To keep your control valves operating at optimal performance, physically inspect your valve at least every 12 weeks or so, assuming the system is running as intended. The visual inspection will allow you to check for any leaks in the tubing and review the pressure gauges to ensure the control valve is actually doing what it is supposed to do.
Most manufacturers have instruction manuals available on their websites to provide you with specific details for maintenance. To further support you, Singer Valves has created this simple Control Valve Service Matrix & Score Card, which will allow you to score the condition of your control valve and determine the action(s) that may need to be taken.
*Safety first! As a note of caution, these valves are under pressure and care should be taken to bleed pressure off the valve before you start to take any valves apart.