Spheros Thermo S 160, Workshop Manual

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m r e h T s n o i t c n u f r e t a e H 4 o S 160/230/300/350/400
402
4.2 Operational heater sequence
4.2.1 Switching on and start
When switched on, the operating display is illuminated,
the control unit starts controlled operation and checks the
coolant temperature.
If the coolant temperature is below the upper temperature
threshold, the initial cycle starts.
Combustion air fan and circulating pump are switched on.
After approx. 12 seconds (initial cycle time) the high-
voltage spark is ignited. Approx. 1 second later the
solenoid valve in the fuel pump is opened.
The fuel injected via the atomizer nozzle and mixed with
the air of the combustion air fan, is ignited by the ignition
spark and burned in the combustion chamber.
The flame is monitored by a flame detector integrated into
the control unit.
A few seconds after a flame is detected, the control unit
switches the electronic ignition unit off. Until then the
flame is stabilised. The heater is not yet in heating mode.
With optional nozzle block preheater:
The integrated temperature sensor determines the
temperature on the nozzle holder as soon as the initial
cycle starts. Starting at a temperature of < 5°C the nozzle
block preheater is switched on. Depending on the
determined temperature and the vehicle electrical system
voltage the preheating time is determined. The duty cycle
is limited to a maximum of 120 seconds.
The burner motor does not run during the entire
preheating time. It starts latest 12 seconds prior to
expiration of the determined preheating time during initial
cycle.
The initial cycle time can be extended to a maximum of
120 seconds.
The further sequence takes place as described.
4.2.2 Heating operation
After the flame is stabilised, the heater is in controlled
(normal) operation.
Depending on the coolant temperature, the coolant
temperature is maintained at one level by switching the
burner alternately on and off.
Once the upper switching threshold is exceeded, heating
operation is finished and run-down initiated.
The solenoid valve is closed, the flame expires, however the
combustion air fan and circulating pump continue running.
The run-down ends approx. after 120 seconds. The
combustion air fan is switched off.
The heater is in a controlled break.
The operating disp lay is illuminated.
Fig. 403 Operational sequence
Signals
Main switch off on off
Terminal 61 ) g n i t a e h g n i k r a p ( f f o ) g n i t a e h y r a i l i x u a ( n o ) g n i t a e h g n i k r a p ( f f o
n i m _ T < T x a m _ T = > T n i m _ T < T x a m _ T = > T n i m _ T < T n i m _ T > T e r u t a r e p m e t t n a l o o C
UPFA o
n
UPFA o
ff
Flame
ge
n
e
ra
ti
o
n
Flame
g
e
neration Flame
g
e
neration
Actuators
Operating display
Flame display
Combustion air motor
Circulating pump
Electronic ignition unit
Solenoid valve
Nozzle block preheater
Time in s 0..108 12 1 0..15 5 ... 30 90 0..108 12 1 0..15 5 ... 30 90 0..108 12 1 0..15 5 ... 30 90
State
Look for Op
tion
al n
o
zz
le
bl
ock
pr
ehea
ting
Init
ial c
ycl
e with li
g
h
t check
Pr
e-
ign
iti
o
n
Igni
tio
n
Stab
il
is
a
ti
on
Run-
down
with
sa
fety
perio
d
Run-down
2
Op
tion
al n
o
zz
le
bl
ock
pr
ehea
ting
Init
ial c
ycl
e with li
g
h
t check
Pr
e-
ign
iti
o
n
Igni
tio
n
Stab
il
is
a
ti
on
Run-
down
with
sa
fety
perio
d
Run-down
2
Op
tion
al n
o
zz
le
bl
ock
pr
ehea
ting
Init
ial c
ycl
e with li
g
h
t check
Pr
e-
ign
iti
o
n
Igni
tio
n
Stab
il
is
a
ti
on
Run-
down
with
sa
fety
perio
d
Run-down
2
OFF Standby Start Heating Run-
down
Standby Start Heating Run-
down
Standby Start Heating Run-
down
Off