MKS HPS 945 Series, Operation And Maintenance Manual

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22
Digital Pirani vacuum Sensor System
Troubleshooting and Service
The Series 945 Pirani Controller is designed to be maintenance-free under
normal operation. If a problem should occur, the following chart lists
symptoms, possible causes, and their remedies. With this guide, you should
be able to diagnose some problems and correct them. Those which fall
outside the scope of this chart are generally not serviceable by the user, and
the unit should be returned to HPS
TM for repair.
Cleaning the Pirani Controller Front Panel
The front panel of the Pirani Controller is designed to resist many laboratory
solvents. The casing can be cleaned with water or alcohol.
Do not use acetone on the front panel.
Maintaining the
Series 945 Pirani System
Troubleshooting Chart
Pressure readings are too
high or too low.
No analog output voltage,
and no display.
No analog output voltage,
but set points functional.
Set point relay will not
operate.
Display shows "nc"
1. Contaminated Sensor.
2. Gas other than air is used.
3. Controller incorrectly calibrated.
1. Power supply turned off.
2. Fuse is blown.
3. Defective PC board.
1. Analog output shorted to ground.
2.
Accessory or Gauge connector
disconnected.
3. Defective PC board.
1. Set point voltage incorrectly set.
2. Broken or shorted Sensor filament.
3. Defective PC board.
1. Cable or sensor hot conheated
2. Fensor filament broken
1. Test and replace if necessary.
Refer to page 23.
2. Refer to page 20.
3. Refer to page 17.
1. Turn power on.
2. Replace fuse.
3. Return to HPS
®
for repair.
1. Check cable connections at
Accessory port.
2. Connect cable to its port.
3. Return to HPS
®
Products for repair.
1. Check set point.
2. Test and replace if necessary.
Refer to page 23.
3. Return to HPS
®
Products for repair.
1. Conneat properly (page 12)
2. Replace sensor (page 23)
Symptom Possible Cause Remedy