Spare parts are available for he Ariston electric mini-tank water heaters. These spare parts are user-replaceable.
For the Ariston Gl2.5 and the Ariston GL4 mini-tank water heaters you can replace just the sacrificial GL Anode Rod (#574305) or you can get the Ariston GLKIT for the GL2.5 and Gl4 models. This GL KIT includes the GL Anode Rod (#574305) as well as the GL heating element (#994103) and the GL gasket (#994147).
The GL Anode Rod and the GL KIT will also work for the Ariston GL2.5Ti and GL4Ti mini-tank electric water heaters as well as the now-obsolete Ariston models P10S and P15S.
Similarly, for the Ariston GL6+ mini-tank water heater you can replace just the sacrificial GL6+ Anode Rod (#570241) or you can get the Ariston GL6+KIT for the GL6+ model.
