Troubleshooting Pneumatically Actuated Valves

Fault Finding in Pneumatically Actuated Valves is a relatively straight forward process especially when compated to eletrically actuated valves. Pneuamtic Actuation falls under two main categories; Double Acting (air open/air close) and Spring Return (air open/spring close or vice versa). For most valve actuation a 90 degree turn rack and pinion pneumatic actuator.
This is what our fault finding below will cover.

Double Acting Pneumatic

Problem

Solution

Valve does not open or close

Check system air pilot pressure is above minimum actuator operating pressure (usually 6 Bar/ 90psi)

If air pilot solenoid valve fitted then operate manual override on pilot solenoid valve to check function.

With butterfly valves check that the valve is aligned with the flanges and not binding.

If ok make sure power is applied (LED).

Check that coil voltages are correct for supply (moulded on coil) and valve label complies.

Check coil is not `open circuit’ – use multi meter.

Valve leaks slightly when first commissioned

Strip and clean valve seat and re-test.

Adjust actuator stops if necessary to fully close valve.


Spring Return Pneumatic

Problem

Solution

Valve does not open

Check system air pilot pressure is above minimum actuator operating pressure (usually 6 Bar/ 90psi)
If air pilot solenoid valve fitted then operate manual override on pilot solenoid valve to check function.
With butterfly valves check that the valve is aligned with the flanges and not binding.
If ok make sure power is applied (LED).
Check that coil voltages is correct for supply (moulded on coil) and valve label complies.
Check coil is not `open circuit’ – use multi meter.
If necessary remove actuator and use spanner on valve to check if binding or jammed.

Valve leaks slightly when first commissioned

Strip and clean valve seat and re-test.
Adjust actuator stops if necessary to fully close valve.