DDFP SERIES ENGINES FOR FIRE PUMP APPLICATIONS MP-4. Manual - part 9

DDFP

SECTION 3.4

Page 28

COOLANT PUMP

The engine water pump is a centrifugal impeller type pump.

It is gear dri ven on the I-71, V-71 and V-92 Series engines

and belt driven on the I-53 Series engines.  The rebuildable

pump utilizes a shaft and sealed bearing assembly. The V-71

and      V-92 incorporate an oil seal and tw o splash lubricat-

ed ball type bearings. Each pump also included a w

ater

pump seal weep hole. Should a coolant leak occur at this

location, the pump seal must be replaced. Contact your local

DDC Distrib utor/Dealer for assistance. Should a replace-

ment pump be required for repair , use only the e xact same

type of pump.

THERMOSTAT

Each pump engine is equipped with a temperature control-

ling thermostat(s). Normal operating ranges will vary due to

engine horsepower and operating speed.  The thermostat(s)

are located at the front of the c

ylinder heads. Refer to

Section 5 for specif ic operating temperatures for each

engine.

ENGINE COOLANT HEATER

Fire pump engines must be able to assume full load imme-

diately when used for emergency service. NFPA-20 specifi-

cations require an engine coolant heater Figure 6, Page 29,

to maintain a minimum temperature of 120° F

. (49° C).

Maintaining this temperature assists  the engine to start eas-

ily and produce rated horsepo wer immediately . F or f ire

pump units operation in cold climates optional oil heaters

are a vailable to k eep the engines lubricating oil at a safe

temperature for emer gency start purposes. If pump room

temperatures drop belo w 50° F (10° C),

oil heaters are

required.

On the initial installation of each f ire pump engine, it is the

responsibility of the installing contractor to wire the heater

to the pump room  AC circuit. See Section 3 Electrical  AC

Wiring Diagram, Page 39, for correct wiring to the heater

disconnect switch.

CAUTION:

Do not acti vate the  AC circuit unless the

engine cooling system has been filled.
A pre-mix solution must be used. Chemical

reactions will occur if pure Ethylene Glycol

anti-freeze is allo wed to f ill the heater ca vity

with AC circuit is activated.

HEAT EXCHANGER COOLING

The heat e xchanger cooling system is illustrated in Fig.  1,

Page 25.

Raw water from the f ire pump passes through the heat e x-

changer core where it lowers the engine coolant temperature

10-15° F (-12° – -9° C). Typical raw water connection points

on the heat exchanger are shown in Fig. 7, Page 29.

HOSES

Specific areas on each DDFP engine use hoses to transfer

coolant to and from heat exchangers and immersion heaters.

Regular inspections are necessary to v erify that no leaks

exist. Should replacements be required contact your local

DDC Distributor/Dealer for assistance.

NOTE:

Silicon Hose material for the immersion heaters

must meet SAE J20 Requirements with a maxi-

mum heat operating range of 350° F (177° C). Do

not replace these hoses with any other type materi-

al.

NOTE:

Hose clamps required for silicon type hose, must

have a shielded inner band or be of a constant

torque type (spring loaded). If the second type is

used, do not collapse spring by over tightening.

SECTION 3.4

DDFP

Fig. 8 - Typical Cooling Loop

Page 29

Fig. 6 - Engine Heaters

Fig. 7 - Raw Water Connections

I-53

V-92

I-53

V-71 or V-92

V-71

I-71

DDFP

SECTION 3.4

Page 30

RAW WATER SYSTEM (Cooling Loop)

This system is provided by the pump manufacturer or pump

assembler as part of the complete engine-pump-controller

package. Components for the raw water system are selected

to ensure adequate flo w through the heat e xchanger as

required by the engine at specif ic ra w w ater temperature.

The raw water system is generally referred to as the "cool-

ing loop".  A typical cooling loop includes the follo wing

components as shown in Fig. 8, Page 29;

1. Indicating manual valves

2. Water strainers

3. Pressure regulator

4. Solenoid valve (DC)

5. Pressure gauge

The heat e xchanger discharge line should be one pipe size

larger than the supply line. Additionally, it is recommended

that the discharge line rise a minimum of 3" to maintain raw

water across the entire cooling core. Discharge is made to an

open waste cone as specified in NFPA-20. 

CAUTION:

Damage to the heat exchanger may result if

raw w ater plumbing (supply or dischar ge) weight or

stress is applied to the heat e xchanger.

The solenoid valve may be omitted on vertical turbine pump

installations where no static pressure e xists in the heat e x-

changer supply line while the engine is not running. Each

engine has a minimum requirement of ra

w w ater flo w.

Correct flow through the heat exchanger is critical for main-

taining the proper engine operating temperature.

