49
Figure 14
The location of the STB safety temperature limiter and temperature sensor
THERMAL PROTECTION
The boiler controller is equipped with the
safe temperature limiter STB protec-
ting
against boiler overheating (water boiling in the system) when the controller is
damaged. The safe temperature limiter is a mechanical protective device consisting
of a sensor (located near the supply terminal strip on the upper insulation cover),
operating according to a disconnecting contacts principle and cutting off the power
supply to the blower fan and the fuel feeder when the limit temperature is exceeded
(set within a range of 90 to 100°C). The equipment cannot be restarted automatically,
even when the temperature is lowered. The user must switch them on, resetting the
sensor (with the button) after the temperature of the boiler is reduced.
NOTE! An attempt to engage the “dislocated” sensor on the hot boiler can
cause damage to the STB safety temperature limiter.
When this sensor is damaged or overheated,
the fan and the feeder are discon-
nected
(do not work either in the manual or the automated mode), and the message
“Temperature too high”
is shown on the controller.
Dismantle the controller to replace the temperature sensor. Then push away
insulation of mineral wool; the temperature sensor is installed in the measuring
well The STB safety temperature limiter is installed in the upper cover on the sup-
ply terminal strip (Fig. 14)
temperature Sensor
STB
