Troubleshooting Air Valve Failures
Troubleshooting Air Valve Failures
(OP)
We have been having an issue with a particular solenoid air valve failing only during machine start-up. This occurs whether the machine is down 5 minutes or 5 days. The valves fail in groups of 3-10 only upon start-up. When the machine is running these valves outlast the other brands we use. This has been a problem for years and nobody has answers. Any ideas would be greatly appreciated!
FYI the machines are for glass molding.
FYI the machines are for glass molding.





RE: Troubleshooting Air Valve Failures
Don
Kansas City
RE: Troubleshooting Air Valve Failures
The valves have intermittent duty coils, and the startup sequence leaves them on for too long, burning the weakest.
OR
The startup sequence cycles them too often, and the inrush current overheats them.
OR
Honestly, it could be anything else. One way to isolate problems like this is to look at the machine through a child's eyes. Try to explain to someone, even literally a child, what _should_ be going on, record that, and walk through it slowly, measuring what is _actually_ going on, and taking nothing for granted.
Okay, it would be easier with a lab full of fancy instrumentation, but get as close as you can with what you can scrounge up or improvise, and you might get lucky.
Mike Halloran
Pembroke Pines, FL, USA
RE: Troubleshooting Air Valve Failures
Good luck
Jamey
www.machinetoolhelp.com
RE: Troubleshooting Air Valve Failures
RE: Troubleshooting Air Valve Failures
RE: Troubleshooting Air Valve Failures
Does one brand of valve's solenoid have a built-in diode to prevent back-EMF from spiking contacts or controllers upstream and the the other brand doesn't?
RE: Troubleshooting Air Valve Failures
RE: Troubleshooting Air Valve Failures
Ed Danzer
www.danzcoinc.com
www.dehyds.com
RE: Troubleshooting Air Valve Failures
To me this indicates a mechanical failure more than an electrical one.
Suspicions to check in priority:
1. Oil lubrication (total check, all points as stated above, compatibillity of oil type to all sealings in solenoid). Not excessive oil, none or as little as possible. To much oil is a common problem.
2. Dirt and water. Smudge and water filters to be installed, if not present, on low-point before solenoid valves, even if all parties swear the air is clean (this is in 80% of all cases not true enough)
3. Trotteling of devices or dimensions in and out? Dust or smudge covered silencers not giving sufficient delta P in and out?
4. Air pressure above allowable or possibly higher when starting than by normal running? Measure at solenoid point! In case solenoid to weak?
5. Electrical a) Correct voltage (sufficient force) reaching solenoid? Measure!
6. Electrical b) Pilot plunger sticking by permanent magnetism by wrongly selected material combination?
1 and 2 will cover about 60-80% of all failure causes.
RE: Troubleshooting Air Valve Failures
You may be getting some electrical spikes that are messing things up...
RE: Troubleshooting Air Valve Failures
Ted