Engine coolant temperature can be adversely affected by in-

sufficient raw water flow and by excessive ambient tempera-

ture of the ra w water. See the technical data Section 5 for

each engine model's minimum raw water flow requirements

at 60° F (16° C) and 95° F  (35° C) at specified engine RPM

ranges. Do not exceed raw water pressure allowance within

the heat exchanger.

NOTE:

Although engine operating temperature may

appear normal, engine cooling may be compro-

mised and possible engine damage will result if

raw water flow is reduced.

ZINC ELECTRODE

A sacrifical zinc anode is included with each heat e xchang-

er. Over a period of time, normal electrotic action will occur

between dissimiliar metals within the heat e xchanger. The

rate of material transfer is dependent on the electrolitic

strength of the transfer media (ra w w ater). It is the zinc

anode that gi ves up material in this process and thus pre-

serves the integrity of the heat exchanger.

MAINTENANCE AND SERVICE PROCEDURES

Weekly

1) Check coolant level weekly. The level should be within

two inches of the filler neck. Because this is a closed sys-

tem, when operating temperature is reached,the pressure

relief cap may allo w some e xcess coolant to e xpell out

the o verflow tube until a stabilized le vel is reached.

Refer to procedure for filling engine in this section.

Check the condition of the pressure relief cap.  The rubber

seat should be in sound condition. If it is crack ed, split or

frayed, do not use. Do not attempt to run engine without a

pressure cap. Each cap has a relief rating, which is not to be

altered if a replacement cap is required. Refer to Section 5

for specific cap type and rating for each engine.

2) Inspect all hoses for leaks, repair or replace as necessary.

Annually

Check coolant inhibitor concentration, if not within v alues

shown in Fig. 2 re-inhibite as necessary.

Check Zinc Electrode, if more than half is deteriorated elec-

trode should be replaced. Contact your local DDC

Distributor/Dealer for replacements.

Every Two Years

Change all hoses.

ENGINE OPERATING SYSTEM

The DDFP engines used for f ire pump service include tw o

electrical systems. F irst is the engine heater system (A C),

second is the engine starting system (DC).  The starting and

control circuits are inte gral with the DC wiring harness b ut

are separated for explaining operation, maintenance and ser-

vice procedures. Engines are supplied with either a 12 or 24

V-DC system. Depending upon the specif ic model (refer to

Section 5).  This includes a starting motor, battery charging

alternator, wiring harness, battery insulator, manual contac-

tors, run-stop solenoid and tw o battery systems. F or identi-

fication reasons only, usually 12 V-DC systems have 2 bat-

teries, 24 V-DC systems ha ve 4. Under normal operating

conditions, signals for running and shutdown are transmited

from the AEC. With the controller switch on "automatic", a

specific drop in the fire main line pressure or other pre-pro-

grammed signal will result in a start of the diesel engine.

Reference the DC wiring diagram Fig. 13, Page 37 or Fig.

14, Page 38.

CAUTION:

These engines have been pre-set for a specif ic

operational speed (RPM).  When started, the

engine will quickly reach this setting.  The en-

gines do not have idle speed settings. With the

AEC switch on "T est", the engine can be test

started from the controller using either battery

system A or B. Engine stopping is accom-

plished by switching the controller selector to

the "Off" position. Consult the AEC operating

manual for specific operational instructions.

NOTE:

Prior to turning the  AEC to an y position other

than automa tic, please read the paragraph

labeled "IMPORTANT" in Section 2, Page 11.

The engine DC starting and control system terminates at the

DC junction box. The junction box location varies on differ-

ent engine models, one is typically sho wn in Fig. 5. From

this point, the engine is electrically connected to the auto-

matic engine controller (AEC). Both automatic operation

and test signals are sent to the engine from the  AEC. Under

emergency conditions, and if the AEC should become defec-

tive or disconnected from the engine for an y reason, it is

possible to start the engine by operating the manual contac-

tors. Specific emergency operating instructions are attached

to the instrument panel and explained in detail under MAN-

UAL STARTING of this section. Engine wiring diagrams

for AC and DC systems are shown in this section.

SECTION 3.5

DDFP

Page 31

ELECTRICAL SYSTEM

ENGINE HEATERS

NFPA-20 specifications require that the engine coolant be

maintained at 120° F (54° C) minimum. Additionally, if the

pump room temperature should fall below 50° F (10° C), an

engine oil heater is recommended. Both coolant and oil

heaters use AC power. 

All Clarke DDFP engines include immersion heaters.  Typi-

cally these heaters are mounted at the front of the engine.

Some models ha ve horizontal mounting and others are

mounted vertical. See Fig. 6, Page 29. Heater w attage rat-

ings v ary with engine size. (Refer to Section 5). 

These

heaters are wired to an  AC junction box mounted on the

engine.

CAUTION: SHUT OFF AC VOLTAGE BEFORE

SERVICING ENGINE HEATER

Installation - Jacket Water Heater, Thermostat

Fig. 1