MKS Mass-Flo 2179A - Chapter Seven: Troubleshooting; Troubleshooting Chart

Chapter Seven: Troubleshooting Troubleshootin
g
Chart
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Chapter Seven: Troubleshooting
Troubleshooting Chart
Symptoms Possible Cause Remedy
No output or overrange at
zero (after warm-up)
Improper cable
Valve override function
applied
Electronics malfunctioning
Check cable for type
Disconnect valve override
Return for service
Unit indicates a negative flow Unit installed in gas stream
backwards
Reinstall unit in proper flow
direction
Controller does not track set
point
Improper zero adjustment Zero meter output, according
to
How To Zero the Flow
Controller,
page 40.
Controller does not function Electronics malfunctioning
Valve sticking
Return for service
Readjust the valve, following
the instructions in
How To
Adjust the Valve Preload,
page 50
.
Oscillation Too high a controller gain
setting
Incorrect upstream pressure
regulator
Upstream pressure too high
Reduce (turn counter-
clockwise)
Check manufacturers’
specifications
Reduce upstream pressure
Excessive closed conductance Inadequate valve preload Readjust the valve, according
to
How To Adjust the Valve
Preload,
page 50
.
Unit does not achieve full
flow
Upstream pressure too low
Excessive valve preload
Increase upstream pressure
Readjust the valve, according
to
How To Adjust the Valve
Preload,
page 50
.
Table 9: Troubleshooting Chart