The changeover unit for the gas system
Automatic changeover from empty to full gas cylinder
To avoid having to change an empty gas cylinder immediately, there is a convenient solution: an automatic changeover system, also called a two-bottle system. Here I explain which automatic changeover systems are available and how they work.
Table of contents
How does a changeover system work?
The system has two connections for two gas cylinders. In this setup, a distinction is made between the operating cylinder and the reserve cylinder. As soon as the gas pressure in the operating cylinder drops, meaning the gas is used up, the system automatically switches to the reserve cylinder and draws the required gas from it.
You can then replace the empty cylinder with a full one and adjust the regulator so that the partially used cylinder becomes the operating cylinder and the newly inserted full cylinder becomes the reserve cylinder.
In diagrams 1 and 2, the changeover regulator B is set to reserve and gas is primarily drawn from the cylinder with the central regulator A (operating cylinder).
In diagrams 3 and 4, the operating cylinder has been replaced and the changeover regulator B is set to operating mode. Only when the pressure in this cylinder drops again will gas gradually be drawn from the full cylinder. © Manufacturer text
What types of systems are available?
The automatic 2-cylinder changeover system Multimatic with integrated gas pressure regulator and overpressure safety blow-off function for stationary operation.
Here you can find the two-cylinder system from HPV in the Berger online shop.
GOK Caramatic BasicTwo two-cylinder system for mounting directly onto the gas cylinders.
Here you can find the two-cylinder system from GOK in the Berger online shop.
GOK Caramatic ProTwo 30 mbar without crash sensor (left in the image)
Here you can find the Caramatic without crash sensor in the Berger online shop.
or GOK Caramatic DriveTwo with crash sensor (right in the image)
Here you can find the Caramatic with crash sensor in the Berger online shop.
Truma DuoControl CS available in vertical or horizontal versions (with crash sensor).
Here you can find the DuoControl from Truma in the Berger online shop.
How much does a gas changeover system cost?
For a GOK Caramatic ProTwo without crash sensor but including hoses and filter, you should expect to pay around €270.
For a Truma DuoControl with crash sensor, hoses and filter, you should expect costs of around €370.
Systems with crash sensor
The crash sensor prevents uncontrolled gas leakage in the event of an impact by shutting off the system. If the hose ruptures, the hose rupture protection immediately stops the gas flow at the cylinder, preventing unburned gas from escaping.
With Truma, the crash sensor is integrated into the DuoControl CS. GOK offers systems both with and without a crash sensor. If you want to operate the gas system while driving, a crash sensor and a hose rupture protection device are mandatory. These safety shut-off devices are required by law for vehicles first registered from 2007 if gas is to be used while driving. When arriving at your destination, it is especially convenient if your caravan or motorhome interior is already heated.
Important: Even if you do not intend to use gas while driving, a hose rupture protection device is mandatory for hoses longer than 1.5 metres, for example on a camping gas grill.
Who should carry out the installation?
Modifications to the gas system should always be carried out by a qualified professional experienced with gas systems. They can also perform the required gas inspection afterwards and record it in the inspection booklet.
The gas regulator system must be replaced every 10 years.
Since Truma and GOK products are largely similar in design, switching manufacturers after the service life has expired is easily possible and can be done with minimal time and cost.
What accessories are required for installation?
In addition to the safety gas pressure regulator, you will need two high-pressure hoses and a gas filter set.
With the Truma DuoControl CS, gas filters are mandatory, otherwise the warranty becomes void. GOK also recommends using gas filters to prevent damage caused by contaminated gas.
It is recommended to replace the filter each time the gas cylinder is changed.
Tip: With the DuoC remote indicator from Truma, you can monitor from inside the vehicle which gas cylinder is currently in use and when it needs to be replaced.
Conclusion: a convenient solution
You need to consider how much it is worth to you not having to go outside in the cold at night. For extended camping in winter conditions, an automatic gas changeover system can be a very convenient solution.
