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Clarke C18 User Manual

Clarke C18
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36
Clarke cooling loops are FM Approved to meet standard sizing conditions of 50% blocked wye strainers,
100degF (38degC) raw water inlet temperature, 80 psi inlet pressure, and 10 psi available at the engine outlet.
Figure #7-4 shows the standard NFPA 20 cooling loop piping arrangement. The cooling loop consists of an
Automatic flow line with a 12v or 24v solenoid valve (HSC and ES pump applications only) that is energized to
open anytime the engine is called upon to run from either the fire pump controller or from the engine
instrument panel.
NOTE: VT type pump applications do not require a solenoid valve in the Automatic flow line.
NOTE: With the Mechanical Engine and Alarm Control Board, See section 3.5.5, the solenoid valve will open 15
seconds after engine shutdown and will stay open for 60 seconds. This allows for raw water to flow through the
heat exchanger and reduce the heat soak rise caused in the engine.
The second flow line is called the Manual by-pass line and it can be opened at any time if for any reason the
engine shows signs of overheating. Each line has two (quarter turn) shutoff values installed and the normal
position of the shutoff valve is to remain open in the Automatic flow line and remain closed in the Manual by-
pass flow line.
NOTE: Opening both lines to flow is never a problem should there be some concern of engine overheat,
especially if there is an emergency situation. The Manual by-pass line can only be opened by an operator in
the pump room.
The shutoff valves are all identified to show which are Normally Open (Automatic flow line) and which are
Normally Closed (Manual by-pass flow line). The shutoff valves are also used to isolate water pressure in the
event of maintenance to pressure regulators, strainers and solenoid valve. Shut off valves in the Automatic flow
line are provided with lockable handles for cooling loops that have been tested to FM requirements.
In each flow line there is also a pressure regulator. Each pressure regulator protects the downstream piping
from over-pressurization which includes the tube side of the engine shell & tube heat exchanger (and/or CAC)
and to control raw water flow rate. The pressure regulators are set to limit downstream pressure to 60 psi (4
bar). There is a 0-60 psi (0-4 bar) pressure gauge installed at the cooling loop outlet, and prior to the engine
heat exchanger (or CAC).
Wye strainers are used to remove debris from the raw water supply. One strainer is in the Automatic flow line
and the other is in the Manual by-pass flow line.
Note: See section 9.1.11 regarding strainer maintenance.

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Clarke C18 Specifications

General IconGeneral
BrandClarke
ModelC18
CategoryEngine
LanguageEnglish

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