Fig. 801 Circulating Pump U4849 And U4847 Econ Installation Positions; General - Webasto Thermo Top V Workshop Manual

Thermo Top V
8 Servicing work
8.1

General

This section describes the servicing work that can be carried
out on the heater when it is installed.
WARNING
There is a danger of burns, as the heater and the attached
parts may be extremely hot.
8.2 Work on the heater
Disconnect the 20 A fuse for voltage interruption of the
heater or the main power cable from the vehicle's battery
before carrying out any work on the heater. The main bat-
tery power must not be disconnected whilst the heater is
operating or slowing down as a result of the risk of the
heater overheating and the overheating protection thus
being tripped. If extensive repair work is carried out on the
heater, it must be completely removed. After work is per-
formed on the heating circuit, a coolant mixture of water
and antifreeze must be added in accordance with the vehi-
cle manufacturer's specifications and the heating circuit
must be carefully bled.
8.3 Work on the vehicle
WARNING
A temperature of 120 °C must not be exceeded in the vicin-
ity of the heater under any circumstances (for example, dur-
ing painting work on the vehicle).
8.4 Heater trial
The heater must not be operated in enclosed areas such as
garages and workshops without an emissions extraction sys-
tem, even if you use the timer.
8.5 Servicing work
The following servicing work is to be carried out once a year
to maintain the functional reliability of the heater:
• Visual inspection of the heater for external damage, fas-
tening and, if possible, external cleaning (avoid penetra-
tion of water)
• Inspect electrical connections for contact corrosion and
firm seating and examine wiring routing (for cracks,
kinks or rub spots)
• Check the exhaust and combustion air lines for signs of
damage and to ensure that they are clear
• Check fuel lines for leaks (cracks, kinks or rub spots)
• Check coolant hoses and circulating pump (if present)
for leaks (cracks, kinks or rub spots)
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• Check fastening of circulating pump and metering
pump for damage
• Conduct operating test of heater as described in section
6.2.
8.6 Visual inspections and installation
instructions
8.6.1 Connection to vehicle cooling system
The circulating pump should preferably be integrated in the
direction of flow upstream of the heater and deep enough
in the coolant circuit so that automatic bleeding of the cir-
culating pump is ensured. The circulating pump must be
secured on the vehicle.
Fig. 801 Circulating pump U4849 and U4847 ECON in-
stallation positions
The pump can only bleed automatically if at least 1 connec-
tion piece opening is at least 5° over the horizontal plane.
WARNING
The correct direction of flow of the heater must be ensured!
Servicing work
NOTE
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