

tlie system. The con-

dition

the zinc anode should be checked monthly and the

anode cleaned

replaced as required. Spare anodes should

be carried on board.

NOTE:

Electrolysis action is the result

each particular

installation and

vessel location;

not

that

the generator.

the zinc pencil needs replacement, hold the hex boss into

which the zinc pencil

threaded with a wrench while loos-

ening the anode with another wrench. This prevents the hex

boss from possibly tearing off the exchanger shell. After

removing the zinc, note the condition

it. If the zinc is

poor condition, there are probably a lot

zinc flakes within

the exchanger. Remove the end

the heat exchanger and

clean the inside

all zinc debris. Always have a spare heat

exch:mger end gasket

case the present one becomes dam-

aged when removing the end cover. Replace the gasket (refer

to your engine model's heat exchanger end gasket part num-

ber), o-ring, cover, and install a new zinc pencil.

Heat

Exchanger

Service

After approximately 1000 hours

operation, remove, clean

and pressure test the engine's heat exchanger. (A local auto-

motive radiator shop should

able to clean and test the heat

:·

::exchanger.)

NOTE:

Operating in silty and/or tropical waters may require

that a heat exchanger cleaning be performed more often than

every

1000 hours.

Engines

& Generators

1 2 ... 17 18 19 20 21 22 23 24 25 26 27 ... 63 64

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