Pneumatics issues

We’ve just got the basic pneumatics kit 1. It’s all hooked up and working but only really works while the pump is connected to the gas cylinder. When it’s connected, we can pump up to about 100psi and the piston pushes really well; when we remove it, there’s a quick hiss between disabling the pump and pulling it off. Then, the piston performs quite badly and runs out quickly.

Is this a problem with the pump, or a problem with the setup?

I’m not gonna lie, I’ve never used pneumatics. But from what I’ve heard, the source of most problems is tubing that isn’t airtight. I’d check and make sure everything is fitted right.

Yeah, definitely should double check that. The thing is, when the pump is connected, there’s no air leakage, so I’d not be sure what would be going on there.

Do you have any sharp parts that the tubing might be exposed to? Maybe there’s a puncture somewhere (although I’d sure hope there isn’t!).

ya. my team had a similar issue. turned out that the tubing wasn’t fully connected to the pump. one way to tell is if you have a valve between the tank and the piston, then you can isolate the issue.

Based on your description, you’re losing your pressure when you disconnect your compressor. Take a look at this thread: Better way to fill up pneumatic reservoirs

The problem is the release between the air reservoir and pump. Schrader values aren’t easy to remove without loosing air. I would recommend picking up a quick release valve (this was my teams solution, which still looses some pressure but not much) or finding out how much air is lost when removing the pump. Then add that onto your 100 psi. So if 20 psi is lost then pump it up to 120 psi and you should then loose 20.

But also check your tubing and seals just to be sure.

Good luck!

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Don’t think so luckily

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Okay, might try that

Thanks, that might be a solution, though I’m not sure we have enough parts for that

Just a heads up under rule R25 this is illigal

R25 Pneumatics are limited: Pneumatic devices may only be charged to a maximum of 100 psi. Teams may only use a maximum of two (2) legal VEX pneumatic air reservoirs on a [Robot]

You are only allowed to fill up to 100 psi regardless of how much pressure you lose.


It doesn’t state that you can’t do this. As long as your pressure when you start the match is less than or equal to 100 psi. The reservoirs can handle much more pressure so there isn’t a safety risk.

Also just to clarify I was talking about how much pressure you loose when disconnecting your pump from your reservoir.

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I agree that reservoirs can hold more pressure(they are rated to 250 psi) but R25 says in the 2021-2022 Game Manuel you can only charge to 100 psi. If you try to pressurize to a higher pressure to compensate for the pressure you lose, you run the risk of getting a warning and eventually disqualified. At almost every tournament I have gone to, they have made sure to enforce this rule, including signature events.


Generally speaking, robot rule apply during matches. If you briefly over-fill the air tanks in the process of getting ready for the match, as long as the air tanks are under the limit before the match starts you haven’t violated a rule.

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Have they checked your air pressure?

This is true; however, this specific case applies before the match, given that one may not charge a reservoir during a match. The limit specifies what one may “charge to”, not what one may “start with”.

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The other problem is that because there is no legal pressure gauge, you can’t know for sure that the pressure you lost when disconnecting the fitting dropped the system to 100psi or below.


Would it be unreasonable to say teams with one reservoir could be allowed to overpump with the current pneumatic shortages? Instead of having to worry if they hit 120psi before the match or not?
I don’t know, the allowance of pneumatics without penalty has made things a touch difficult this season and I’m sure this won’t be the only one.

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Yes, when running skills they have checked that I filled up to 100 psi

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Sounds like you have a leak. Check that all tubing is pushed in and the threads are taped and not leaking

Use thread tape, it works