Cross Contamination in a Gas Flue

FTimon

Hi
I have two Potterton gas boilers. I recently had them serviced. I was charged 450 euro to fix an external gas leak. He shut down the boilers on the basis I have cross contamination in both flues and repair cost 3-4 k to replace the 2 flues. The boulders were installed in 2010. Can the Flues not be resealed at the joints? Does this seem ok?

Dtp1979

FTimon wrote: »

Hi
I have two Potterton gas boilers. I recently had them serviced. I was charged 450 euro to fix an external gas leak. He shut down the boilers on the basis I have cross contamination in both flues and repair cost 3-4 k to replace the 2 flues. The boulders were installed in 2010. Can the Flues not be resealed at the joints? Does this seem ok?

Either your not explaining it right or your being screwed by a cowboy. What did he write on the gas cert he gave you when he shut down both boilers? Can you post pics of the flues and perhaps measure the distances between them?

FTimon

I no not think it is cross tamination between Flue 1 and Flue 2 but within each flue. Distance between them is 8-10 meters

Exact Language "Cross Contamination in Both Boiler Flues" this was in the notification of Hazard"

In the Declaration of Conformance:
Boiler 1: Flue Gas Analysis "Co 5774 ppm Co2 12.8% Co/Co2 Ratio 0.450
Boiler 2: Flue Gas Analysis "Co 484 ppm Co2 12.9% Co/Co2 Ratio 0.0038

FTimon

Wont let me post photos as i am a new user (FLue sticks about 9 inches to 12 inches out if the wall is black / round and in the flew part is about 6 inches

Wearb

Did you seek a second opinion?

FTimon

I have called another plumber but I would like to understand what the problem is.

Dtp1979

FTimon wrote: »

I have called another plumber but I would like to understand what the problem is.

Keep us updated. What plumber 1 is saying is that the flue outlet gas is mixing with the air intake. Very unusual that both boilers failed though. Did he hand you a printout of the flue gas reading ?

roy rodgers

What fuel are you burning?
I wonder if the boilers have been converted

Dtp1979

roy rodgers wrote: »

What fuel are you burning?
I wonder if the boilers have been converted

Well spotted Roy. I'd say that it!

FTimon

LPG

roy rodgers

FTimon wrote: »

LPG

That's the problem I'd say.

The boilers haven't been converted from natural gas to lpg.
They could be still done by a GOOD rgi. But I have seen boilers that weren't converted do a lot of damage to the boiler it really depends on how long they have been that way..
What make of boiler are they?

FTimon

Potterton promax Combination He plus. They have been running for 5 years. The last guy who serviced them never said . But not sure if he had a gas analyser

roy rodgers

FTimon wrote: »

Potterton promax Combination He plus. They have been running for 5 years. The last guy who serviced them never said . But not sure if he had a gas analyser

Them boilers come from the factory set up to burn natural gas and I don't think you can adjust the gas valve on them just looking at the manual there.
There should be a data badge on the boiler some where, it could be on the underneath of the boiler. It will tell you what gas it is set up to burn on that.
Under no circumstances you should use them boilers if that's the case. I know it's been working away for the last 5 years but it only takes seconds for that amount of carbon monoxide to kill you.
The problem I came across with boilers burning lpg that haven't been converted was that they burn a lot hotter and I have seen flues melt from the inside out heat exchanger buckle the frame also buckle and it turned out that it be cheaper to change the boiler than try and replace the parts.
Now that was the most extreme but that what happens

Dtp1979

It's frightening that this hasn't been spotted by an Rgi yet.

Wearb

It is also frightening that the last guy was so confident in his misdiagnosis that he was willing to have the op spend €3,000 or €4,000 to fix a problem that probably doesn't exist.
Even after spending that amount, the problem would still have been there.

jimf

I don't do gas as all on here will know but this is scary reading

FTimon

The two boilers are LPG so that not it

roy rodgers

FTimon wrote: »

The two boilers are LPG so that not it

Whats on the data badge? If you could post a picture of the data badge it would really help.

FTimon

Sorry i can not post photos as i am a new users

on the tag with bar code and serial number it is labeled

"Potterton Promax Combi 24 HE Plus LPG"

FTimon

Hi Folks - the Label on the boiler is :"Potterton Promax Combi 24 HE Plus LPG". This is part of the tag with serial number and and bar code.

roy rodgers

Ok we'll go with that.
On the flue gases printout what is the O2 at and what is the excess air at?

On position of the flues is there anything obstructing the flues would they have a min clearance of 600mm from walls hedges or balconies

FTimon

Roy Thanks

Obstruction: Flue 1 None Flue 2: when bushes grow and have leaves within 600mm but just about.

