Calling all CORGI boys (Ariston Boiler issue)

[richydraper]

woke up this morning to a very cold house and no hot water
i have an Ariston MicroGENUS 27 MFFI Combi boiler and the Yellow 'fume fault' LED was illuminated. the user manual says this:-

The boiler is fitted with safety devices, which in the event of a defective discharge of exhaust fumes, automatically interrupts the gas supply, thereby shutting off the boiler. The shut-off of the boiler is temporary and is indicated by the illumination of the yellow L.E.D. for a period of about 15 minutes. Once this time period has passed and the discharge state of exhaust fumes has returned to normal, the boiler automatically turns back on.

thing is... it doesn't.

ive checked water pressure in the CH circuit(1.7bar), the CH pump works, ive checked operation of the Air Pressure Switch (by sucking and blowing the hose connecting it to the fan housing) and can hear it operating. the thing seems to be failing to attemp to supply gas and ignite it. yet the pump for the CH still works as it should (i.e. with signals from the thermostat)

-BUT-

i turned it off at the wall and left it for 90mins turned it back on. it fired and heated the CH to 40* for maybe 60 secs, then made a buzzing sound and shut off, illuminating the 'fume fault' LED again.

ive tried to do research on it but obviously due to it being a boiler and legally CORGI are only allowed to service/repair it ive not come up with much. i'm certainly not bridging wires to make it think everything is as it should be, as i do actually quite look forward to waking up tomorrow.

now for the bad news
i have no history of it ever being serviced (i haven't in the 5 years i've lived here ) which tbh i REALLY should have done.
i dont know its exact age (production was between 1999 and 2007).
i dont have Boiler/central heating insurance.
oh and im absolutely skint and can't afford a call out charge let alone repair costs on top, but could probably stretch to the suspect part if i knew what it was.

dunno if these will be of any help...
View attachment Ariston MicroGENUS 27 MFFI Install Instructions.pdf
View attachment Ariston MicroGENUS 27 MFFI Service Instructions.pdf
View attachment Ariston MicroGENUS 27 MFFI User Manual.pdf

 

[tim1989]

Get it serviced the gas to air Mix is wrong! Stop trying to use it

 

[richydraper]

Get it serviced the gas to air Mix is wrong! Stop trying to use it

cheers timbo! Is adjustment of the 'AFR' included in service costs?

 

[tim1989]

Yes its one of the main parts of a service

 

[richydraper]

nice one buddy, puttin my feelers out trying to find a friend of a friend

 

[richydraper]

well after 3 weeks of living in a damp cold house i finally got it sorted!
turned out it was the Fan control relay on the PCB... 3 plumbers told me it was time for a new boiler with prices all upwards of £1500. i gave up and stumped up £50 for an 'emergency' plumber to come out who said the PCB was goosed and would get back to me with a price... he never did so i scouted around for hours on google and a PCB would cost me £150... that was still too much so since the PCB was coming out anyway i thought id have a look and see if it was repairable. it was and i ended up putting a £2.60 relay in it. job jobbed until a couple of weeks ago!

now shes loses pressure through the PRV every time the CH fires up meaning i have to top it up via the filling loop to keep pressure in her.

after the CH has been running and the water temp cools the pressure drops to below 0bar, i top her up to 1.5bar. when the CH turns on again the pressure rockets to 3bar and the PRV opens dumping excess pressure out of the little pipe outside my back door.

so im in 2 minds as to the fault. most of my money is on the expansion vessel though good news is its summer soon and i can deal without CH or hot water for a few months! i have read in various places that it could be the PRV at fault but since it only operates at pressures around 3bar i dont think this is at fault.

can anyone confirm/deny

 

[EvoStevo]

I turned my heating off last week.

I know what your on about with the relay though, I had a WB combi boiler that went after a few years, had 3 CORGI guys looking at it (its no longer CORGI now though) and they could not figure it out.
Turned out to be the fan relay contacts goosed, ended up changing that relay 3 times over the life of the boiler. Rewound the fan twice because water got in via the flu and caused the windings to short.
Seems the corgi engineers are great at the gas side but not so much on the electrical side.

