Ariston [101] fault codewhat it means and how to fix it

The leading 1 places this in the central heating group, and 101 is the overheat trip. It is tempting to read an overheat as the burner running too hard, but that is almost never what has happened. In practice the burner is producing heat at its normal rate while circulation has failed, so nothing carries that heat away and the temperature climbs until the safety cut-out operates.

Everything worth investigating is therefore on the water side. Ariston group the related faults helpfully: their table gives 103, 104, 105, 106 and 107 a single shared description, insufficient circulation, and any of them can appear in the days before a 101. If your appliance has been showing one of those and has now overheated, that was the early stage of the same problem.

Do not read the 1P warnings the same way — 1P2 is a failed flow check, but 1P1 is about the boiler's parameter settings and 1P4 is the request to top up the pressure, so they are not all circulation. The reason not to simply keep resetting is that the heat exchanger is the most expensive part of the appliance, and firing it repeatedly without flow is how it gets destroyed.

1. 1

   Switch the appliance off and give it half an hour to cool. An overheat trip will not clear while everything is still hot, and you will otherwise think it is dead.

2. 2

   Check the pressure reads 1.0 to 1.5 bar cold. Low pressure and poor circulation are frequent companions.

3. 3

   Open every thermostatic radiator valve fully and confirm the service valves under the appliance are in line with the pipework.

4. 4

   Run the heating twenty minutes and feel each radiator at the top and the bottom. Cold at the top means air you can bleed; cold at the bottom means sludge you cannot.

5. 5

   Reset once. If 101 returns, stop and book an engineer.

   Repeated resets fire the burner into an exchanger that is not being cooled. This is exactly how a pump replacement becomes a heat exchanger replacement.