Water Heater; Maintenance Of The Heating System; Useful Facts About Lpg; Bleeding The Heating System - Alde Comfort 2928 Instructions For Use Manual

6. When you want the heating to start up, reconnect
the 230/240-volt cable. The immersion heater and
the circulation 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 maxi-
mum 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,
particularly 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 water-
tank. 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 sys-
tem 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 tempera-
tures lower than -25 C , the glycol content should be
°
raised, but must not exceed 50%. The percentageg-
lycol 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 en-
sure 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 vehicle is parked horizontally be-
fore 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 up-
wards, 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 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 (the vehicle's
instruction book will show you where they are located).
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. Jack up the vehicle at the
back 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 raise
the vehicle at the front and repeat the procedure in this
position (see fig 9). Place the vehicle 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 bleeding caravan systems, the easiest way
of raising and lowering the vehicle is by using the sup-
port wheel. 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
B. Air
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
turns in released as a gas. When LPG burns, carbon
dioxide (CO ) and water vapour only are emitted, just
2
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
15