Technical User Guide
6
DOL 51
LED indication
Sensor status
Action
GREEN flashing
quickly
Concentration measurement is
above 52.5 ppm, outside the mea-
suring range.
Ventilate with fresh air.
GREEN/GREEN/
GREEN/YELLOW
Age monitoring, sensor element is
older than 1½ years, service life is
expired; see date on sensor ele-
ment type plate.
Replace the sensor element.
YELLOW/YELLOW/
YELLOW/GREEN
Heating defective.
Replace the DOL 51 housing.
7 Trouble shooting instructions
Error
Cause
Action
Packaging is damaged.
Damage in transit.
Contact the supplier in case the sensor
element is damaged.
No measurement on the control
unit.
Electrical connection faulty or in-
terrupted.
Check installation for cable break.
DOL 5
1
aligned incorrectly, not
vertical.
Install the sensor in accordance with
mounting instructions, ve/- 15°.
Sensor element is faulty or used
up.
Replace the sensor element.
DOL 51 housing is defective.
Replace the DOL 51 housing.
Incorrect measurement on the
control unit.
The dust filter is clogged.
Replace the dust filter.
Check the sensitivity with test gas.
Unexpected measurement on
the control unit.
Brief interference pulses <5 sec-
onds.
Interference caused by electrical equip-
ment, e.g. lighting, fans or heaters. Iden-
tify device and suppress interference.
Unstable measured value.
Dynamic signal fluctuations with
a period of more than 5 seconds
can arise from turbulence with
fresh air.
Not activity, continue to monitor.
Wet sensor.
The sensor was cleaned with
water.
Wipe the sensor dry.
Condensation.
Black fluid is leaking from the
sensor element.
The sensor element is defective. Replace the sensor element.
No heat in the convection cap.
Heating defective. Possibly due
to a faulty cable between DOL
51 housing and the convection
cap.
Replace the DOL 51 housing.
8 Maintenance
The sensor element must be replaced after 1½ years of operation at the latest, see date on the sensor element
type plate.
Carry out the daily visual inspection to see if the sensor is ready for operation.
