Checking the level of water:

In the case of a manually filled machine, the water in the boiler should be kept at a level corresponding to about the 70% level in the sight glass. When the level drops, a filler tap (operated by a lever or a button) should be used to refill the boiler. In the case of auto-fill machines (also descibed as "self levelling", and composing the vast majority of units sold today) a probe reads the water level, ensuring that the correct water level is maintained.

Nevertheless, it is always a good idea to check the water level in the boiler, even on auto-fill machines. This could prevent or minimize damages caused by electrical malfunctions, probes losing sensitivity, etc.

Checking temperature and pressure:

To ensure the proper temperature of water dispensed by the dispensing unit (approx. 194 - 203 degrees F or 90 - 95 degrees C), the temperature in the boiler must be maintained at a higher level. This is because 25% of the heat is dispersed when the water passes from the heat exchanger (located inside the boiler) to the dispensing unit. In other words, the temperature drops from 248 to 203 Degrees F (120 to 95 Degrees C).

This dispersed heat keeps the metal components at constant temperature, and ensures their proper functioning. If these components are allowed to get too cold, the quality of the brewed coffee will suffer. This means that the boiler must be kept at a constant temperature of around 248 Degrees F and that the pressure gauge should read approximately 14.7 psi. (1 atm.). If the pressure gauge indicates a higher or lower pressure, it should be adjusted by turning the regulator screw on the pressure controller. Loosen it to reduce pressure, tighten it to increase pressure.