9.2 Leak-Test Procedure
A quality assurance self-test feature allows DC-Lite users provided to verify
integrity of the flow cell. It is recommended that the self-check leakage test be con-
ducted periodically as part of an on-going quality assurance program.
Passing the leak test does not ensure proper function of the DC-Lite. It does
ensure that total leakage is within the product’s allowable limits. To ensure proper
function of the DC-Lite annual factory calibration is recommended.
To Initiate the Leak-Test
The leak-test tubing accessory is a short piece of latex with a red plug. It is found
in the tubing kit shipped with your DC-Lite. Place the leak-test accessory over the
inlet port (top port).
If at any time the unit fails the leak test, the display will read “Maintenance Reqd
Push Read.” Try the test again, and if necessary, call Bios for technical assistance.
1
If the DC-Lite is turned off, press and hold the
Stop
button, then press the
On
button. If the DC-Lite is already turned on, then press and hold the
Stop
button while also pressing the white recessed
Hard Reset
button on the back
of the DC-Lite.
2
The display will read “Leak Test, Invert & Push Read.” If it does not say this,
follow the previous instructions again, or call Bios for technical assistance.
3
Invert the DC-Lite so that the piston moves to the top of the cell, which is now
facing downwards. Press the
Read
button to close the internal valve.
4
Return the unit to an upright position, make sure that the piston is beginning
at the top of the cell, and place the DC-Lite on a flat, vibration-free surface.
5
As the piston falls from the top of the cell, its descent is timed. This may take
as long as 15–20 minutes. Note that the piston may not fall to the bottom of
the cell, and may not move far at all.
6
If completed successfully, the display will read “Test OK Press Read.”
7
Press the
Read
button and the internal valve will open, allowing the piston to
fall any remaining distance to the very bottom of the cell.
8
Repeat this test with the leak-test accessory connected to the outlet port
(lower port).
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8.3 Calibrating Rotameters
When calibrating rotameters the DryCal DC-Lite should be used as a transfer
standard only. Do not use the DC-Lite in line with a rotameter. For optimum accu-
racy, use a rotameter over its mid-range.
1
Attach an isolating restriction or sample medium, with a pressure drop of
about 8–12 inches of water column, in line with a stable sampling pump and
a DryCal.
2
Calibrate the sampling pump at the desired flow setting (ie: 2.0 L/min)
with the DryCal. When the desired flow setting is obtained, disconnect the
DryCal and attach the tubing to the outlet port of the rotameter.
3
When the rotameter ball stabilizes, mark the rotameter for the true flow
rate (2.0 L/min for example) using tape and a permanent marker to denote
the calibrated flow setting or note the point on a rotameter flow chart.
Repeat this procedure for any additional flow settings.
8.4 Use with Magnehelic Manometers
High-capacitance spring-loaded gauges such as Magnehelic manometers can
cause vibration of the DryCal piston. This is not a defect in the DryCal. The piston is
accurately mirroring the transient internal vibrations of the gauge. This type of
gauge must be isolated from the DryCal by inserting a suitable restriction between
the gauge and the calibrator.
9.0 Maintenance, Quality Assurance
Although the DryCal DC-Lite is a rugged instrument, certain care and maintenance
requirements must still be met.
Current service and calibration information and pricing can be found at
www.drycal.com/service/dclite.htm.
9.1 Maintenance
When not in use always store your DC-Lite in a clean, dry environment. When
possible leave the unit on charge. Wipe only with a damp cloth and do not spray
with liquid solvents or use abrasive cleaners.
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