Remeha Avanta Plus 35c E4 Error

28 May 2009
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United Kingdom
Hi, I have a Remeha Avanta Plus 35c combi boiler and I'm having the fitter round saturday to look at it as it keeps cutting out with E4 errors.

I just wondered if anyone has had experience of this?

I have a flame that looks quite stable but after 2 seconds it cuts does this 5 times then gives the E4 error.

I'm suspecting its something with the ionisation current is supposed to be between 3uA and 9uA but when I monitor it when the flame forms FL on the display only goes up to 0.2uA so I suspect the sensor for the current may be faulty or needs major adjustment as the flame looks ok.

I want to make sure if parts are needed he has them for saturday so he can get it working.

I am happy to a have a go myself at adjustments if I can get it going but am staying away from the gas as I know I need to be corgi registered to touch any gas parts.

Cheers, Rob
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Hi, I have a Remeha Avanta Plus 35c combi boiler and I'm having the fitter round saturday to look at it as it keeps cutting out with E4 errors.
The Installation Manual Page 53 tells you what to check if you get this error.
The CO2 adjustment will need a GSR man with the necessary equipment. ;)
have a look at page 47 i think.

remove front cover, remove HT lead and remove electrode and give it a clean with some emery paper, replace electrode, replace HT lead and test.

measure the flame signal now and see if its in range
Cheers for the suggestions chaps.

I did take the electrode out and clean it up as it was quite dusty, but it didn't help, I also cleaned the unit out as it recommends in the manual with a hoover.

I thought the adjustment may be off but I can't understand how it can of changed that much for the ionisation to now read 0.2uA instead if 6.
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Because its a safety device you should not be removing the electrode if you are not Gas Safe registered ( was CORGI ).

Measuring such a low ( half wave ) current in the presence of a voltage is not always done in a way which gives the correct answer. EDIT I suppose you have done that from within the boiler menu. Being too low can be a PCB fault or another fault so that leaves as many questions as it answers!

There is always a possibility that the PCB has failed if everything else seems OK. This fault is usually caused because a high value resistor ( usually 1 Meg ) in series with the electrode has gone open circuit. To test it it needs to be measured with the electrode connection removed.

The detection lead can be measured for continuity from the electrode tip to the PCB connector.

Sometimes there is a build up of conducting dust around the PCB tracks or the electrode insulator.

First thing that your engineer will need to do is check correct working pressure at gas valve, then check combustion high and low. If all is Ok replace rope gasket around burner if this fails change ignition transformer almost always the problem. Most of these boilers are still under warranty and their engineers carry all these spares.
Thanks guys, I think I will try giving the tracks a clean tonight with some pure alcohol and see if that does the trick if not its wait until saturday.

Does anyone know where the boiler internally monitors this ionisation current from?
The MI are not very good but most similar boilers have an ignition HT unit with four connections, two for the supply close together and two spaced apart with one being the HT connection to the electrode.

The spaced connector, which is not the one to the electrode, can be called the HT earth return and is connected to the PCB where it has a resistance to earth to allow the ignition current to flow. In addition a voltage is applied of about 100v AC and a detection circuit looks for a DC current flowing. It does this by looking for an offset DC voltage to earth after the AC has been filtered out.

Due to the high impedances involved, unless you have a working one to compare it with its almost impossible to do much apart from measuring the various resistances involved.

On the HT unit used in Biasi boilers the resistance across the output side is 1336 ohms.

The HT unit used in the Viessmann has an earth connection to the chassis as well.

ok,these are good boilers.
but they really need an experienced gas engineer to repair.
probaly the smaller acrylic rope gasket that sits inside burner flange but outer larger gasket will also need exchange.
had mine serviced last month and engineer first connected his pda to boiler,went to his van and changed several gaskets including both above.
he set up combustion readings,and all is ok.
before some lockouts e4.
ok this is in my flat in amsterdam.
ps call in an expert.
good luck.
From what has been described, I can see no reason to open the combustion chamber.

The boiler may well still be under the warrantee but that may have been invalidated as a result of the boiler not being serviced annually.

It only sounds like a typical boiler fault and nothing unusual.


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