Everything that I've read so far says that pouring cold water into a warm boiler is a no-no.

As I pull more shots, I become impatient with the wait for boiler cool-down, and then it strikes me. I can use my electric kettle to bring cold, fresh water up to a boil then pour it into the boiler! I can't think of any negatives, but maybe I'm missing something. Are there any reasons NOT to do this?

-s.

Waiting for the boiler to cool avoids exposing the heating element to a sudden temperature change that could crack its ceramic coating. Preheating the water as you suggest should certainly eliminate the need to wait. Seems obvious now that you point it out!

WARNING: As a reminder to those reading this thread, always release boiler pressure via the steam wand before removing the cap! Verify the pressure gauge reads zero too. Or be patient, turn the machine off, and wait until it's no longer hot.

Thanks for revising the topic headline. In retrospect, you're absolutely right - this applies to any direct fill machine, not just the Cremina. What I've been doing is turning off the power, putting a pint glass or 20 oz. pitcher under the steam wand and letting it literally run out of steam, closing the steam wand then refilling the boiler with just-off-boil water from the kettle.

Seeing as how the Cremina's boiler is relatively small, my electric kettle heats up 20 oz. of water in almost no time. Once filled, it comes up to operating pressure very quickly.

Safety first! (or second, after espresso!)

-s.

Yes, if I need to refill fast I just turn off the machine and let all the pressure off at the steam valve. I had not thought of preheating the water, but is a good idea to avoid shocking the element as you suggest.

It does only take a few minutes to be up to temp again, since all the metal is already hot,
PC

You could put that steam to good use by heating up the refill water with the steam wand, sort of like regenerative braking on a hybrid.

Can't try this myself on my open boiler with no permanent steam wand, I just lift the hat and pour in more water if needed.