Interesting question. I haven't seen anything on this. I bleed my gauges and hoses down.

To avoid trapping air, when I reconnect, I purge air from the hoses to the manifold end by cracking the fitting at the manifold, and resecuring.

I also bleed high side into low side before releasing the low side. Close high side hose end cut-off, blind center tap of manifold or if it's filled w/ refrigerant close the reservoir valve, and open high side valve to vent high side trapped pressure back to low side of system. Close everything and release.

regards

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