I rebuilt my Huma regulator recently that I used to replace my original M1 FX Impact regulator with. I had developed a leak in the regulator housing (weep hole behind the safety selector switch) so after replacing that O-ring I went ahead and did the rebuild on the regulator. Used all the correct size O-rings that I had in stock. I did not replace the valve disk because I did not have it on hand. Now after setting my regulator at 90 bar (using an FX digital guage) after about 24-48 hours the regulator pressure in the plenum increases to around 98 bar and that results in a HOT first shot. Could the problem be with the valve disk & what part does the disk play in the operation of the regulator.
Huma Regulator Rebuild Problem
- Thread starter beercanshot
- Start date
8 bar of creep sounds normal. Granted i know nothing about FX, but 8 bar after 24 hours isn't bad at all. I have a karma that creeps 24 bar. Many regulated guns creep. They need a few shots or dry fires to reset. The air can leak by the valve sealing surfaces in the regulator if theres a tiny imperfection. The disk has a valve seat around the hole and the valve has to fit it perfectly
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The way the regulator seals is the point of the adjustment screw seals to the plastic disk. So, yes, the disk can cause leakage if the seal is not good with the point of the screw. If you do not have a new one, you should be able to flip it over and use the other side.
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Try flipping the delrin disc over or acquiring a few more. My huma is having a bad day if it creeps 5 bar and 2 is the typical max I see it deviate on a digital gauge (set at 143 bar). A reliable first shot is mandatory for me and dual humas was what I needed for my m3 to stabilize it and not be taking 3 shots to before I try to get a ground squirrel that showed up for 10 seconds.
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Shoot it for a while and see if it gets better or worse. With most good guns, 8 bar creep shouldn’t cause big problems if your tune is good. You are probably already shooting with a 5 bar difference when the gun is full to when you’re ready to refill.
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As an example of the effect of a velocity variation I offer the results of a little shooting I did today. It's windy here but I still shot a little. First was my Bullshark and the first shot was consistent with the short string I shot so no issues. Then the P35-22. It's regulator is up a little higher to shoot heavier pellets which it does very accurately. But I do not have enough hammer spring to find the peak velocity. So it's velocity was about 40 fps low on the first shot. The second was right up there but not the first. As a result it hit less than 1/4 inch low at 30 yards. Given the accuracy I have with this tune I can live with that.
I'm sure 8 bar won't give you 40 fps velocity change so your impact will be even less.
I'm sure 8 bar won't give you 40 fps velocity change so your impact will be even less.
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