Alde COMFORT 2923 Instructions D'emploi page 15

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.
5:0 Maintenance of the heating
system
Check regularly the level of liquid for the heating system in
the boilerʼs 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
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 concentra-
tion 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 reasons 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.
Donʼt 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 top-
ping 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 bottom 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 anti-freeze. Radiator
cement must not be mixed in the system.
5:1 Bleeding the heating system
When filling the system, air pockets may form, depending 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 circula-
tion 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
GB
vessel. Stop the circulation pump for a few seconds and they
usually disappear.
Figs 8-9 A. Air screw
6:0 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 gaseous down to -40
tane works unsatisfactorily below 10
is the most suitable type.
When the cylinder valve is opened, the LPG liquid is released as
-25
a gas. When LPG burns, carbon dioxide (CO
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 friendly and does not generate soot
on complete combustion. It can be stored in cylinders for any
length of time without its quality deteriorating. LPG is entirely
free of poisonous substances.
The risk with gas is that leaking gas is ignited, resulting in an
explosion. As LPG has no distinct aroma, sulphur compounds
are added that give a distinct, pungent smell, even when the
concentration of gas is as low as one fifth of the lower explo-
sion limit. The LPG burner usually works at a lower pressure
than the pressure in the cylinder. Low pressure is obtained by
allowing the LPG to pass through a regulator.
7:0 Troubleshooting
Here is a brief troubleshooting chart that may be of help in the
event of simple faults.
The ignition spark comes but the boiler does not start
1. Check gas supply.
2. Is the service tap fully open?
3. If the boiler has been out of use for a while or if the gas
cylinder has been changed, it takes longer to ignite than
normal.
4. The thermostat knob must be pushed down as far as it will
go when starting.
5. If this does not help, contact your service workshop.
No ignition spark
1. Check that there is a 12-volt supply to the boiler.
2. Check the fuse on the boiler is intact.
3. Check that the warning light for the ignition spark is flas-
hing.
4. Remove the lower front cover. Check that the cables to the
ignition transformer (small black box just under the control
panel) and the microswitch (under the thermostat) are pro-
perly attached and that there is no corrosion on the cable
clips.
5. If this does not help, contact your service workshop.
The boiler ignites but goes out when the thermostat knob
is released
1. Repeat the ignition procedure as per instructions in chapter
2:2 (wait 3 minutes before igniting the boiler again). Make
sure that the thermostat knob is pushed down as far as it
will go and hold it in position for 20-30 seconds after the
warning light has gone out.
2. Check that the pilot flame comes into contact with the tip of
the thermoelement (to the right of the pilot burner).
3. If this does not help, contact your service workshop.
The boiler boils
B. Air
C, while bu-
°
C. That is why propane
°
) and water vapour
2
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