38
Figure #19
3.4.7.3 Setting Raw Water Flow Rate
The proper amount of raw water flow thru the
engine is of the utmost importance, and the
pressure gauge value does little to indicate if there
is sufficient flow. When the engine is exercised
weekly, the amount of raw water flow exiting the
engine should always be checked to verify it does
not appear to have diminished.
During initial commissioning of the engine, it is
important to correctly set the raw flow rate going thru
the cooling loop. Each Clarke engine model has an
Installation and Operation (I&O) Datasheet that
provides basic operating conditions of the engine and
most values are given based upon engine speed. You
will find this datasheet in the documentation bag that
is shipped with the engine for your specific Clarke
model. This datasheet must be available during
commissioning to set the proper minimum raw water
flow. With the fire pump flowing 150% of rated
flow, and the Automatic flow line open; verify
sufficient raw water flow rate is achieved and that the
reading of the cooling loop pressure gauge does not
exceed 60 psi (4 bar). You will need to capture the
flow for a specific amount of time coming out of the
heat exchanger and going to a floor drain to establish
a reasonably accurate flow rate value. Using a
container or bucket of known volume, record the time
required to fill the container and compare to the gpm
or L/min value provided on the I&O datasheet. THIS
IS CRITICAL FOR PROPER ENGINE COOLING
AT MAXIMUM PUMP LOAD!!
If proper cooling water flow rate is established then
no fire pump controller alarm will be triggered to
indicate clogged raw water strainer (low raw water
flow).
After verifying raw water flow rate in the Automatic
flowline, open the Manual by-pass line shut-off
valves, and then close the Automatic flowline shut-
off valves and repeat the above process to verify the
flowrate going thru the Manual by-pass line. Note,
with Automatic flowline closed the controller low
raw water flow alarm may be present, this is normal.
Once this is completed; close the Manual by-pass
shut-off valves and open the Automatic flowline
shut-off valves to restore conditions back to normal.
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