Webasto TSL 17 Coolant Heater
Webasto Product N.A., Inc. 9 www.webasto.us
Functional Description
Switch ON
Upon switching the heater on by the rocker switch or the optional timer, the ceramic igniter pin, the combustion air
fan and the circulation pump are activated. After 30 seconds the fuel metering (dosing) pump starts operation and
combustion air fan operation is suspended for 3 seconds.
Subsequently the combustion air fan speed is increased in two ramps within 56 seconds to nearly full load operation.
After a stabilization phase (constant speed) of 15 seconds the combustion air fan speed is again increased in a ramp
within 50 seconds to nearly full load.
After reaching full load fuel delivery, the ceramic igniter pin is deactivated and the combustion air fan operation is
increased to full load.
During the subsequent 45 seconds as well as in normal operation the ceramic igniter pin functions as a flame sensor to
monitor the flame condition.
Once all these events are completed, the heater begins the automatically controlled heating period of operation.
In case of a no flame condition or a flameout, a restart is automatically initiated. If the no flame condition persists, fuel
delivery is stopped and the heater enters an error lockout with a cool-down of the combustion air fan.
A flameout during normal combustion operation causes an automatic restart.
Heating Operation
When the temperature rises to reach 161° F (72° C) the heater switches to the energy saving part load operation.
A further rise in temperature up to 171° F (77° C) causes the heater to enter a control idle period. This also happens
when exceeding a total heating operating time of 76 minutes.
The circulation pump and the operation indicator light (if equipped) remain on during control idle.
After cool-down of the coolant to 160° F (71° C) the heater resumes part load operation. Another rise in temperature
to 171° F (77° C) causes the heater to enter again the control idle period. A drop in the coolant temperature during
part load operation due to an increased demand in heat will cause the heater to switch to full load operation at 133° F
(56° C).
Should the coolant temperature however not drop within 15 minutes during the control idle period to below 160° F
(71° C), a subsequent drop in the coolant temperature below 160° F (71° C) causes the heater to perform a regular
starting sequence into full load operation.
Switch Off
When turning the heater off the combustion process terminates and cool-down commences. The circulation pump
and the combustion air fan first continue operation to cool the heater down (cool-down) to be automatically switched
off afterwards.
NOTE
The cool-down time and the combustion air fan speed depend on the heater operating condition at the time of deactivation.
Cool-down time is 175 seconds when deactivated in full load operation and 100 seconds when deactivated in part load operation.
Dependent on the software variant implemented in the control unit there might be deviations from those cool-down periods.
Technical Data
To Next Page
Loading...
Need help?
General