- Fill up the coolant and check now whether there are any
leaks.
- Venting work may have to be carried out. Ask the manufac-
turer of the vehicle about this.
- Mix the coolant as indicated on the packaging or as prescri-
bed by the manufacturer when it is replaced.
- Fill the coolant expansion tank so that the coolant level is
between minimum and maximum, wait a few minutes and
then screw on the cap of the expansion tank.
- Start the engine and set the passenger compartment hea-
ter/air conditioning to maximum warm.
- Let the engine run till it hand-warm. Make sure that
everything is tight and that the coolant level does not drop
below minimum. If necessary, switch off the engine, top up
the coolant and repeat the previous steps.
Caution, the expansion tank may be under pressure! Danger
of scalding!
- After the coolant level remains constant, let the engine
run until it reaches operating temperature. If you notice any
leaks, switch off the engine immediately, let it cool down
and remedy the leak.
- As soon as the engine has reached operating temperature,
switch it off and let it cool down.
- Check the preheater for leaks; coolant must not leak at any
point.
- If everything is tight, the preheater can be put into opera-
tion after driving a few kilometres and allowing the engine
to cool down by connecting the connecting cable to a power
outlet.
The passenger compartment heater must be set to maximum
„Warm“! If noises other than a „soft whir“ occur during ope-
ration of the preheater, there is air in the cooling circuit. This
can lead to the destruction of the pump unit. In this case,
bleed the cooling system again.
- If all conditions are fulfilled, the preheater can be opera-
ted.
- The preheater is not designed for continuous operation.
Always make sure to set the passenger compartment heater
to „warm“ before operating the preheater.
Function and protection of the engine preheater
The engine pre-heater heats the coolant in intervals of ap-
prox. 15 minutes.
As soon as the preset temperature is reached, the unit swit-
ches off automatically. If the temperature of the coolant then
drops again to a value of approx. 5-15°C below the prehea-
ting temperature, the unit switches on again automatically
and starts the cycle again.
If, for example, the pump is blocked by impurities, the unit
switches off automatically. If this switch-off should fail or not
work due to air in the cooling water circuit, the unit switches
off automatically at 145°C by destroying the integrated fuse.
After that, the preheater is no longer to be used. In the event
of fault currents or moisture in the connection system, the
upstream RCD switches off automatically.
Questions and answers
For which vehicle engines is the engine preheater suitable
for?
The engine preheater is suitable for all liquid-cooled com-
bustion engines. The heater is less suitable for engines
with a large volume (e.g. lorries, construction machines or
transporters) due to its heating and pump capacity. This also
applies to systems where the engine and heater radiator are
more than 80 cm apart. If the heater is to be used for such
engines/systems, parallel operation of 2 heaters is recom-
mended.
Can the pre-heater be used with LPG / vegetable oil vehi-
cles?
Vehicles with bivalent fuel (LPG/petrol) are always started
with petrol in cold start. Switching to LPG is only possible
after the engine has transferred heat to the coolant. The
reason for this is that the LPG evaporator needs heat in order
not to ice up.
In pure short-haul operation, therefore, the vehicle is often
driven on petrol and not on gas. The pre-heater also supplies
the LPG evaporator with warm coolant and the vehicle can
thus be switched to gas operation more quickly. A similar
function is also found in engines that run on vegetable oil.
Is it possible to use the pre-heater as an interior heater?
The primary goal is to preheat the engine and thereby redu-
ce wear, emissions and fuel consumption. Due to the way it
is installed (return from the heater radiator), the passenger
compartment heater is also supplied with warm coolant. Ho-
wever, the heat dissipation to the passenger compartment is
low, as only convection heat is released here. Useful heat is
only available after the engine is started and the ventilation
fan is switched on. In principle, it is possible to switch on
the fan to warm the interior.
What is the difference to other pre-heaters?
Most pre-heaters work on the principle of convection. These
heaters are set directly in the engine / core plug (sometimes
even several at the same time). Special heaters are required
for each engine type. Only selective heating of the engine is
possible and the heating times are up to three hours.
This engine preheater is a universal pump preheater of the
smallest design, which also finds its place in modern or
even narrow engine compartments. The integrated pump
transports the coolant continuously. The heat generated is
thus distributed evenly and quickly. This allows higher tem-
peratures to be generated at the same output as with non-
pump-operated pre-heaters. The heating times are reduced
considerably.
