Webasto DUAL TOP RHA 100 Installation Instructions Manual page 18

Hot water system Dual Top
Avoid the flow of water from the heater back into the vehicle's fresh water
tank. Use one-way valves if required.
If the hot water temperature at the water outlets needs to be limited, use
a thermostatic mixing valve as an option (see Fig. 10).
D
When connecting to a central water supply (rural or city mains) or if using
a more powerful pump, a pressure reduction valve must always be installed
C
to prevent a pressure above 2.5 bar developing in the boiler.
Route water hoses as short as possible and free of kinks. All hose
connections must be secured in a way that they can withstand pressure
B
and are watertight (also cold water hoses)! The thermal expansion of the
3
water can cause pressures of up to 4 bar before the overpressure valve
reacts.
2
1
A
It's recommended to route all water pipes in such a way that they descend
towards the vehicle water tank. Route intake and outlet pipes connected
to the heater in such a way that there are no syphons. So, if you drain the
Fig. 12: Cold (A) and hot (B) water lines, air intake hose (C) and
boiler, you also drain the water lines.
Webasto dual adapter (D)
The water lines must be routed inside the heating air intake hose. This will
avoid frozen water lines as long as the heater is operating in a proper mode
(see Operating Instructions).
Use Webasto dual adapter to connect the air intake hose to the heater and
secure it with a clamp. See Fig. 12.
NOTE:
Do not secure the adapter with screws going through adapter and intake
cap. This can block the ventilators.
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