On 27 Apr, 16:10, B A R R Y wrote:
Andy Dingley wrote:

In general, no. However a machine that has a slow leak down somewhere
and is going to be switched off for long enough to empty itself is
usually best vented deliberately rather than being left to do it
inevitably itself (or just fix the leak!)

Why is that?

A compressor is a pressure vessel, i.e. it's potentially dangerous if
left pressurised. The risk is small, the convenience and energy saving
of leaving it full outweighs this if we're going to come back to it
later and use that stored pressure.

However if we've got a leak, or we're leaving it for a long time such
that we're _not_ going to benefit from that stored energy, then good
practice is to not leave it lying around. You don't know what it's
going to do, but it ain't going to bake you a cake. There's also the
risk of leaving the compressor powered up (and leaking), which is just
a sizable waste of energy.