Alde Comfort 2923 Betriebsanweisung Seite 15

GB
5. Disconnect the 230-volt cable from the external
power supply.
6. When you want the heating to start up, reconnect the
230-volt cable. The immersion heater and the circu-
lation pump will then start up thanks to the battery
eliminator transforming down the voltage to 12 volts.
4. wATER HEATER
The LPG boiler can be equipped with a stainless steel
water heater, with a volume of 7 litres of stored fresh
water. A maximum capacity of about 12.5 litres of hot
water at 40 C can be obtained.
°
When the water heater is to be used, the LPG boiler
should be started about 20 minutes in advance, and run
at maximum boiler temperature to obtain the maximum
amount of hot water. If an immersion heater is used
instead of gas, the heating period is longer.
Always flush out the water heater before it is used, par-
ticularly when it has not been used for a some time.
NB. Although the water heater is protected against
frost, fresh water in the heater must always be
drained out when there is risk of frost and the vehi­
cle is not in use.
Drain the heater like this:
Empty the fresh water tank. Open the drain cock on the
water pipe (fig 6 b), and the air screw (fig 6 c) on the
heater and empty out the water in the heater. If there is
no drain cock, release the hose from the nipple on the
heater instead. Allow it to stand like this until you use the
vehicle again.
If the vehicle is equipped with a pressure-controlled
pump, it must be switched on. Drain the fresh watertank.
Open the water taps and empty the fresh water system.
Switch off the pump. Open the drain cock on the water
pipe (fig 6 b), and the air screw (fig 6 c) on the heater
and leave taps open. Allow it to stand like this until the
vehicle is to be used again.
5. MAINTENANCE OF THE HEATING
SySTEM
Check regularly the level of liquid for the heating system
in the boiler's expansion vessel. The level should be
about 1 cm above the min. line when the boiler is cold.
The system should be filled with a 40% glycol mixture of
the same type as used in car engines (not diesel). If the
heating system is exposed to temperatures lower than
-25 C , the glycol content should be raised, but must not
°
exceed 50%. The percentageglycol content should be
checked before more liquid is added. This is to prevent
an excessive concentration of glycol in the mixture.
The glycol mixture should be replaced every other
year, as its properties, such as corrosion protection,
deteriorate.
Never let the heating system stand without the glycol,
water liquid.
If the liquid level in the expansion vessel falls for rea-
sons other than pure evaporation, check that all joints,
the drain cock and air screws are tight. If glycol water
has leaked out, rinse with water and mop up.
Don't forget to check the gas system regularly to ensure
that connections and hoses are not leaking.
LPG hoses should be replaced every other year as they
dry out and crack, which may give rise to leakage.
Topping up with liquid:
Make sure that the caravan is parked horizontally before
topping up, so that no air pockets can be formed. Check
that air screws and the drain cock are closed. Remove
the upper front cover (see fig 7) pull it upwards, the bot-
tom outwards and then downwards. Release the nut on
the expansion vessel and lift up the pump. Pour in the
glycol mixture slowly.
NB. Alcohol must not be used as anti­freeze.
Radiator cement must not be mixed in the system.
5:1 Bleeding the heating system
When filling the system, air pockets may form, depend-
ing on how the system was installed. A sign that there is
air in the system is when the heat will only travel a few
metres along the radiator system from the boiler, even
though the circulation pump is running.
Bleed the system like this:
The boiler should be running and the circulation pump
off. Start by opening the air screws. Leave them open
until water comes out of nozzle. Start the circulation
pump and allow it to run for a while. Feel the pipes and
radiators in the vehicle to see it they are getting warm.
If it is hard to get the air out of the system, you
can do as follows:
Stop the circulation pump. Roll down the support wheel
as far as it goes, so the caravan lean forwards at the
front or park it on a downhill slope (see fig 8). Allow it
to stand a few minutes so that the air gets to the top of
the system. Open the air screw at the highest point and
leave it open until the air has come out. Then roll up the
support wheel to maximum or park it on a upphill slope
and repeat the procedure in this position (see fig 9).
Place the caravan on the level and start the circulation
pump. When flow and return pipes are almost the same
temperature, the system is free of air. When the system
has just been filled, small air bubbles may form in the
expansion vessel. Stop the circulation pump for a few
seconds and they usually disappear.
Figs 8­9 A. Air screw
6. uSEFuL FACTS ABOuT LPG
LPG is a petroleum product and the letters stand for
Liquefied Petroleum Gas. It is available as propane
and butane. Propane has the advantage that it is gase-
ous down to -40 C, while butane works unsatisfactorily
°
below 10 C. That is why propane is the most suitable
°
type.
When the cylinder valve is opened, the LPG liquid is re-
leased as a gas. When LPG burns, carbon dioxide (CO
and water vapour only are emitted, just like in the air we
breathe out. In order for combustion to be complete, a
good air supply is required. LPG is very environment
B. Air
)
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