Webasto DUAL TOP RHA-100 Workshop Manual - page 13
Dual Top
3 Fault code output
305
Message 08
Failure heating air
ventilator
Hot air motor fault: disconnection /
short circuit / fan speed out of range
/ fan blocked
1 Check power supply:
Fuse correct (fuse not damaged, 10A fuse used for
PWM module) and functioning.
All contacts are correct (no corrosion).
Voltage correct (>12V).
Restart heater.
2 Start blower: component test in diagnostic mode.
Run blower 5 minutes at 80%.
Listen if there is any unusual noise (grinding, etc.).
Restart heater.
3 Dismount application parts until the fan is visible.
Check if dirt, screws, objects or deformations block
the fan.
Check fan clearance with your finger (no high force!).
Remove all matters that block the fan.
Restart heater.
4 Remove service cap.
Check all electrical connectors.
Moisture in connectors (2-pin connector and 4-pin
connector)?
Moisture in connectors or on PWM module?
PWM module dark or burned?
12V power supply permanently available at PWM
module? (measure voltage between brown and red/
blue cable contacts of 4-pin connector) If not, check
external wiring harness: routing wiring harness and
pins of 12 pin connector.
In case there is a bad connector, bad wiring harness or
defect PWM module: replace defect part.
5 If heating air blower assy and wiring harness have
been checked and Dual Top still doesn’t run: replace
complete Dual Top.
Message 09
Failure ventilator
amplifier
No communication between
amplifier of heating air ventilator
and heaters control unit
1 Check internal cable routing (4-pins) from control unit
to PWM module.
2 Replace heating air blower assy.
3 Replace thermo unit.
Message 10
High temperature
sanitary water
Overheating water temperature
sensor
1 Check water level, reset heater (by pressing OK or
switching off for at least 5 sec.) or select winter mode
without hot water production.
2 Check fuel pump cable and connectors.
3 Check internal wiring harness connections Y9, Y10.
Message 11
High temperature
sanitary water
Exceeding gradient water
temperature sensor
1 See message 10.
2 Check if hot and cold water pipes have been
connected correctly.
Message 12
High temperature
heating air
Overheating hot air temperature
sensor
1 Ensure that hot air can flow freely, air intake and
outlets are not blocked.
Reset heater (by pressing OK or switching off for at
least 5 sec.)
2 Check fuel pump cable and connectors.
3 Check internal wiring harness connections Y9, Y10.
4 Check correct assembly of hot air temperature sensor.
Message 13
High temperature
heating air
Exceeding gradient hot air
temperature sensor
See message 12.
Message 14
Failure cooling air
ventilation
Overheating of heaters' control unit Ensure that cooling air can flow freely,
reset heater (by pressing OK or switching off for at least
5 sec.)
Message 15
Failure combustion air
motor
Combustion air motor interrupted
1 Ensure that cooling fan can freely rotate,
remove possible blocking objects.
2 Check fuse 15 A.
3 Check connector Y1 at control unit.
4 Change Drive Assy.
Message 16
Failure combustion air
motor
Combustion air motor fault:
disconnection / short circuit /
overload / blocked
See message 15.
Table 302: Fault messages programmable Control Panel
Message
Meaning
Remedy