Glacially Slow Valken HPA Regulator Recovery

[imadunatic]

After trying to find the root cause of my odd spike in first couple shots out of my HPA bench bottle, I've realized that my regulator takes AGES to recover. Like first shot is 700 psi, next shot is 675 (likely due to plenum and hose volume) and then the pressure drops down to about 550 psi over the next couple shots and then just sets there for pretty much ever, as in upwards of 5 minutes.

Is there any handy way to fix this? Is something inside in need of lube or a good rub down? I hate to waste 48ci of 3000 PSI air so it's going to wait until the next time I shoot the bottle to 600 PSI, but I'm hoping someone else has ran into this and has a fix.

Also, this pretty much negates my post about CO2 and HPA in my QB and makes the case look even better for HPA, only the first couple shots were actually at 700 PSI, and they were in the 14 FPE range..... Wouldn't hurt my feelings if every shot was in the 14 fpe range. That is just about perfect for my .177 plinker.

[vigilandy]

Not sure how the Valken is different in design from Ninja,  but it might be a good place to start investigating.  Ninja has a good rep for fast recharges and I don't think I've ever seen a post reporting this problemn with their regs.   I've got four three SHP and two standard models in service and they they work fine even in the RWS 850 repeaters. 

[imadunatic]

My 13ci bottles are definitely going to be Ninja's... The only real reason I ended up with the Valken is because it's what my local paintball shop carries, and sometimes it's nice to just grab something off the shelf, already full of air and go home. LOL.

That decision is going to cost me more work I think....

[Motorhead]

Sounds like a corrosion / lack of lube issue causing spool to stick.
Sadly have to DUMP the tanks contents to ZERO and remove regulator bonnet to extract spool and get some lube onto o-rings while making sure there is NO corrosion inside the regs mechanics.

JMO ...

[imadunatic]

Sounds like a corrosion / lack of lube issue causing spool to stick.
Sadly have to DUMP the tanks contents to ZERO and remove regulator bonnet to extract spool and get some lube onto o-rings while making sure there is NO corrosion inside the regs mechanics.

JMO ...

Thanks Scott. Next time I shoot it down I'll just finish bleeding it to zero and pull it apart. What do you use for lube? Divers silicone grease?

[Motorhead]

Sounds like a corrosion / lack of lube issue causing spool to stick.
Sadly have to DUMP the tanks contents to ZERO and remove regulator bonnet to extract spool and get some lube onto o-rings while making sure there is NO corrosion inside the regs mechanics.

JMO ...

Thanks Scott. Next time I shoot it down I'll just finish bleeding it to zero and pull it apart. What do you use for lube? Divers silicone grease?

When I service Regulators use a lube that is far superior to silicone which is actually a lousy lubricant IMO.
I use KRYTOX or ULTIMOX 226 after all the factory lubes have been thoroughly cleaned / removed.

[nervoustrigger]

This behavior is generally regarded as regulator creep as opposed to slow recovery.  It's all relative I suppose, but I would consider slow recovery to be 15 seconds, not 5 minutes.  My money is on a worn or poorly-fitting seat, or perhaps an inherent weakness of the particular regulator design.  Most paintball regulators I've tested exhibit a greater degree of creep than Ninja's "ball against a cone" design.  So it may be worthwhile to pull it apart and clean, inspect and reassemble but don't be surprised if the problem persists.

[imadunatic]

Jason,

More scientific test last night showed that if allowed to recover between every shot (on a full tank), recovery was actually closer to 15 seconds; once I have it apart I'll document what the guts of the Valken reg's look like for future tinkerer's.

This was just a band aid until I have time/money to get the 13ci bottles mounted up; after that it probably won't see much use. Would still be nice to mitigate this for those times when I need a bench bottle.

[nervoustrigger]

Okay, I'm curious now.  You are seeing it recover in about 15 seconds to X pressure, but does it continue to climb if you wait?  Say, after 2 minutes or 5 minutes?
 
Based on the symptom in your original post (first shot or two being fast after some idle time), it sounds very much like a classic case of the pressure creeping up because the valve seat is not sealing properly.
 
And by the way, that would also mean you have too much hammer strike and are wasting air.  Meaning there's enough hammer energy to open the valve with authority, despite the higher pressure acting against it.  When the hammer strike is adjusted optimally for your chosen regulator setpoint, the velocity would tend to either be slower or about the same when the pressure creeps up.

