Espresso machine has to warm up halfway through pulling a shot I've had my espresso machine for a little less than a year. It's a DeLonghi EC155. It heats up fine (I assume so - a green light that means "ready" turns on, and I've followed the instructions and let it sit for 30 minutes heating before using it), but when I pull a shot, it makes the sound of the water being pushed through the grounds, but the green light turns off halfway through the process. I stop pulling the shot, wait for the light to come on, and finish pulling the shot.

Usually when I dispose of the grounds, they're very watery. Is there a way to make the machine hold heat longer, or is it a defect with the machine?

EDIT: It should also be noted that the light turning off halfway through is a relatively new occurrence. Before about a month ago the "ready" light would stay on until after I had pulled my shot.
Why do you stop in the middle ? Is there a drop in pressure ? does the coffee continue dripping down in the cup?

Let it finish.

I assume, if it is working like my machine, that the water is being re-heated for a next shot.

1st thing I would do is to clean the machine with a "descaler"; it should help with the water heating system and the pressure.

If that does not help, have the machine looked at.