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This is very difficult to diagnose remotely, but it sounds like what happened to you is that it self-vented through the high pressure relief valve. On older cars, it would sound like a shotgun blast and vent all at once.

Do you know how much freon was used to refill it? The factory fill amount is on a sticker underhood, and is typically anywhere from 20 to 30 oz or so (about 2 to 2 1/2 cans). If it wasn't overfilled, then probably there is a clog or similar malfunction that caused pressure to build. If so, you would need to find the source. There is a drier canister filled with dessicant inside a plastic baggie in a metal can, and if it leaks, it will clog the system. Or, if these systems still use a needle valve as the expansion valve, that can stick and cause pressure to build.

If you can get a set of gauges, you can verify if this is happening. Pressure on a very hot day should not exceed 300-350 psi, and it may release around 400 psi. For cooler ambient temperatures such as 80F or so, high pressure should be around 250 and low maybe around 30. These are rough guides. If there is a wider difference, and low pressure is 10 or less (or even suction), there is a definite malfunction.
 
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