My Ariston boiler heats water on demand and central heating.
The boiler keeps coming on and heating up the radiators even though I don't want it to. The pressure has gone into 3-4 bar which is too high also.
Is this dangerous and how do I prevent heating coming on?
(There is a small clock face on the controls with thin 'pins' to pull out for when you want the heating on - I pushed all the pins in which I take to mean it should be off all the time. There is also a small switch beside this to choose heating and water, just water, or off - I put it to off). There are two other lights with buttons below, one of these shows a radiator but as this is next to the pilot light I am worried to press it as I don't know what it's for.
Any help appreciated as am v. worried about the pressure/ safety and is also boiling!

Liz, July 2008

hi there having mayor problems with my ariston boiler.the heater nor water is coming on.the flame is going out and making a massive banging noise like a engine back firing.the codes in the window display are 501 then 502 then ao1 in the manual means ingination fault.there is also a smell of gas outside when it is trying to lights.any help would be great.had a engineer out to it but no joy.total brick wall.thanks

tina dyer, January 2009

Hi Liz
just read your problem,If you havent got your boiler sorted e-mail me on ian@iditchburn.plus.com for help.I am an official ariston boiler engineer

Ian Ditchburn, December 2008

sounds like you should have a new boiler aristons arent the best to be honest email me on hallrichard69@yahoo.com for advice im a corgi registered engineer

tricky, July 2008

1st problem is that your expanson vessel is faulty
2nd problem is faulty diverter valve

danny oshea, July 2008