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The Neutral Density Filter allows you to verify that that the system operates within the ± 1% tolerance.
The purpose of this operation is to verify that your 6500 opacity meter is reading correctly. Each filter or
system comes with a document stating its value. If you have two filters, then you should have two separate
documents. If you order a replacement filter, ensure that you discard the old document. The document
declares the stated value for the filter in opacity, the max and min measurement values, and is signed and
dated from the factory.
There are two styles of filters: full flow and partial flow. The full flow filter is a 2” square piece of tinted glass.
To measure the full flow filter, place the filter flush up against the metal circular baffle plate and center the
glass over the hole that is emitting the green light. The partial flow filter is an aluminum bar with holes at
either end. One of the holes contains the filter. To measure the partial flow filter, fully insert the bar, glass
end first, into the small slot that is perpendicular to the channel where the smoke flows out of the top of the
head.
Start with the meter off, and the filter placed off to the side. Turn the meter on, and select the default setting
for stack size and horse power. When the meter displays “press start to begin test”, do not press start.
Instead, position the filter as described above. Once the filter is positioned properly, press start. The meter
will read the glass, then press save. Repeat this step three times. Next, press the compute average button.
This average is compared to the stated value on the document. If the average is within the specified range,
the meter is functioning properly and you can proceed to perform smoke measurements. If the average is
outside the specified range, do not perform test and call tech support to diagnose the problem.
APPENDIX B.
VERIFICATION WITH NEUTRAL DENSITY FILTER
