I finished the job that inspired this question so that others might not have the same trouble, and Jupiter's comment on my answer got me to thinking, "Am I using the can wrong?"

The only fitting that I have that fits my manifold gauge set, has a puncture needle:
enter image description here
So any can that I use it on MUST be emptied entirely, in one go. If only a partial can is used, the rest must be vented/wasted.

Here's what a can looks like after it's been punctured like that and emptied:
enter image description here
As you can see, it has a big, non-resealable hole in the top.

However, I also bought a standalone refill can that came with its own hose, connector, and gauge, and a resealable "button" like a can of spray paint or WD-40. And I discovered after I had emptied all of it into the A/C system, that the hose can unscrew from the can. So here's that fitting:
enter image description here
Instead of a needle-pointed screw, this one has a spring-loaded plunger with a flat bottom.

And here's the empty can that it came off of:
enter image description here
No big open hole here, despite being obviously empty. (much lighter than a full can, and doesn't slosh when shaken)

Now, for this unused can that I would normally have used the puncture fitting on, would it also take the non-puncture fitting, go back on the shelf about 1/2 full, and discharge the rest some months later?:
enter image description here

All 3 of the cans shown here are SuperTech branded (Walmart's store brand), but I'm also looking for a way to tell generically. The can in question is sold as just the can, no hose or anything else, and my manifold gauge set only came with the puncture fitting. In other words, if I keep buying these cheap cans, is it worth finding a non-puncture fitting to use with my gauge set?

The can by itself that requires a separate fitting, has a label that says, "PLEASE CONSERVE" and "Always store partially filled cans with recharge hose attached." To me, that wording doesn't necessarily mean that it can use a non-puncture fitting, because a non-leaking puncture one can also satisfy those requirements...except that my puncture fitting does leak just slightly. Not enough to be a concern in use, but enough to make storage impossible.

1 Answer 1


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The can top picture is a non-puncture can. The tap with a sharp point is the tap for puncture cans. The tap with a flat point is for non-puncture cans. They are very inexpensive.

  • Much better pictures of the fittings than mine! Thank you! But the picture of the can isn't so much. In my pictures, you can see a slightly raised red button just past the top of the can. Yours is hard to tell one way or the other. Is that button in the can itself a reliable indication of being self-resealing/non-puncture? Or is there something else to look for?
    – AaronD
    Commented Apr 15, 2021 at 21:01
  • On the non puncture can, I'd say about 1\8" below the top of the hole is the spring loaded tab that the tap presses down.
    – Jupiter
    Commented Apr 15, 2021 at 21:44
  • Yes, but how to tell that that's really what it is? Is the recessed red nub enough? Is that a reliable indication, compared to the foil-looking flat cover that I vaguely remember? Different design might mean different function, but not necessarily. It'd be nice if there was a conspicuous label to that effect, instead of relying on inference from things like "please conserve".
    – AaronD
    Commented Apr 16, 2021 at 15:05

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