Casella CEL Microdust 880 IS real time dust monitor - Manual (Page 45)

Microdust 880nm & WinDust Application Software
Handbook HB3255-03
Page 45 of 51
Fault finding tips
The Microdust contains no user serviceable components. Repairs should only be performed by
authorised personnel. Failure to comply with this will render the Intrinsic safety certificate null
and void.
If there is an electrical fault in the instrument it must be returned to Casella Ltd to repair.
Fault Symptoms Possible Cause Service hint
Instrument does not
switch on Battery discharged, or failing to
charge. Confirm charger
indicator lights. Recharge or replace battery if
necessary. Check charger output
=80mA.
Probe always reads
zero Fault with Infrared transmitter or
receiver. Span control is turned
fully anti-clockwise. Return to service department for
repair.
Continuous ‘over
range’ indication Optical misalignment due to
mechanical shock.
Excessive contamination. Return to service department for
optical alignment, cleaning and
calibration.
Unstable or drifting
zero setting with probe
cover on. Sample chamber may contain
dust or fibre. Use the hand pump to purge the
probe with clean air prior to
adjustment of the zero control.
The probe cover should be open
slightly when purging to allow
venting of purge air. (Purging is
especially important if using the
0-2 or 0-20 mg/m
3
ranges)
Unable to zero
instrument display Excessive contamination of
probe or optical misalignment
due to mechanical shock. Purge the probe with clean air
from the hand pump. If fault
remains, return to the service
department for optical alignment
and calibration.