Ion Science MVI - Manual (Page 20)

MVI MANUAL Ion Science Ltd
Page 20 of 23
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User maintenance
Alarm Level
The Mercury alarm level is factory set at 20 µg/m
3
. These values are limited by unit accuracy. The alarm
level cannot be set beyond 35 µg per metre cube.
MVI Health Check
Over time the internal filter and tubing can become contaminated. We, therefore, recommend carrying out
an occasional health check to ensure that the instrument is clean and not giving slow or false readings.
There are 4 simple tests as detailed below which can be carried out by the user.
Prior to testing switch on the MVI and select the 2000 range. Leave the instrument to stabilise for 10
minutes before proceeding.
Test 1:
Can the MVI be zeroed?
Zero the MVI in clean air (do not use the charcoal filter). Can the MVI be zeroed? If not, then a
service is required. If yes, then continue.
Test 2:
Check for internal contamination
Using a clean piece of flat card or plastic, block the air flow to the luer connector. This will force
air to be drawn from the internal parts and any contamination will show on the display. If the
reading increases by a value greater that 5 ug/m
3
then the MVI internal parts are contaminated
and service is required.
Test 3:
Check for case contamination
Use a clean, dry cotton bud and scrub the lid top where dirty. Offer the bud to the luer inlet and
note any reading changes. A change of greater than 5 ug/m
3
indicates the case requires some
cleaning.
Test 4: Does the MVI detect Mercury?
Obtain a sample of mercury and offer this to the inlet. Check that the MVI responds accordingly.
If the instrument does not detect any Mercury then the MVI will require servicing.