Inside the machine is a high-pressure canister that is used to super heat a predefined amount of water. Once the water has come to a boil, and reached a predefined pressure (15bar) and temperature, the light comes on once the pressure switch is made.
If you have recently used the machine the canister will still be hot or if the water level is below the required minimum the time-to-ready will be greatly reduced causing the light to come on. However, if the light comes on and the water has not come to a boil, it could be due to a few reasons.
If the light comes on and temperature / pressure not reached, it could be due to
- a faulty heating element or pressure switch,
- a blocked (due to calcification) water tube, causing the canister to heat up and super heating what ever water is left causing the pressure switch to be made.
These machines are mostly mechanical and requires very little maintenance. The above are the most common problems experienced.
In the case of the pressure switch or heating element, I would suggest checking your warrantee and request a replacement/repair.
In the case of calcification, check the De' Longhi website for a cleaning kit to decalcify the system (Recommended method). If your machine is outside its warrantee period and you do not want to spend the bucks, you could use a home made recipe of white vinegar and water (Not recommended, it could wear down the rubber seals). Just make sure that you rinse the machine thoroughly before making the next cuppa.
Please let us know if you do not succeed and need further assistance.