Webasto GBW 300 Installation instructions manual - page 51
Connection to the vehicle cooling system
GBW 300
48
10
Connection to the vehicle cooling system
The heater is connected to the vehicle cooling system as shown in
Figs. 3 and 4. The system must contain at least 10 litres of coolant.
The water hoses must at least comply with DIN 73411. The hoses must
be installed without kinks and (to ensure perfect bleeding) rising if
possible. Hose connections must be supported by hose clips to prevent
them slipping.
NOTE:
The hose clips must be tightened with a torque of 1.5 Nm. Ensure that
the water hoses have chafing guards and can move freely.
Only pressure valves with an opening pressure of min. 0.4 bar and
max. 2.0 bar may be used in the vehicle’s cooling system.
The cooling system must be bled carefully before using the heater for
the first time or after replacing the coolant. The heater and lines should
be installed in such a way as to ensure static bleeding. Any shut-off
cocks in the cooling system must be opened.
Perfect ventilation can be identified by the circulating pump operating
almost silently. Poor bleeding may cause the temperature limiter to trip
whilst the heater is operating.
If you use the U 4851 circulating pump, the pump will cut out
automatically approx. 15 seconds after it is switched on if there is
insufficient coolant or the pump impeller is blocked and can be restarted
after approx. 2 minutes.