Troubleshooting - Webasto Thermo Top Installation Instructions Manual

Troubleshooting

Error Symptom
Heater can't be switched on
Heater fails to ignite, fan motor is operating
Heater operates for a few minutes only
Insufficient heat output
Vehicle fan fails to switch on when the thre-
shold temperature (>30° of coolant) is
reached
Blue smoke or soot in the exhaust gas,
heater is emitting smoke
Possible cause
Heater is in the overheating lock-out mode
Summer/winter switch in summer position
Discharged battery
Defective fuse
Defective digital timer
Break in the power supply to the digital timer
Break in the power supply to the heater
Intermediate fuel reservoir empty
Heater not seated properly in its support, exhaust gas is
aspirated
Fuel lines of heater not properly connected. Flow and return
pipes were interchanged.
A non-return valve may have been installed in the fuel line
between heater and vehicle tank, or in the vehicle tank itself
(intermediate fuel reservoir is not ventilated).
Kinked coolant hose or system has not been bled completely
Heater control lever or vehicle fan out incorrectly set
Defective fuse F3
Kinked or blocked suction or exhaust gas line
Installation fault, heater is not properly seated in its support, or
gasket of exhaust gas pipe was not installed
Remedy
Remove 15A fuse
Determine cause
Switch to correct position
Charge
Replace
Use testing device on heater and check if digital timer switches properly:
disconnect connector X14 from heater, connect testing device and switch
on digital timer. The indicator lamp must light up; if not, the timer is defective
and the power supply to the timer is disrupted.
Alternatively: Check if 12 V voltage is present across contact 1 (6-pole
connector).
Check if 12V voltage is present across the red and brown wires of the
connector of the digital timer. If necessary check fuse F2 and cables wires.
Disconnect connector X 15 from the heater and use the testing device to
check for presence of voltage.
Allow vehicle engine to run for approx. 30 seconds
Loosen 2 M6 screws and position correctly
Connect fuel lines in accordance with installation instructions
Check line routing, bleed cooling system (start engine)
Prior to operating the heater set heater control lever to "warm" and set fan
switch to a higher setting.
Replace fuse
Check lines for unobstructed passage
Check installation
Thermo Top
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