My Ariston Microgenus HE32 has been installed in December 2005. For the last 2 - 3 months erroe E34 or E33 comes and goes from its electronic display. I looked up the Boiler's manual and it indicates that Air Pressure Switch is gone. Today I replaced the switch with the new one, but the error still appears. I suspect that the flexible silicone tubing that is connected to the switch might be blocked. On Saturday I am planning to take a closer look at the tubing and clean it thoroughly.

Tad Warchol, me address is tad.warchol@directline.com, March 2008

Disconnect the two spade terminals on the air pressure sensor.
Connect an ohmeter. The resistance should show infinite before the fan starts and approx zero ohms when the fan is operating. The logic board checks both these conditions.
If this is not the case, turn power off and locate air tube the runs from fan casing to sensor. Disconnect at fan casing end. Check switch activates by blowing down tube - you will hear a slight click and the resistance should drop to zero. The sensitivity is high (.55mbar) and it should close switch even by blowing towards the tube.
It seems the fan impeller is of poor design and sometimes not capable of producing .55mbar pressure in the chamber.

steve watt, August 2012

ive had error e33/e34 coming up fa some time.just replaced air pressure switch & still the error came up.have removed fan & given it really good clean of dust.boiler now firing up every time and so far no error 33/34.fingers crossed now CURED.good luck guys

smudge, May 2011

help; did you get your E34/E33 sorted.

wendy, August 2009

Answers - mend, repair, fix
If you are getting this error or the E33 error take note, complain
I'm having an E34 error, I had it before two years ago, they came and replaced the PCB. It's nothing to do with the pressure sensor or flue, or restrictor, it's shoddy design. apparently they had to do it with most of the microgenus HFFI XX HE boilers from what I can tell. I'm also getting E33 errors too, it practically unusable, we have to boil water up with a kettle.
I'm going to phone them up tomorrow and complain. I'm demanding nothing short of a full replacement at their expense, this set of boilers are obviously not fit for purpose. Everyone should pursue method, get BBC Watchdog involved, they know these are faulty. What happens when people get to the end of the 5 year warranty, they simply buy a new one?
These things should be lasting 15 years minimum. Frankly I'm appalled and will never buy Ariston again, I curse the gas plumber who recommended and fitted the thing.

Christian, July 2009

Did you ever manage to fix this problem. I am having the same problem with my boiler

cliftonsmith@vodafone.net, November 2008

The fault may not be the restrictor ring. If the boiler has been installed and set up correctly, the restrictor ring will be there for a reason. This fault can be caused by a build up of dust or dirt on the fan blades; a faulty fan; a faulty switch,a blocked or faulty flue, a restriction in the air pipes that feed the switch etc. You should really get a CORGI registered fitter to service the boiler paying particular attention to the fan; the pressure switch and the flue.

Pete, October 2008

yes that sounds simple but how do i actually remove the elbow to get inside?

scott, July 2008

there is a restritor ring under the flue elbow remove it and thi will solve E34 ,this is a manufacturing fualt.

voggas, May 2008