PN 9000-133-VE, Rev U
Flow Sensor Alarm Limits Checks
The flow sensor reports flow as relative to ideal (i.e., 100 % is ideal flow, 50 %
is half of flow). An alarm is generated when the sample flow is less than 45 %
ideal.
The flow measurement is directional, with reverse flow generating an alarm.
Problem/Possible Cause
Corrective Action
Flow Sensor Failure alarm
generated
One or both of the two resistive elements within the Flow Sensor
has failed (open). Each element should be approximately 8–10 Ω.
Note:
A Flow Sensor failed alarm will be generated if either element
is Open.
To measure the resistive elements:
1. Take all necessary safety precautions and power down the
WDG-V Analyzer.
2. Measure the resistance of each element (Flow Heater, Flow
Sensor) at the terminals inside the electronics enclosure.
3. If resistance is much lower or higher than 8–10 Ω, replace
the Flow Sensor.
Flow Sensor Heater Element (Red Wire)
Flow Sensor Sense Element (Yellow Wire)
Figure 3-1.
RTD Flow Sensor.
3-10 | Thermox
®
WDG-V / VC / VCM / VM
Summary of Contents for WDG-V
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