Ar 4gpm pump help

So I bought a used 11 horse honda motor and bought a new direct drive ar pump 4gpm 4000 psi with unloader. Everything works great but the only issue I have is when I let off the trigger and machine goes into bypass ( which I have ran to a tank ) when I get back on the trigger it doesn’t come on smooth it blasts hard then smooths out. Not really sure why that is. Same if I shut the machine off while it’s in bypass rather than bleeding off pressure into the tank it stays trapped in the line until I squeeze the trigger. Any ideas?

The unloader is designed to bleed off excess pressure when you get off gun.

http://www.arnorthamerica.com/pages/the-role-of-the-unloader/

I may have the same pump (RRA4G40), and I’ve definitely experienced the same affect. I never considered it a large issue, but the initial high pressure could cause damage on delicate surfaces and the kick could become irritating. I imagine the unloader could be set a bit too high on pressure (i.e. 4300 psi vs 4000 psi)? This is my first machine and I figured the kick was normal.

You’re generally going to get that with a pressure trap unloader tho some are better about it than others. Reason a lot of people go to a flow actuated unloader so you don’t get that kick when you start. Just be sure not to be aiming at anything sensitive when you first pull trigger with any unloader. PW101

I bought a new 8gpm machine with a General pump 2 months ago. It would do that consistently for about the first 10hrs of use…since then it has almost stopped doing it…just does it occasionally, now. It is almost as if the unloader had to break-in…IDK

Good to know. I planned to switch to flow actuated when I get my buffer tank setup. This gives me another good reason to.

Once you use one, hard to go back to the other. I still have on my 4gpm machine and I almost cringe anytime I use it, lol.

Well good to know that’s all it is, I can’t stand it though haha so I think I’ll be switching to a flow actuated unloader. Thanks for the insight

But I’m old and puny, you young whipper snappers shouldn’t have any problem.

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