Ferroli Modena 102 - Fault find for me please chaps!!

Dannypipe · Jan 3, 2011

Hi all, I've been out to repair a Ferroli Modena 102.

The hotwater is running hot, then the burner shuts off and the water turns cold. Then it sparks up again and turns warm again.

Also the heating cycles (it turns on, burns and then cuts out, then within seconds sparks up again and runs, so on).

This could be because the boiler is far too big for the little house its in. 6 rads in total.

I have fitted a part suggested to me by the fault flow chart, which I didnt agree with 100% so I called Ferroli and they agreed with the chart. (Water Pressure switch) - It didn't work, but then I forsaw this.

I need to get it done on my second visit as I'm so pushed for time, plus my other half now fully 9 months pregnant, so any day I'll have to drop everything and help her out!

Figured Gas Man would have experienced something along these lines. I have my suspicions that either a thermistor needs changing or the DHW sensor needs changing.

Oh and the client said that since I changed the Water Pressure switch, the ignition is much quieter....I said it shouldn't be. My thoughts are that when i drained the boiler to fit the part, I may have removed some S*** from it as the water was as black as coal.

Thanks in advance for any responses. Sorry to have banged on!

Danny

cjg · Jan 3, 2011

flame detec fault?

Dannypipe · Jan 3, 2011

Possibly, I would doubt it would run as well as it does though. The house is piping hot, there's no complaints from the client about the central heating side. Though as I said, I noticed it clicks on and off reguarly. I've not run the boiler from a cold system which would be interesting to do as I would then be able to tell if it was the flame detec, as it would still cycle like it does on warm up.

If it heated consistently from a cold system until it reached temp, then i would be able to eliminate flame rec.

I have suspicions that the reason it cycles on heating is that the boiler is so oversized but that could be a red herring.

Thanks for reply.

Blake · Jan 3, 2011

There are several things that could cause this mate, thermistors, poor circulations, APS etc etc.

Have you checked the thermistors for correct resistance?

Billy Bob Bob · Jan 3, 2011

right danny pipe first suspect is the thermistors,but have you removed the combustion door and tried it?if it runs normal its a good chance the plastic venturies have collapsed but be warned as soon as you remove the hoses they will break anyway,if not venturies then aps also check gas pressures

Blake · Jan 3, 2011

Also has the boiler always cycled on heating, if it was an issue with being oversized I would have expected it to have always done it.

hihowudoin · Jan 3, 2011

maybe DHW waterways in Heat exchanger scaled up causing OH ?

Billy Bob Bob · Jan 3, 2011

my moneys on the venturies or thermistor

stevetheplumber · Jan 3, 2011

i see very few scaled heat exchangers its usualy dirt in the heating ways of the heat exchanger id make this the first thing i looked at drop the plate heat exchanger and see how much black crap is in it
its usually two screws to get this of
as boiler runs fine on heating it has to be something that only functions on hw

Billy Bob Bob · Jan 3, 2011

it does not have a plate heat steve

hihowudoin · Jan 3, 2011

beat me to it gasman lol, dual flow heat exchanger on this model

Billy Bob Bob · Jan 3, 2011

yes its a twinpass,most ferrolis are except that new band a shed

Dannypipe · Jan 3, 2011

Cheers guys, brilliant advise as per.

I don't know if it has always cycled during central heating only as client was unaware, though they did say the hotwater was consistent.

I haven't checked the thermistors for correct resistance as I can't get the figures i need, the tech Ferroli guy was even vague!

I haven't removed the combustion door as yet, thought I'd post a thread on here first so i can check the right things on the first pass and save time on site.

I suspected a thermistor, but didn't really think about the venturies.

Good advise lads, I will open the door tommorow and check the venturies, the impulse hoses...don't think I have the figures to check the aps.

I will photograph whatever the culrpit was and post back here tommorow evening. Thanks everyone.

Billy Bob Bob · Jan 3, 2011

be carefull with the hoses danny,i would advise you pick up a set of venturies at £6-9 they are not dear,you are in trouble if they fall apart,unless your skilled with the old super glue LOL good luck mate let us know how you get on with thermistors you get roughly 11k when cold,resistance reduces with temp

Dannypipe · Jan 3, 2011

Cheers for the heads up. I will report back with lovely piccies tomorrow evening!

I'll swing in to PTS in the morning and pick up some venturies, I'm not handy with the super glue, tend to stick my hands together most of the time!

Billy Bob Bob · Jan 3, 2011

LOL fan comes out easy to replace them if needed

mikegas · Jan 3, 2011

its prop basic but why does the boiler fire with the cover off if the venturi has fried?

Billy Bob Bob · Jan 3, 2011

what tends to happen is the venturie snaps and moves in a sealed combustion chamber the boiler plays up,take the door off you introduce a extra welter of air aps then makes and the fault goes,you can also use this method on a aps with a failing diaprahm

mikegas · Jan 3, 2011

so your just introducing more air to help create a greater + an - pressure, so if the venturi had melted and completely blocked removing the cover wouldnt help?

Billy Bob Bob · Jan 3, 2011

mikegas said:
so your just introducing more air to help create a greater + an - pressure, so if the venturi had melted and completely blocked removing the cover wouldnt help?

no,but if a bit had broken off,or in the modenas case broken and moved yes

mikegas · Jan 3, 2011

Cheers gas man

oldplumber · Jan 3, 2011

I first discovered about the venturis breaking at 4 oclock on a friday, luckily partscenter was nearby and had one in stock. live and learn all the time

Billy Bob Bob · Jan 3, 2011

bet you keep them in stock now old plumb, thermistors (white end) dont stay in stock with me long either,the likes of B.E.S ans antares sell these in packs of 10 but the venturies are a even bigger seller

Dannypipe · Jan 4, 2011

Quick update guys, I didn't get to this job again today as i had priority stuff come in (there central heating is still working after all!)

