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fuel as the engine. Do not operate in a closed
building or while refueling. Operate only in a
well ventilated area.
SWITCHING THE HEATER ON
The timer light illuminates when the heater is
switched ON. Air is forced in to flush out the
combustion chamber of residual gases and the
water circulation pump begins operating. The
fuel metering pump delivers fuel in precise
amounts to the combustion chamber, where fuel
and combustion air form a combustible mixture
which is ignited by the ignition unit.
Once the flame sensor has signaled to the
control unit that combustion has taken place, the
ignition unit is switched OFF.
Hot combustion gases are diverted at the end of
the flame pipe and are then forced through the
indirect heating surfaces of the heat exchanger.
The heat exchanger transfers the heat to the
coolant
water
passing
exchanger.
LOCATION OF PREHEATER
The heater is thermostatically controlled and
operates intermittently (i.e., the switched-on time
of the burner varies depending on the heat
requirement).
The
water
controlled by the built-in water thermostat.
The water circulation pump remains in operation
as long as the heater is operating, even during
through
the
heat
18607
temperature
is
PA1627 X3-45 Operator's Manual
Other Features
the regulated intervals and during the delayed
cut-out of the heater. The pump can also be
operated independently of the heater by means
of an appropriate circuit. The heater can be
switched ON at any time (i.e., during the delayed
cut-out period).
Ignition takes place after the
delayed cut-out time expires.
SWITCHING THE HEATER OFF
The fuel supply is interrupted when the heater is
switched OFF. This causes the flame to go out
and a delayed cut-out of 2.5 minutes begins.
The circulating combustion air flushes the
remaining combustion gases out of the chamber
and cools off the heated parts on the exhaust
side
of
the
heat
exchanger.
circulation pump continues to transfer the latent
heat present in the heat exchanger, thus
preventing hot spots. Once the delayed cut-out
time expires, both the combustion air blower and
the
water
circulation
automatically. A cut-out will automatically take
place in case of heater failure. Refer to
Technical Information chapter for additional
information.
COOLANT HEATER TIMER
The timer, located on L.H. lateral console is
used to program the starting and stopping time
of the preheating system and to give Fault
Codes. The system indicator light, located on
the timer, illuminates when the system is
functional. Your vehicle is equipped with timer A
or timer B.
TIMER A: OPERATING INSTRUCTIONS
TIMER
These instructions refer to the Spheros timer
illustrated above.
5-27
The
water
pump
switch
OFF
22223
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Troubleshooting
