Alde Compact 3020 Manual De Servicio página 5

Rubber connection with automatic bleed and non-return
valve.
Expansion tank with non-return valve.
some cases the non-return valve may be located at the
expansion tank, see figure Expansion tank with non-re-
turn valve.
NB. Ensure that the direction of flow in the filling pump is
the same as the arrow on the non-return valve, otherwise
there is a risk of the non-return valve moving or turning.
NB. On some vehicles the tank may be reverse mounted,
which means that the flow runs in the opposite direction.
Bleeding the heating system in a caravan
(manually):
The boiler must be running and the circulation pump
turned off. Start by opening the bleed screws (see the ve-
hicle's instruction manual to find out where these are lo-
cated). Keep them open until fluid comes out of the pipe
at the bleed screw, and then close the screw. Start the
circulation pump and let it run for a while. You can also
increase the speed of the circulation pump (setting 5).
See if the pipes and convectors are heating up around
the caravan. Don't forget to return the circulation pump
to its original setting (setting 2) once you have completed
the bleeding operation.
If the air has still not come out,
you can try the following method:
The boiler must be running and the circulation pump
turned off. Crank the caravan's jockey wheel down as far
as needed to make it slope forwards. Leave it in this po-
sition for a few minutes to allow any air to travel upwards
in the system. Open the bleed screw located at the high-
est point and keep it open until all the air has escaped.
Now crank the jockey wheel up to maximum position
and proceed in the same manner in this position. Then
position the caravan horizontally and start the circulation
pump.Check that the heat is flowing around the caravan.
The easiest way to bleed the system in a twin-axle car-
avan or motor caravan is to park the vehicle on ground
which has a significant gradient or to raise one end of the
vehicle using a jack.
2. ABOUT THE COMPACT 3020
Layout of the boiler
The boiler consists of three eccentrically mounted pipes.
The innermost pipe is the heat exchanger, which is made
from extruded aluminium. Around this is the water jacket
for fluid to the heating system in which it is located. It
contains a 40% ethylene glycol mixture.
Outside the water jacket is the hot water heater, intended
for freshwater. The two outer pipes, and their end caps
and connections, are made of stainless steel.
The heat exchanger is split into two hemispheres by
means of a U-shaped baffle plate.
The burner is located in the top hemisphere, which forms
the combustion chamber. The baffle plate guides the flue
gases on their return path into the bottom section of the
profile, which forms the convection part.
The burner housing is welded in position on the end of
the heat exchanger.
On the burner housing are a fan, burner, solenoid valve,
and an intake as well as an exhaust gas connection. The
exhaust gases are expelled through the inner pipe and
the intake air is drawn in through the outer one.
The exhaust gases leave the vehicle via a hose connec-
tion through either a roof or a wall flue. The intake air is
also drawn in via the same flue (balanced draft).
The upper part of the water jacket has two electric ele-
ments inserted in it. The maximum rating of the elements
is 3 kW.
2:1 BOILER FUNCTION
The boiler is a combined unit for the production of heat
and domestic hot water. The energy sources used are
either electricity, LPG or a combination of the two, as well
as the AC system. The two electric elements are rated at
1 kW and 2 kW, respectively. The electric power output is
controlled via switches on the circuit board.
On start-up, full power output is not connected immedi-
ately, but connection is in two or three stages with a few
seconds delay between each of them. The boiler has a
burner which works in two stages. The lower stage is at
3 kW and the higher one at 5.5 kW. The power output
stage at which the boiler works is determined by the
heating need in the vehicle.
On the circuit board, all functions needed to monitor and
control the boiler are connected. These can be split up
into the following units:
• Monitoring and control of fan speed at the various
power stages.
• Opening of the gas valve's various power stages at the
correct moment.
• Ignition spark to the burner via the two spark plugs
fitted to the burner.
• M onitoring of the flame by means of a sensor plug
fitted to the burner.
• Control and monitoring of convector temperature via
sensors fitted to the boiler body.
• Control of domestic hot water temperature via a sensor
fitted to the heater.
• Control of room temperature in the vehicle via a sensor
in the control panel or a sensor connected to the control
panel.
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