Ariston [501] fault codewhat it means and how to fix it

The 5 at the front tells you this is the ignition and detection group, and 501 is the lockout that follows repeated failed attempts to establish a flame. Ariston distinguish this from the warnings that precede it: 5P1 and 5P2 record a first and second failed ignition attempt while the appliance is still trying, and 5P6 is a general ignition-failed warning. By the time you see 501 the appliance has given up. Ariston describe this as a non-volatile shutdown, meaning it will not clear itself and needs a manual reset. What the code cannot tell you is why the flame never appeared. Four causes account for almost all of them, and helpfully the two most common are things you can investigate yourself: no gas actually reaching the appliance, and a condensate drain frozen solid outside. The other two, a worn ignition electrode and a gas valve fault, need an engineer.

1. 1

   Light a gas hob ring. If it will not light either, the gas supply is the problem and the boiler is doing exactly what it should.

2. 2

   If you are on a prepayment meter, check the credit including any emergency credit that may have run out overnight.

3. 3

   Outside, trace the white or grey plastic condensate pipe down from the appliance and feel along it for a solid, ice-cold length — the bends and the open end freeze first.

4. 4

   Thaw any ice with hand-hot water poured slowly along the pipe. Boil a kettle and let it stand ten minutes so it is hot but not scalding.

   Never use boiling water, a heat gun, or any naked flame. Cracking a cold plastic pipe turns a free repair into a plumbing job in the worst possible weather.
5. 5

   Press reset once. If the appliance lights and holds, the condensate was the cause — get the external run lagged before next winter.