I bought the venturis, as well as APS, and high limit stat. I also spoke to Ferroli who seemed dead certain it was a blocked heat exchanger.

I'm going back tommorow to start trying things, starting with stat and venturis. I will as promised bring this thread to a conclusion so it might be helpful to other people in the future.

My phone just didn't stop ringing today. Its a love hate thing!

Dannypipe · Jan 5, 2011

Right, said I would bring this to a conclusion so I will! First pic is new part fitted in fan.

The boiler did run properly with the cover of. So I took the fan off, looked at the venturi, and visually what i could see looked fine. However I thought I'd remove it to get a proper look at it. The picture of the red crumbled thing is what happened!!

It had the texture of egg shell and fell apart. (Why don't they make them from metal?)

So I fitted the new one, and pushed the cover on, it tried running the hot tap, and it was consistently hot. Problem solved!!

The boiler still cycles during heating only, think this could be that it's so over sized....as I mentioned.

Big thanks to all who commented and I believe it was Gas Man that first mentioned the venturi, so double thanks to you. Client pleased as they don't have much cash and it was a cheap repair and a cheap component.

I injected some F5 into the system as they have a bathroom fitter there at the moment and he says he's happy to drain the system and put the inhibitor in it. The water is as black as the night. So I wonder if there is a slight blockage in the HE?

Anyway, they're happy, I'm happy, you're happy. Everyones happy!!

Danny

Billy Bob Bob · Jan 5, 2011

glad it worked out danny,a very weak part on all ferroli modenas and f30 f24,and my first suspect when i come across this fault if the waters black ch thermistor will not be long before it gives up,thats what this forums all about helping each other

stevetheplumber · Jan 5, 2011

gas man said:
it does not have a plate heat steve

that would rule that out then

stevetheplumber · Jan 5, 2011

gas man said:
glad it worked out danny,a very weak part on all ferroli modenas and f30 f24,and my first suspect when i come across this fault if the waters black ch thermistor will not be long before it gives up,thats what this forums all about helping each other

i agree with that sentiment gasman a lot of us dont get many boiler repairs and dont gain that depth of knoledge its great to have the means to tap in to others experience
some one should start a web site with the top five problems on popular boilers
actually the boiler manufacturers have access to the most common faults long before anyone else and should be forced to list them on their websites

Billy Bob Bob · Jan 5, 2011

i totally agree steve,about helping each other,what really winds me up is the manufactures,look at this thread from danny as a example ferroli were adamant it was the heat exchanger cost to buy £350 (twinpass so dear) and as i said it would be the venturies but they wont willingly give out the right advice because they want to rip you on spares,in this case danny would have more than likely replaced the boiler,so this forums invaluable

Dannypipe · Jan 5, 2011

True, client was saying that they would rather have a new boiler than put a £360+VAT part (PTS trade price?) in there boiler. I don't blame them. So a tenner on a component is a winner all round. I like to repair things, and not throw something thats perfectly good in the skip.

Also as I have said, why do they make the part from plastic? it looks like something from a Kinder Egg.

Its a good forum, and I come on here to help people and learn....so I now have this info saved in my noggin for the next time.

It kind of annoys me when people come on for advise and you get no feedback as to if it worked....fine if it didnt but if it did it's useful to post a quick message as it means the thread is available for others in the future.

I've used threads that are 3/4 years old in the past to get me out of a jam with all matter of things from boilers to laptops.

Billy Bob Bob · Jan 5, 2011

thank you for the feedback Danny,always appreciated to all of us on the forum,and i agree with what you say but people are people 2 pm,s this week thanking me for my help but last week none,we give advice for several reasons to help guys like us out,as you have asked and very capably sorted out,and( i may need your advice one day)and to help others(when we think they wont kill them selves)as it was pointed out to me the other day,this forum is growing and is already good but we dont settle for that on here we are the best,and if we cant ask each other(which we could not without the forum,could in the merchants but most are miserable gits) whats the point of the word colleague ?we are all learning all the time

jubbsie · Jan 7, 2011

My son repaired his ferroli fan motor circuit board £10 for part from electrical wholesaler.
Ordered part then told the order was cancled. So ordered board £170 next day delivery,
still needed another part £90 . Called in plumbco New ferrolli Boiler £320 how do they do it for that I asked , they make more money on parts.

ifgw77 · Dec 14, 2011

Hi All, I'm having the exact same problem; I believe it to be crap in the system. I was just wondering if anyone had the exchanger out on one for the best way to do it.
Thanks and Kind Regards, Ian

plum.bob · Feb 26, 2013

Hi, just wanted to say big thanks all you guys who take time to reply to these threds.
To Dannypipe, i had the same simptoms as you described. Beenscratching my head trying to figure it out, read this, done it, fixed it, customer well happy, and so am I at the gained knowledge.
Several plumbers just said replace fan/ heat exchanger/ circuit board and so on, others just said replace the boiler first as last.
Gas man your knoledge nows no bounds, many thanks.
Theres allways another way.

glenfruin · Jan 5, 2014

I would like to thank all that posted on here as I had they same problem with my boiler....i,m not a plumber but i used the advice and opened up the boiler and carefully vaccumed out the venturi and any other little hoses and pipes.then reassembled and it works perfectly now.no new parts req

thanks again

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