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Tips and Tricks, Truma Combi's freeze control valve

Help: When I turn on the pump, water comes out from under the campervan, when I turn it off, the water outlet stops. How can I fix? You won't believe it but everything is fine, at least in 99% of cases I will explain why.


İpuçları ve Püf Noktaları, Truma Combi'nin donma kontrol valfi
İpuçları ve Püf Noktaları, Truma Combi'nin donma kontrol valfi

The hot water boiler is equipped with an automatic system that prevents the stove/boiler from being damaged by freezing water. It is called the Frost Control valve (or ELASI) and has two versions:


  • the first one is electrical and it empties the contents of the boiler when the room temperature drops below 4 degrees or the battery voltage drops too low (and therefore also turns on when you disconnect the battery). It consists of a small black box with a red button at the top: when the button is up the valve is activated (closed), when the button is down the valve opens and drains the water to the ground (outside the campervan)

  • the second is mechanical and empties the contents of the boiler when the ambient temperature drops below 4 degrees. It consists of a black (sometimes gray) box with a blue switch at the top and a blue button at the bottom. When the button is out, the valve is open and therefore the water is discharged to the ground. To close (reset) the valve, turn the key (it should be perpendicular to the axis of the black box) and press the button.

Why is it important to know the existence and functioning of this valve ? Because when you go to tour the caravan (especially in winter), you will need to take water and therefore you will have to fill the boiler. When you turn the pump on it will start bringing water to the boiler, but if the valve is open the water will come out and continue to come out from under the caravan until you turn off the frost control.


To reset the valve, if it is cold, turn on the stove and wait a few minutes for the temperature in the Truma chamber to rise slightly.


Some suggest methods to prevent frost control and prevent water from draining from the boiler: DO NOT leave the valve empty for proper operation, better to lose 10 liters of water than risk damaging the Truma Combi.


Remember: on winter trips the heating must ALWAYS be left on day and night for the following reasons:


  • prevents (or reduces) the risk of water freezing in the water system

  • maintains the temperature inside the caravan

  • prevents the frost control valve from opening and draining the boiler ( remember to always turn off the pump when you are not using water, at night and when you leave the caravan )

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