Series 830/840/860 Instruction Manual | Chapter 5 Troubleshooting |
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Flow Controllers with Motor-operated Rotary Valves
Problem | Possible Cause | Solution |
Valve “hunts” back and forth | Pressure differential too great | Reduce pressure |
continuously | Motor coupling set screws loose | Tighten set screws |
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| Valve motor failure | Replace motor |
Valve rotates continuously | Limit switch out of adjustment or bro- | Adjust or replace switch |
| ken |
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| Microprocessor failed | Replace microprocessor |
Valve does not rotate | Contaminant blocking valve | Remove blockage |
| Motor fuse blown | Replace 1 amp fast blow fuse on |
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| motor valve board |
Flow reading is erratic | Inlet filter screen clogged | Clean or replace screen |
Reads full scale with no flow or | Defective sensor | Return to factory for replacement |
with valve shut | Q1 shorted | Replace with same type part |
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| U10 failed | Replace with same type part |
Flow does not match set point | Insufficient pressure differential | Increase pressure or reduce set |
within specifications |
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