Now you need to ask for a "Gas Safe" engineer.

 

[Davren]

now shes loses pressure through the PRV every time the CH fires up meaning i have to top it up via the filling loop to keep pressure in her.

after the CH has been running and the water temp cools the pressure drops to below 0bar, i top her up to 1.5bar. when the CH turns on again the pressure rockets to 3bar and the PRV opens dumping excess pressure out of the little pipe outside my back door.

so im in 2 minds as to the fault. most of my money is on the expansion vessel though good news is its summer soon and i can deal without CH or hot water for a few months! i have read in various places that it could be the PRV at fault but since it only operates at pressures around 3bar i dont think this is at fault.

can anyone confirm/deny

Had the same with mine last year, the schrader valve on the expansion vessel was leaking, allowing the vessel to fill with water. On the microGENUS it's on the top of the vessel at the back. Couldn't get the valve out with a normal car cross type valve tool, it's too close to the wall so you need a straight handled tool.

 

[poggy]

It's probably the diaphragm in the expansion vessel. Basically it is half air half water and the diaphragm moves to compensate for extra volume as water expands when heated. If a hole develops it fills with water and then when it heats the excess volume goes out of the PRV. When it cools you have less volume and no pressure. Sometime it means taking half the boiler apart to replace it.

The engineer who replaced ours fitted a remote vessel by a radiator upstairs, but you can put them in the cupboard under the boiler apparently if there is one.

You really should get a proper engineer to do it and service the boiler at the same time. British gas do a fixed price repair thing.

 

[richydraper]

Had the same with mine last year, the schrader valve on the expansion vessel was leaking, allowing the vessel to fill with water. On the microGENUS it's on the top of the vessel at the back. Couldn't get the valve out with a normal car cross type valve tool, it's too close to the wall so you need a straight handled tool.

gotta be worth a try any idea of the pressure required to make her good Davren?

It's probably the diaphragm in the expansion vessel. Basically it is half air half water and the diaphragm moves to compensate for extra volume as water expands when heated. If a hole develops it fills with water and then when it heats the excess volume goes out of the PRV. When it cools you have less volume and no pressure. Sometime it means taking half the boiler apart to replace it.

The engineer who replaced ours fitted a remote vessel by a radiator upstairs, but you can put them in the cupboard under the boiler apparently if there is one.

You really should get a proper engineer to do it and service the boiler at the same time. British gas do a fixed price repair thing.

ive heard about these remote vessels my boilers in a pretty discreet place anyways so placement wouldnt be an issue... i probably should get a proper engineer in to do it but from looking at the exploded views of the boiler i might be able to get away with not touching gas side... if i do end up having to dismantle gas bits ill be getting a guy in to turn off and turn back on the supply before/after ive done the work.

ive lost ALL faith in supposed 'professionals' (due to the fact that 4, from reputable companies, couldnt pin point my issue. and ive seen the shocking handywork of british gas at my parents house, the guy couldnt even solder pipes together without them leaking not so Gas Safe!!!) hence i will be doing the work myself! its only nuts and bolts and pipes and unions... something that working with trucks ive become accustomed to. if it was out of my depth i wouldnt even consider it but im not writiing some apparently 'qualified' monkey a blank cheque for something that will take me maybe 2 hrs tops!

 

[poggy]

I think they are about £55 for the proper one and the remote kit was £45 kit from memory.

The remote one is just a in/out connection, so you just tap into the radiator feed and put it inline.

I was thinking a service is good for safety as they measure the combustion gases etc. We use Npower I think who charge about £6-7 a month for a annual service.

 

[Davren]

gotta be worth a try any idea of the pressure required to make her good Davren?

Pumped mine up to 1 Bar while the dry side of the diaphragm was at 0 bar. You may need to drain some water off until the pressure gauge reads 0 Bar.

