Mixing Station Angle Seat Valves Troubleshooting

Mixing Station Angle Seat Valves Troubleshooting

Issue: Mixing Valve won't open/close properly

Common Troubleshooting Tips:

1. Check Wiring
      Refer to Electrical Schematic
      Check for loose wires, incorrect terminal locations, blown fuse, faulty PLC output
      Check 24VDC, continuity using a multimeter

2. Check Air Supply Pressure (80-90 psi)
      Also check for leaks/hissing at the valve control head.

3. Run Self-Calibration procedure
      Refer to Digital Positioner user manual "8049-4 4-Wire Positioner Manual" Page 40 for instructions
      Check status (green) & error (red) lights inside Digital Positioner, refer to Page 42 of user manual or "Status & Error Lights" attachment for fault messages
      Refer to Page 43 for full Digital Positioner troubleshooting tips 

      For newer version of the Digital Positioner with LED screen (replaces simple status and error lights), refer to pages 40-42 of "8049-4_-Manual 2022 Version" attachment for similar information.

4. Run Mixing Valve in Manual Override Mode
      Refer to user manual Page 37 for instructions
      If either the IN or OUT commands don't work properly then it is likely a faulty internal solenoid valve

5. Make sure Sensing Pin inside Digital Positioner is tight

Here are some instructions for adjusting the sensing pin of the digital positioner. Please see attached video ("Digital Positioner.MOV") and photos for reference. 

  1. Power down the control panel
  2. Disconnect valve wires inside the black control head (take a picture to remember their exact locations for later)
  3. Remove the control head
  4. Place the control head on a work table with the top of the actuator pointing upwards to the ceiling
  5. Open the control head
  6. Carefully slide the circuit board up to reveal the sensing pin/spring
  7. Push the plunger from the bottom of the sensing pin so it is at its maximum travel and hold that position
  8. Tighten the set screw on this pin clockwise with a small flathead screwdriver
  9. Once tightened, let go of the plunger to allow the pin to spring return to its neutral position
  10. Replace the circuit board into its original position
  11. Reinstall the control head into the valve
  12. Reattach the control wires

6. Check Solenoid Valves internal to Digital Positioner
      Black/brown marks on body of solenoid valve would indicate a short circuit
      Check for rust at the air connections
      Replace solenoid valves if required

7. Check for damage on Circuit Board Inside Digital Positioner  
      Check for obvious signs of short circuits, lack of power, etc.
      Replace entire Digital Positioner if required