Parker solenoids with pilot solenoids

[RANGER1]

Interestingly the last few months I have seen issues with "worn" solenoids.
Both on liquid makeup to vessels, which take longer than normal, or no longer can keep up to make required level.
Mid you manually jack open solenoid, no worries.
Appears main piston wears in bore of valve, pilot solenoid cannot vent enough of top of piston to open it fully.
Mother brands have a seal on main piston, so not as much of a problem.
Anyone experienced similar symptoms?

[Grizzly]

Hi Ranger.
I have had similar with old Danfoss PM valves.
But now they are obsolete, not so often.
I don't have many Parker ones on my patch, so I cannot comment.
I had a solenoid coil on a Sabroe Screw Loading Gear buzzing badly, only 2 days ago.

Which was picked up by my colleague the ex apprentice.
He heard it before me when we walked into the plant room. The benefit of Young Ears I guess?
Anyway it was red hot compared to the others!
So we changed it, Buzzing stopped and smooth operation was regained.
Good shout though Ranger, coils of all sorts loose efficiency.
Some with more drastic consequences than others.
Grizzly

[Magoo]

Hi Ranger.
Have similar issues with Danfoss PMFL fill valves, a piston service kit will extend life for a period, the barrel wear requires total replacement after that. You will be familiar with the plants.

[RANGER1]

Hi Ranger.
Have similar issues with Danfoss PMFL fill valves, a piston service kit will extend life for a period, the barrel wear requires total replacement after that. You will be familiar with the plants.

A Witt float would have been good for those plants, with pipe in bottom of receiver so t/siphon always has liquid level.

[PaulZ]

Hi Ranger
Parker valves do wear a lot. I the past we used to put kits in them only to find a few weeks or months later some of the valves had the same problem. This would be a call back and in the end replaced with a new valve, had arguments with clients as to who would pay.
If we come across a Parker solenoid leaking S8F, S7A, S4A we will replace the whole valve, no call backs and the price works out about the same when you add in parts and labour. Same goes for suction valves, pretty much any pilot operated Parker valve.
Hansen are very similar and we do the same with them.
Regards
Paul

[RANGER1]

Hi Ranger
Parker valves do wear a lot. I the past we used to put kits in them only to find a few weeks or months later some of the valves had the same problem. This would be a call back and in the end replaced with a new valve, had arguments with clients as to who would pay.
If we come across a Parker solenoid leaking S8F, S7A, S4A we will replace the whole valve, no call backs and the price works out about the same when you add in parts and labour. Same goes for suction valves, pretty much any pilot operated Parker valve.
Hansen are very similar and we do the same with them.
Regards
Paul

Paul, totally agree, as in some cases with A4A, S5A etc you can't get apart without trouble because of rusty bolts.
All is well if you can get a new one, as more available these days, as well as interchangeability with Hansen.
I alway remove all bolts with new/old & use anti-seize.
The most interesting thing to me was valve would not fully open in the case of worn piston/bore.

[cricri]

Hi ranger,
The piston is probably rotating in the valve. There is an expansion of the refrigerant in the solenoid as the downstream control valve is too opened.