Opening The Safety/Drain Valve; Closing The Safety/Drain Valve; Automatic Opening Of The Safety/Drain Valve; Filling The Boiler - Truma Combi D 4 Operating Instructions Manual

Opening the safety/drain valve

Turn the rotary switch by 180° until it engages, whereby the
pushbutton pops out (position c). The water from the boiler
drains through the drainage socket (d).
The FrostControl drainage socket (d) must be free of contami-
nation (slush, ice, leaves, etc.) at all times so the water can
drain out easily! No claims may be made under the war-
ranty for damage caused by frost.

Closing the safety/drain valve

Check whether the rotary switch is set to "On" (position a),
i.e. parallel to the water connection and engaged.
Close the safety/drain valve by pressing the pushbutton. The
pushbutton must engage in position (b) "closed".
Only when the temperature at the safety/drain valve is above
approx. 7 °C can it be closed manually with the pushbutton
(position b) and the boiler filled.
Truma supplies a heating element (part no. 70070-01) as an
accessory, which is plugged into the FrostControl and fixed in
place with a retaining bracket. This heating element heats the
FrostControl to approx. 10 °C when the Combi D is switched
on. This means that the boiler can be filled sooner, irrespective
of the temperature in the installation compartment.

Automatic opening of the safety/drain valve

If the temperature at the safety/drain valve is below about 3 °C,
it will open automatically and the pushbutton pops out (pos-
ition c). The water from the boiler drains through the drainage
socket (d).

Filling the boiler

Check whether the safety/drain valve is closed (see "Closing
the safety/drain valve").
When the temperature at FrostControl is below approx.
7 °C, first switch on the heater to warm the installation
compartment and FrostControl. The safety/drain valve can be
closed after several minutes, when the temperature at Frost-
Control is above 7 °C.
– Switch on the power for the pump assembly (main switch
or pump switch).
– Open hot water taps in the kitchen and bathroom (set pre-
selecting mixing taps or single-lever fittings to "hot"). Leave
the valves open until the boiler has been filled by displacing
the air and water is flowing without interruption.
Even if the cold water system alone is operated without
the boiler, the boiler will still fill with water. To avoid frost
damage, the boiler must be drained via the safety/drain valve,
even if it was not operated.
In the event of frost, filling may be prevented by frozen re-
sidual water. The boiler can be thawed by turning it on briefly
(no more than 2 minutes). Frozen lines can be thawed by
heating the interior.
If the boiler is connected to a central water supply (ru-
ral or urban connection), a pressure reducer must be
used, which will prevent pressures higher than 2.8 bar from
occurring.
14

Draining the boiler

If the motor home / caravan is not being used during
the frost period, the boiler must be drained!
– Switch off the power to the pump assembly (main switch or
pump switch).
– Open hot water taps in kitchen and bathroom.
In order to check the water that is flowing out, place an
appropriate container (capacity 10 litres) beneath the
drainage socket (d) of the safety/drain valve.
– Open safety/drain valve
(see "Opening the safety/drain valve").
The boiler will now be drained directly to the outside via
the safety/drain valve. Check whether all of the water in the
boiler (10 litres) has been drained into the container via the
safety/drain valve.
No claims may be made under the warranty for damage
caused by frost.

Initial start-up

(or when the fuel tank has run empty)

Filling the fuel lines

The heater normally has to be started up several times to fill
the fuel lines if an automatic filling device is not being used.
Check to make sure the cowl is unobstructed. Remove any
covers that may be present.
Switch off unit at control panel. The unit automatically per-
forms 2 starting attempts (initial start and repeat) per switch-
on procedure with a run time of 2 minutes in each case. If no
flame is detected after the repeat start, the unit switches to
fault and has to be switched off and on again at the control
panel.
After a total of 15 unsuccessful starting attempts (initial
and repeat start) without forming a flame, the equipment
is blocked. To remove the block, please contact the Truma
Service Centre or one of our authorised service partners (see
www.truma.com).
Check fuel lines and connections for leaks after filling the fuel
lines.

Start-up

The interior can be heated with or without water, depending
on the setting.
– Check to make sure the cowl is unobstructed. Remove any
covers that may be present.
– Fill boiler with water if necessary (see "Filling the boiler").
– Switch on the unit on the control panel.

Switching off

– Switch the heater off on the control panel.
– The switch-off procedure may be delayed by several min-
utes because of internal heater operations.
Always drain water contents if there is a risk of frost!