Fiat DUCATO Owner's Handbook Manual page 46

The additional heater (during winter)
heats, maintains the temperature of and
circulates engine coolant for a set time
period in order to ensure optimum
engine and passenger compartment
conditions at engine start-up.
The heater can operate automatically
when programmed with a digital timer
or manually by pressing the 'immediate
heating' button on the timer.
After heater activation, whether
programmed or manually, the electronic
control unit operates the coolant pump
and turns on the burner in accordance
with pre-set, controlled procedures.
The circulation pump output is also
controlled by the electronic control unit
in order to minimise the initial heating
time.
When the system operates, the control
unit turns on the passenger
compartment heater unit fan at the
second speed.
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The thermal power of the boiler is
regulated automatically by the
electronic control unit depending on the
temperature of the engine coolant.
IMPORTANT The heater is equipped
with a thermal limiter that cuts off
combustion in the case of overheating
due to insufficient coolant/coolant
leaks. In this case, after repairing the
fault in the cooling system and/or
topping up the fluid, press the program
selection button before turning the
heater back on.
The heater can turn off spontaneously
due to misfiring after start-up or
because the flame goes out during
operation. In this case, carry out the
turning off procedure and try to turn the
heater back on. If it still does not work,
consult a Fiat Dealership.
Activation of the heating
system
When an automatic climate control
system is present, the control unit sets
the air temperature and distribution
when the heater is turned on from the
park position. When a manual
heater/climate control is present, to
obtain maximum heater efficiency,
check that the passenger compartment
heating/ventilation temperature
adjustment knob is in the 'hot air'
position.
To prioritise passenger compartment
pre-heating, set the air distribution knob
to the position.
To prioritise windscreen demisting, set
the air distribution knob to
To obtain both functions, set the air
distribution knob to position.
position.