Switch On - Webasto Air Top 3500 Workshop Manual

Air Top 3500/5000
3 Functional Description
(Fig. 301)
3.1 Control Element
The control element is used to switch the heater on and
off, to set the desired room temperature (air intake
temperature between 5° C and 35° C), to reset the heater
after a malfunction with error lockout and to adjust the
CO value.
2
The integrated green LED indication is used as
• operating indicator light (LED permanently on)
• error code/overheat indicator (LED flashes)
Only applicable to ADR operation!
When applying electrical power with the control element
still set to "on", e.g. by closing the battery switch, the
control unit will go in error lockout. For re-activation the
control element must be momentarily switched off and on
again.
3.2

Switch on

The control element is to be set to the desired
temperature. When switching the heater on the operating
indicator light will illuminate. The motor of the combustion
and heating air fan runs up at low speed.
If the temperature of the combustion air taken in exceeds
the set temperature, the heater will enter control idle. With
the combustion air temperature below the set
temperature, the starting sequence commences.
The function of the glow plug/flame sensor is checked.
Should the glow plug/flame sensor already signal at this
stage "bright" for longer than 60 seconds, there will be a
150 second run-down and an error lockout of the control
unit. A malfunction of another component monitored
causes an error lockout without run-down.
NOTE
NOTE
3 Functional Description
Start
The glow plug/flame sensor is activated. After
approximately 22 seconds the dosing pump is put into
operation and combustion commences. After
116 seconds the glow plug is deactivated and the flame
sensor becomes active. After 136 seconds a check is
performed to verify a proper burning of the flame.
Detection of a flame will cause the flame to be stabilised
for 50 seconds by burning at 1.5 kW.
No flame detection will initiate a repeat start.
2nd Start (Repeat Start)
For this purpose the dosing pump is switched off and the
glow plug is activated. After 40 seconds the dosing pump
is reactivated.
After another 40 seconds the glow plug is deactivated and
20 seconds later the flame is checked. Detection of a
flame will cause the flame to be stabilised for
approximately 50 seconds by burning at 1.5 kW.
Should flame detection at that time be still negative, there
will be a run-down of the combustion and heating air fan
at full speed (approx. 5000 rpm) with an error lockout after
180 seconds.
After the first repeat start the heater enters an error
lockout condition. For error lockout reset the heater must
be switched off (at least for 2 seconds) and switched on
again.
NOTE
301