Truma DuoControl Mode D'emploi page 12

Operating with only one gas cylinder
You can also use DuoControl with only one gas cylinder. Non
return valves integrated into the inlet connecting piece pre-
vent gas from escaping through the unused connecting piece.
The free inlet must be sealed off using the provided dummy
cover (brass) if only one cylinder is being used.
Turn rotary knob in direction of operating cylinder.
Leak-testing in the high pressure area
Leak-test the screw fittings for high-pressure hoses on the gas
cylinder valve and on the DuoControl changeover regulator
with appropriate equipment, such as a leak-detection spray
according to DIN EN 14291.
The low-pressure area should be leak-tested by a qualified
technician.
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