Spheros thermo 231, Workshop Manual

Page: 36 / 98

6 Functional Checkouts Thermo 230 / 231 / 300 / 301 / 350
602
6.3 Components Testing
6.3.1 Temperature Sensor Resistance
Check
When checking the temperature sensor with a digital
multimeter the values of the following diagram must be
obtained. Resistance checking is preferably performed at
ambient temperatures between 20° C and approximately
100° C (immerse sensor in water).
6.3.2 Flame Sensor Resistance Check
NOTE
The glass bulb of the flame sensor and the viewing glass
of the window (refer to Fig.) are to be cleaned if contami-
nated. In case of damage or not obtaining the rated values
replace flame sensor.
Check
– cover flame sensor glass bulb
– check resistance (rated value: < 20 kOhm)
– uncover flame sensor glass bulb and expose to light
of strong lamp.
– check resistance (rated value: < 400 Ohm)
6.3.3 Igniter Electrodes Check
NOTE
The insulator of the igniter electrodes must show no
damage. Igniter electrodes not working properly must be
replaced.
Check
– inspect insulators of igniter electrodes for damage
Water temperature °C
R
esis
tan
ce
(Oh
m
)
100 50 10
1000
5000
10000
R/y
T/°C
20 °C
≅
4419 ..... 4892
W
100 °C
≅
319 ..... 348
W
Viewing glass
Glass bulb