microgenus A77 error code

[peteuk]

I have a Microgenus HE 32 MFFI boiler which keeps cutting out with error code A77.
The manual says this is due to either:
- Condensate trap full of water
- Condensate sensor short circuited
- Condensate sensor in open circuit
When we first had the bolier installed Ariston changed the recuperator when this fault kept occurring.
Recently the problem has started again. Unfortunately the boiler is now out of guarantee and our plumber cannot find the problem. Ariston are advising it may be an installation problem saying the boiler may not have been installed level) but our new plumber says it seems ok.
[There was a history of problems with the boiler's installation by a previous plumber but we had thought these had been resolved]
Does anyone have any advice - I'm almost inclined to replace it even though it's less than 3 years old!!

 

[Rob]

Has the condensate trap been checked? Has it ever been cleaned out since it was new. Seen some pretty bad ones even after a few months.

 

[peteuk]

Thanks Rob884.
The trap was checked recently - last time the plumber came out.
He's coming again tomorrow so I'll mention it again - he's also going to recheck the that the route from the trap is clear to the waste.

 

[peteuk]

The plumber came and looked at my boiler again and said he can find absolutely nothing wrong - and all is clean.
It's worked ok since then.
In case it happens again, does anyone have any other ideas?
(My wife wants me to take out a BGas Homecare plan which I am loathe to do for a 2.5 year old boiler)
Thoughts:
Could it be something to do with the outside temperature - it happens more when the temperature drops. If so would setting it to "comfort mode" help?
Coud the sensor itself be at fault?

Thanks again.

 

[Agile]

The answer is that it could be anything but was only one thing which we dont know!

Does the condensate trap have a ball which could have become stuck ???

It always surprises me that people jump in and start dismantling things without just starting by disconnecting the condensate trap electrode first.

Tony

 

[peteuk]

Thanks for the reply Agile.
Sorry my response has taken a while. Work and other things have kept me off the net.
Last night the system went off with the same fault again (A 77) and then allowed me to reset it after a little while.....we're now getting into ultimaums about new systems.
Again it was a colder night - could that be a factor? To answer your question:
I'm pretty sure there isn't a ball in the condensate trap. The waste comes into the trap through a pipe from the top to the bottom, fills up the outside cylinder of the trap and then flows out through another pipe at the top (sorry for my poor explanation).
Not sure what you mean by disconnecting the electrode. Are you meaning to test if that's the problem?
My plumber says he's done all he can now but if you can clarify what you mean or if anyone could give me any other advice I'd be grateful.
Thank you

 

[fat paul]

hello
i've had the same snags with mine, and its an easy fix. you'll need to take the front cover off and then the sealed chamber front cover ***** might void any warranty you have***** and i think it might be a corgi job but it's up to you i'm not corgi - i'm a royal navy nuclear engineer - but you aren't messing with any gas lines so you should be ok.
if you look in the top right you can see the latent heat exchanger unit, there are 2 sensors coming off this, the one behind the air pressure switch is the fume sensor, and the other is at the bottom of the heat exchanger next to the fan. I must hazard this next bit is an educated guess but this sensor is the condensate trap sensor, i'm assuming that if the trap is blocked the line backs up into the heat exchanger??? again only an educated guess. I found that the contacts on mine were in poor condition, they do sit below the fume outlet which is potentially open to the elements. anyway a good clean up and the boiler ran first shout.

hope this helps - just make sure you turn it off at the wall before you open it up

 

[plumberfix]

Hi heres how to fix this simple problem..

error A 77 tells you there is water in the system that isnt wanted.
in this sinario all you do is disconnect the condensate pipe from the waste trap under the sink or where ever it is conected to and make sure its completely empty of water. instead of puting it back on the sink trap just leave it in a bucket, make sure it is in a constent flow downwards. you see if the condensate waste pipe gets blocked with water your ariston boiler will think its got a sort curcuit or it will say condensate trap full off water..
i had this problem and this sovled it.. please not if you fix boilers or anything to do with gas you sould be corgi registered...
as this repair does not invovle gas you should be ok.. but please consult a qualified engineer before attempting any repair on your own.. hope this helps guys...

 

[Gasguru]

If the boiler is installed as per the manufacturers instructions a blocked condensate pipe to the drainage WILL NEVER cause an A77 error.

There must be an air break between the flexible condensate pipe from the boiler to the condensate pipe to the drainage syatem.

 

[zk]

The microgenus has two types of recuperator, the earlier types condensate sensor came with a white lead, and the later with a purple lead. As the recuperator in inside the combustion chamber, you would need an RGI to check. I would also check the water sensor circuit board, which is mounted under the cover which you have to remove to access the main pcb. The reason why Ariston say the boiler may not have been fitted level, is because the condensate sensor is fitted to the lower left side of the recuperator, if the condensate does not leave the recuperator quick enough, then it effects the resistance of the sensor and hence the a77 error.

 

[plumberfix]

well i fitted my boiler myself wasnt exactly rocket science and i save myself £700.

corgi registered rip off hhahaha well as i said i had this a77 problen and clearing the blockage of water in the waste done the trick my boilers working great now. cant see how a boiler mounted unlevel will cause a problem unless its well unlevel.

mine isnt spot on and works fine.
beware of corgi rip off's make sure you get someone you can trust.

 

[zk]

Plumberfix, just because you fitted your own boiler, your now an expert on diagnosing boiler faults. If you had fitted the condensate discharge pipe with an air break as required, you wouldnt have had your a77 error problem." Corgi rip offs "as you call them, RGI's are held accountable for installations that are not to standards. I attend numerous in warranty call outs, where the installations are done by homeowners and non registered gas installers, the appliances are disconnected and notices left due to dangerous installation errors. With regards to the boiler being fitted level, if you read and understood my reply, it clearly answers your question.

 

[plumberfix]

zk i never came on here looking for a argument. i posted my expierience as i had th eproblem and i hoped it helps others. and yer corgi are a rip off mate. they charge way over the odds and they even charge a call out fee.. you should watch watch dog sometime and see the so called corgi guys in action charging old ladys £300 for a 5 min job..
anyway not going to argue with you..

alavista

 

[Gasguru]

plumberfix you're no plumber or heating installer just a numpty arrogant diyer

You failed to install the boiler as per the manufacturers instructions and that constitutes a safety issue and resulted in boiler faillure.

Since your waste pipe blocked it suggests that is also poorly installed...virtually all blockages I attend are from botched installation.

Your then get all arsey when some of us criticise your anti corgi stance despite being a cowboy yourself. The good corgis that spend time on this forum giving free advice get a little ****ed with pretend plumbers like you.

 

[assured heating]

Now Now ! ladies calm down plumberfix cant help if the 2week training course did'nt get him his gas qualifications (that might be a good thing) the reason corgi engineers charge more than TURD TECNICIANS (plumber) is we have more overheads because we are more technically biased ie more tools ,exams ,insurance etc so there!!!