hi code E 34 comes up on my ariston micro genus H.E. boiler
it says in booklet -air pressure switch does not close when fan runs.! this is happened a few times and its says it should reset it self but it does'nt

steve shoults, March 2008

Further to my previous answer,

the replacement air pressure switch is of a different design to the original, some modification is required to make it fit the mounting plate.

the rounded part in the front of the mounting plate will need to be cut away to allow the new airflow switch to sit flush, you will also need two M3 x 20mm bolts and nuts. (the fixing screws for the previous airflow switch won't fit the new one).

Doug

Doug, March 2008

there is a known fault with the air pressure switches on this model, don't order the replacement listed in your installation and servicing instructions, order part code 998484 instead.

(mine just failed too, the boiler engineer i called spoke to Ariston parts center)

Doug, March 2008

switch off boiler ,remove casing & detatch rubber hose off pressure switch & blow through rubber tube to mnake sure that it is clear. it also may have a little airflow restrictor inside it also make sure that is clear from any blockages. attach casing back ,switch on & try again.

gary, March 2008