vehicles equipped with a TRUMA COMBI water heater and heating system (Fiat 4) have a safety valve. You can find this valve in the back of the motor home usually under the bed (2008 modes) or inside the cupboards (2015 models)

A. FrostControl

(Safety/drain valve with integral frost protection 

FrostControl is a currentless safety/drain valve. When there is a danger of frost, it automatically drains the contents of the boiler through a drainage socket. If excessive pressure is present in the system, pressure will be automatically intermittently equalized through the pressure relief valve.

Figure 3

a = rotary switch position “On”

b = pushbutton position “Closed”

c = pushbutton position “Drain”

d = drainage socket (led outside through floor of vehicle)

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 contamination

(slush, ice, leaves, etc.) at all times so the water can

drain out easily! No claims may be made under the warranty

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 inserted into the FrostControl and fixed

in place with a retaining bracket. This heating element heats

the FrostControl to approx. 10 °C when the Combi is switched

on.This means that the boiler can be filled sooner, irrespective

of the temperature in the installation compartment.