Ariston [103] fault codewhat it means and how to fix it

Ariston use a block of codes, 103 through 107, for insufficient circulation, along with the 1P1 to 1P3 warnings for the milder version of the same condition. The appliance works out flow indirectly by watching how quickly the temperature difference between flow and return develops when the burner fires. Water moving properly carries heat away and the two readings stay close together; water barely moving produces a rapid, wide split. When that split exceeds what Ariston consider safe, the appliance reports this group of codes and reduces or stops firing. The valuable thing about seeing 103 rather than 101 is that you have caught the problem at the stage where it is still a circulation fault rather than an overheat. The same causes underlie both, but at this point the heat exchanger has not been repeatedly cooked. Acting now is materially cheaper than acting after two more weeks of resets.

1. 1

   Check the pressure is 1.0 to 1.5 bar cold and top up through the filling loop if not, using the Mode-button purge cycle as Ariston specify.

2. 2

   Open all thermostatic radiator valves fully so the system has somewhere to circulate, and check any service valves below the appliance are open.

3. 3

   Bleed the radiators, working from the ground floor upwards and finishing with the highest one in the property. Top the pressure back up afterwards.

4. 4

   Run the heating for half an hour and note which radiators are cold and whereabouts on the panel. That pattern is the most useful thing you can hand an engineer.

5. 5

   If the code persists after bleeding and repressurising, book an engineer while it is still a circulation fault and not yet an overheat.