10. Built-in devices 163
k
m
n
o
Diagram of Frost Control
Safety valve for boiler (Frost Control)
FrostControl
FrostControl is a non-electric safety or drain valve. If there
is a risk of sub-zero temperatures it automatically drains the
content of the boiler via a drain outlet.
If the system is under excess pressure intermittent pressure
equalisation will automatically take place via the safety valve.
k
Rotary switch position “ON”
m
Push button position “CLOSED”
n
Push button position “DRAIN”
o
Drain outlet (to the outside through the vehicle floor)
To activate
• Push in the knob at position (
m
) slightly and, at the same
time, move it 90° towards position (
k
).
• If the switch is in position (k), the knob will remain in position (
m
).
To deactivate
• Turn the switch at position (
k)
by 90° so that it is parallel to
the frost control.
• At the same time, the knob will jump from position (
m
) to (
n
).
The drain valve can only be closed manually using the
push button (Position
m
) and the boiler filled if the valve
temperature is above approx. 7°C.
If the temperature of the safety/drain valve is lower than approx.
3°C, the push button will be ejected (Position
n
) and the con-tents
of the boiler will be drained off via the drain outlet (
o
).
k