[imadunatic]

Okay, I'm curious now.  You are seeing it recover in about 15 seconds to X pressure, but does it continue to climb if you wait?  Say, after 2 minutes or 5 minutes?
 
Based on the symptom in your original post (first shot or two being fast after some idle time), it sounds very much like a classic case of the pressure creeping up because the valve seat is not sealing properly.
 
And by the way, that would also mean you have too much hammer strike and are wasting air.  Meaning there's enough hammer energy to open the valve with authority, despite the higher pressure acting against it.  When the hammer strike is adjusted optimally for your chosen regulator setpoint, the velocity would tend to either be slower or about the same when the pressure creeps up.

Jason,

It doesn't creep after it hits 700 PSI, that seems to be a fairly stable wall. When first pressurized from zero, it will bump right up to 700 PSI, and the velocity of my first two shots will be somewhat higher, I've chalked this up to some residual CO2 hanging out somewhere, but honestly, I've never fully tracked it down so I'm really just grasping at straws for those higher FPS first shots.

 Also, I haven't fitted a SSG to the QB78 yet, so I'm certain at this pressure, the hammer strike is way too much. I only plan on this being an 850 psi gun (I'm making 13 FPE with 700 PSI, I just don't need much more for plinking), so I'll need to fit an SSG (or possibly the twin spring...? Watching that one currently).

Without tearing into it, it's anyone's guess I'm thinking. I could have swore I read a post of yours where you swapped out internals in another brand (JDS I think?) of regulator with a ninja piston, but I can't for the life of me find it. Seems like you had similar symptoms with that one. I didn't bookmark, and so it's gone into the wind for now...

Kevin

[Motorhead]

Just to set an understanding on TERMS ....

CREEP is when a regulator get to the set point pressure ( Normally quickly ) them upon non cycling the pressure continues to rise as pressure BLEEDS PAST THE SEAT.

STICK is when the regulators internal spool DOES NOT react to the pressure change on its LP side when a shot taken.
When spools sticky once a shot taken the spools end on LP side gets reduced pressure against it and seat pressure becomes less ... What happens is essentially a CREEP, but not the same as above, as pressure from HP side slowly weeps past the seat until set pressure is reached and seat seals once more.

Ideally regulators react swiftly to pressure differential coming on / off there seats near instantaneously when LP side pressures fall a few 100 psi or less.  * Different reg designs / plenum volumes make this a non specific pressure range.

FYI ....
Scott

[nervoustrigger]

Hmm, if it's not creeping then I don't know how to explain the fast first shots.  The combination of elevated pressure and heavy hammer strike sure sounds like the right recipe.  Perhaps it is intermittently creeping but if you cycled it several times and it didn't do it, that's increasingly unlikely.

I could have swore I read a post of yours where you swapped out internals in another brand (JDS I think?) of regulator with a ninja piston, but I can't for the life of me find it.

You are probably thinking about Rob's rebuild of a JDS reg on a Flex:
http://www.gatewaytoairguns.org/GTA/index.php?topic=110281.msg1057552#msg1057552

Notice in his picture, the JDS reg on the left has the seal visibly imprinted with a ring where it meets the valve seat.  Each time the regulator cycles, there is a potential for the mating surfaces to not come together neatly and that aggravates the creeping problem.  The more gnarly that surface becomes, the greater the potential it will behave erratically.  That would be something to visually inspect if and when you disassemble the reg.

[imadunatic]

That is exactly the post I was looking for, had it in my head it was you, probably the reason I couldn't find it.

I'm not sure I'll be able to wait until the bottle gets all the way to zero. It's -1 here right now, so the shooting season is more or less indoors or nothing (I do have a 15m range in my garage, but even that can be frosty when it's below zero outside!). Eventually I'll probably just drain it and disassemble so I can see what is going on. May just order a ninja rebuild kit when I do it if the guts look less than awesome.

Scott/Jason, thanks again for the help and advice. Always learning.

Kevin

[BigTinBoat]

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[imadunatic]

Thanks Rob. For both your initial findings and commenting here.

I'm about to buy three 13ci Ninja bottles, which will render my bench bottle semi-retired for now, I'll probably pull it apart, and if the pics match the innards of the JDS you posted I'll just order the Ninja rebuild kit and replace everything (and bump the pressure slightly, 700 is a little low, even for a bench bottle.)

For the interest of science, I'll post pics when I pull it apart, maybe that will help the future googler to know what's in the Valken Regs and they can decide what to do with it.

Hindsight being 20/20, I should have just ordered a 62ci Ninja, it was the same price as the 48ci Valken.