Ariston boilers use a flow of natural gas to heat water. If your Ariston keeps turning off unexpectedly, you may notice water suddenly going cold, or -- if you stand by the boiler when it is working -- hear the burners click off when they should still be working. This is a sign of a malfunction with the system. Several different components, depending on the age and type of Ariston, could be responsible for the problem.
Settings and Pressure
Check all your boiler settings. If you have set the temperature range too high by accident, the boiler may be overheating, creating too much pressure, then shutting off as an emergency measure every time it tries to work. Your Ariston manual should indicate the proper temperature range for your system. Access to the controls are located inside the boiler on the primary control panel. If you begin here, you may save a lot of unnecessary work later on.
If your settings are correct, your thermostat may not be. The thermostat in the boiler depends on heat sensors, usually basic thermistors, that are located at the top and bottom of the boiler. If these sensors malfunction or become loose, they will send the wrong signals to the main controls and potentially cause the boiler to suddenly switch off. You can examine these sensors for proper attachment and test them with an ohmmeter if necessary.
Ariston boilers depend on proper gas flow to keep working. Sometimes the pilot light will malfunction and suddenly shut off, preventing the boiler from heating. Clogs in the fuel lines, fuel valve malfunctions and buildup around the burner can all cause issues that may result in the boiler switching off unexpectedly. Clean your burner, replacing any malfunctioning valves, and position your ignition system correctly to avoid these problems in the future.
Scale is the result of hard water being heated in your Ariston. The minerals in the water precipitate, gathering on the bottom and sides of the water tank as well as inside the pipes leading out from the boiler. Over time the scale can cause loud boiler noises, inhibit warming and create serious pressure problems that may prevent the boiler from working. A water softener may solve these problems in the future, but replacing the scaled parts of the boiler is the best immediate solution.