Loosen the Schrader valve, or just press the pin in. If water comes out, then the diaphragm is leaking so you'd need a new one anyway. I'm not sure if a new one comes pre pressurised.

The microGENUS expansion vessel is disc shaped and just under 400mm diameter. It comes out the top of the boiler, so, because you can tilt it, you'd need slightly less space than that above the boiler to get it out without disturbing the boiler.

There's just a small water pipe attached to the bottom of the EV, so unless you need to move the boiler to get it out, you don't need to interfere with any gas connections.

 

[richydraper]

I think they are about £55 for the proper one and the remote kit was £45 kit from memory.

The remote one is just a in/out connection, so you just tap into the radiator feed and put it inline.

I was thinking a service is good for safety as they measure the combustion gases etc. We use Npower I think who charge about £6-7 a month for a annual service.

ill be getting it serviced when im done and in the off season for the boiler guys. figured i might actually be able to find one in the summer, rather than waiting for nearly a month for anyone to even turn up!

Pumped mine up to 1 Bar while the dry side of the diaphragm was at 0 bar. You may need to drain some water off until the pressure gauge reads 0 Bar.

Loosen the Schrader valve, or just press the pin in. If water comes out, then the diaphragm is leaking so you'd need a new one anyway. I'm not sure if a new one comes pre pressurised.

The microGENUS expansion vessel is disc shaped and just under 400mm diameter. It comes out the top of the boiler, so, because you can tilt it, you'd need slightly less space than that above the boiler to get it out without disturbing the boiler.

There's just a small water pipe attached to the bottom of the EV, so unless you need to move the boiler to get it out, you don't need to interfere with any gas connections.

how come you know so much about the microGENUS... have you got one?

thank you both for the info!!

 

[Davren]

how come you know so much about the microGENUS... have you got one?

Yeah... 23MFFI.

I fitted it 9 years ago and apart from the Schrader valve and one of the filling loop tap spindles leaking, it's been perfect.

 

[ChrisUK]

the diaphragm has gone in mine and is doing exactly the same. I 'was' going to replace the boiler but apart from that issue it's been faultless so far. I've been living with it by manually pressurising it etc but i'm getting sick now.

 

[richydraper]

Yeah... 23MFFI.

I fitted it 9 years ago and apart from the Schrader valve and one of the filling loop tap spindles leaking, it's been perfect.

haha the little brother of mine
apart from the relay (direct replacement available from RS) and this EV issue mines been pretty faultless in the 5 years Ive been here even If i havent serviced it...

the diaphragm has gone in mine and is doing exactly the same. I 'was' going to replace the boiler but apart from that issue it's been faultless so far. I've been living with it by manually pressurising it etc but i'm getting sick now.

Ill pm You a parts website If You fancy havin a go yourself

 

[Davren]

I've been living with it by manually pressurising it etc but i'm getting sick now.

Continually topping it up with water will reduce the corrosion inhibitor concentration.

 

[richydraper]

*adds corrosion inhibitor to his shopping list*

 

[ChrisUK]

Continually topping it up with water will reduce the corrosion inhibitor concentration.

Yeah I realise that. I'd be surprised if it had any left tbh .

 

[GrandeGuy]

I don't think i can legally post in this thread
This is the best and probably the cheapest option for you.
http://www.britishgas.co.uk/product...d-central-heating/one-off-boiler-repairs.html
But I'll leave you with two thoughts,

1, if your vessel has gone and your Flue pipe goes out the back, or you have less than half a meter clearance above the boiler, the whole boiler will have to come off the wall (my best time is 3hrs and 27mins to remove and rehang) to fit a new vessel!

2,You don't have to fit a remote vessel where the boiler is fitted, as long as it's on a flow or return pipe somewhere and cant be isolated . . . .

Also for anyone out there with vessel problems/pressure problems if you 3/4 drain a rad of water (one you don't use) this will act as as a temp vessel and take up the expansion.