I need help trying to increase the output of a pneumatic 12810 Masoneilan level controller from its current output of about 14psi to 20psi. I have adjusted the proportional band, reset rate knob. I've also ensured that the nozzle is clean. The input pressure exceeds 20 psi and the pilot (from what I've been told) is new. So my question is what else can I do to try to increase the output pressure?

Thanks in advance for any help and suggestions.

 

Note that the unanswered post above is from 2015 (7 years ago) and has undoubtably been resolved by now. I stumbled onto it when searching for other Masoneilon pneumatic controller info and the question intrigued me. I have almost no experience in pneumatics, other than troubleshooting 62VA differential relays used in bubblers or trimming 3-15psi I/P tranducers because I came into the field when uP's were displacing discrete electronics, which by then had largely displaced pneumatics. But where and how control is accomplished applies to pneumatics as well as electronics.

The 12810 is a proportional-reset pneumatic level controller using torque tube technology.

A typical installation, with the separate control valve is shown in the diagram below:


The manual for the 12800 pneumatic level controller series says this about the pneumatic air supply:



Clearly, the 12800 series is a classic pneumatic controller. The 12810 is specifically a proportional-reset controller designed for either a 3-15PSI control output or a 6-30 PSI control output. Although the manual mentions kits for conversion from one control mode to another, there is no mention of converting the relay from 3-15psi to 6-30psi or vice versa, so I assume the relay is part of the model number as ordered.

The inability of the controller to produce more than "about 14 psi" is likely due to
a) the controller is supplied with a 3-15PSI control output relay, not a 6-30PSI control output relay
b) the 3-15PSI output being maxed out
c) the output pressure gauge being slightly out of calibration, indicating 14 instead of 15 psi

If more force is needed to move the actuator on the control valve, then the solution is the use of pneumatic positioner to provide air pressure to the valve’s actuator because a positioner is designed to supply more than the 3-15 control signal’s maximum 15 psi to the actuator.