it is worth pointing out that the significantly shorter distance from the boiler to shower screen on the Cremina group means that once the first espresso has been drawn from the machine it stays very close to operating temperature whilst left at idle.  It will be slightly on the cool side, but the clever design of the group allows you to circulate water through the group and back to the boiler without dispensing any water through the shower screen.  To do this raise the lever arm to just above a horizontal position (if you go too high water will obviously gush from the shower screen), and then simply return it to the resting position.  One of these partial upwards and down movements will be sufficient to bring the group up to operating temperature.