Webasto Thermo Top C - PME Service Manual download pdf (Page 12)

Thermo Top E and Z/C 3 Functional Description

3 Functional Description

3.1 Functional Description Thermo Top Z

(Supplementary Heater)

3.1.1 Switch On / Starting

Fuel

When starting the vehicle engine the heater goes in

standby. With a water circuit temperature below 60° C and

an outside temperature below 5° C (option with outside

temperature sensor) the starting sequence commences.

The glow plug and the combustion air fan are activated.

After 30 seconds the fuel dosing pump starts operation

and combustion air fan operation is suspended for

3 seconds. Subsequently the combustion air fan speed is

increased in a ramp within 57 seconds to nearly full load

operation.

After reaching full load fuel delivery within this period the

glow plug is deactivated and the combustion air fan

operation increased to full load.

During the subsequent 45 seconds as well as in normal

operation the glow plug functions as flame sensor to

monitor the flame condition.

After all these events the automatically controlled heating

operation starts. 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 heaters

enters an error lockout with a run-down of the combustion

air fan.

Diesel

When starting the vehicle engine the heater goes in

standby. With a water circuit temperature below 60° C and

an outside temperature below 5° C (option with outside

temperature sensor) the starting sequence commences.

The glow plug and the combustion air fan are activated.

After 30 seconds the fuel 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 stabilisation 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 glow plug is

deactivated and the combustion air fan operation

increased to full load.

During the subsequent 45 seconds as well as in normal

operation the glow plug functions as flame sensor to

monitor the flame condition.

After all these events the automatically controlled heating

operation starts. 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 run-down of the combustion

air fan.

A flameout during normal combustion operation causes

an automatic restart.

3.1.2 Heating Operation

Fuel

When the temperature rises to reach 72° C the heater

switches to the energy saving part load operation. A rise

in temperature up to 76.5° C causes the heater to enter a

control idle period. This also happens when exceeding a

total heating operating time of 76 minutes.

After cool-down of the coolant to 71° C the heater

resumes part load operation. Another rise in temperature

to 76.5° 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 56° C.

Diesel

Heating operation for the Diesel type heater is identical in

the sequence of events. Should the coolant temperature

drop during the control idle period to but not below 71° C

within 900 seconds, a subsequent drop in the coolant

temperature below 71° C causes the heater to perform a

regular starting sequence into full load operation.

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 65° C.

3.1.3 Switch Off / Deactivation

When turning the engine off the heater is deactivated.

Combustion stops and run-down commences. The

combustion air fan first continues operation to cool the

heater down (run-down) to be automatically switched off

afterwards.

NOTE

The run-down time and the combustion air fan speed

depend on the heater operating condition at the time of

deactivation.

Run-down time is for:

Fuel

168 seconds when deactivated in full load operation and

157 seconds when deactivated in part load operation.

Diesel

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 run-down

periods.

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 45 46

Comments to this Manuals

No comments

Webasto Thermo Top C - PME Service Manual Page 12

Comments to this Manuals

Related products and manuals for Water heaters & boilers Webasto Thermo Top C - PME