TROUBLESHOOTING AND MAINTENANCE
Troubleshooting Guide
Symptom
Velometer not at zero
(before use).
Reading not the same from
range to range.
Readings are low.
No readings.
Negative readings.
Correction
1. Velometer not adjusted. See zero
adjustment method, page 3.
2. Assembled probe and meter accidentally
reading pressure or aiflow. Check
adjustment with caps on sensing ports.
3. If Velometer does not remain at zero in all
positions, it should be returned to the factory
for calibration.
1. Different probes being used. The same
probe should be used on both ranges.
2. Wrong probe being used. See pages 7–9
for correct application.
3. Measurement technique is different. Hold
probe in the same way, and at the same
place in the air flow, on all ranges.
4. Different Range Selector in use. Be sure
that both Range Selectors are in operating
condition: O-rings not worn, filters clean.
5. Range Selector switch not in operating
position. Switch plate must be at either
extreme of its travel.
1. Verify that the proper probe is being used.
2. Check for leaks in the O-rings on sensing
ports, Range Selector and probe. Replace
if necessary.
3. Filter in the Range Selector needs to be
cleaned.
4. Wrong scale is being read, or Range Selector
switch not set properly.
5. Hoses are not 24 in. long. Do not use hoses
that are different (longer or shorter) than
those originally provided with the Velometer.
1. Air flow is being blocked by operator's hands.
2. Hand on the switch button of Range Selector.
(See page 4.)
3. Hoses or probe not connected.
1. Probe not being used properly. (See section
of manual describing use of specific probes.)
2. Hose connections must be reversed, either at
the Range Selector or at the meter.
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