Flue 1: (intake O2% 19.5 - XS Air % ####.#) (Combustion O2 1.5% - XS Air% 7.5)
Flue 2: (Intake O2% 16.1 - XS Air % 335.9) (Combustion O2 1.4% - XS Air % 7.2)

FTimon

PS The temperature was set to max also

roy rodgers

There's not enough air for full combustion.
It's starting to look like the flues are a problem with the air intake well under 20%
Now I'm wondering if the right flues were used. Ones for condensing boilers and not ones for SE boilers.
There is a reason for the cross contamination and the rgi should be able to explain why it's happening before the 3 to 4k quote.
If it is the flues they can be replaced without to much hassle.

Are the flues going directly off the boiler to the outside individual?

FTimon

The boiler with worst readings is about one meter directly to the outside, with one 90% Bend. The second one is about two meters. I would have assumed the replacing a flue would not be that expensive. Waiting on a second plumber for another quote. Pity i cant post photos of the flue

Wearb

You can post photos by uploading them to Dropbox or Facebook etc. and providing a link here. You will have to manipulate the link, so that it doesn't look like a link. Eg put in a dash instead of a dot or PPP instead of www. You will get the hang of it.

FTimon

Folks thanks for the help todate - I am still waiting on the second Plumber he was to be here on Friday but must have got delayed.

I have tried to post a link to photos using multiple methods but will not work

1- I notice that when the steam/Fumes are coming out, it can blow down by the intake. In the manual i see options to separate the air intake and the exhaust

Also there is a joint on the Flue the looks corroded (a ring of metal) I assume this is not a standard part (Sorry have been looking at the manual)

Would these not be why there is cross contamination?

Hopefully i will get a more reasonable quote from the second plumber.

As there is not enough air intake - would a new / repaired flue improve efficiency ?

Dtp1979

FTimon wrote: »

Folks thanks for the help todate - I am still waiting on the second Plumber he was to be here on Friday but must have got delayed.

I have tried to post a link to photos using multiple methods but will not work

1- I notice that when the steam/Fumes are coming out, it can blow down by the intake. In the manual i see options to separate the air intake and the exhaust

Also there is a joint on the Flue the looks corroded (a ring of metal) I assume this is not a standard part (Sorry have been looking at the manual)

Would these not be why there is cross contamination?

Hopefully i will get a more reasonable quote from the second plumber.

As there is not enough air intake - would a new / repaired flue improve efficiency ?

You need 50 posts to put pics up. You have 15. Go on and post 35 smiley faces on other threads

roy rodgers

Is the inside of the flue plastic or metal?

FTimon

Plastic all plastic - it is exactly like the one in the manual for horizontal flue except this joint. (I am posting on other forums so i can put up photos.

FTimon

Roy thanks a million by the way

FTimon

https://www.dropbox.com/sc/e2t4mvzokm7cuef/AADZmqwkJ5y4n82HYHzrlAbWa

FTimon

ps it must be 25 posts to put up photos

FTimon

https://www.dropbox.com/sc/zhvko0ttclfpqp1/AABuA9uD6aRlABGiBYhF33V3a

full set of photos

Wearb

Post one that has both flues in the one photo

FTimon

The flues are 10 meters apart I can't get them in one photo

DGOBS

Boiler 1: Flue Gas Analysis "Co 5774 ppm Co2 12.8% Co/Co2 Ratio 0.450
Boiler 2: Flue Gas Analysis "Co 484 ppm Co2 12.9% Co/Co2 Ratio 0.0038

Has anyone tried adjusting these boilers? Co2% is very high even for LPG? (as stated below air is very low) Hi fire readings should be 10% Co2 (9.5% on low fire)
so way out.

First step is o have RGI carry out an air intake contamination test, air should not be below 20.6% in readings (ideally 20.9%) this will rule out cross contamination (or not) if readings show <20.6 and there is also Co2 and Co on same sample, then there is a flue issue.

If not and readings are >20.6% then the issue in the appliance, gas settings, combustion chamber seals, burner, etc, etc, all items require checking. The gas adjustment as per manufacturers instructions.

FTimon

O2 intake on boiler 1 19.5
O2 intake on boiler 2 16.1

hope plumber comes today

roy rodgers

Every thing is looking good in the pics anyways nothing out of the ordinary..

Because the air in take is reading way out I'd say the flues will need changing. Definitely won't cost 4k!!!

Keep us up dated with the next plumber.

Dtp1979

If the original installer used something oil based like wd40 on the flue rubbers then at this stage the rubbers could be rotting and allowing the cross contamination. It'd explain why both are failing at the same time. It can't be a coincidence.

FTimon

update. Next plumber kept me waiting. Now he says he is too busy. Got another but he says he does not replace flues but disconnect the boiler. He recomended someone and he wants a commission cert before he starts. I do not have one. RGI say cents were not needed In 2009 and ther would not be one. The contractor who installed it is gone out of businesses.

Any recommendations

roy rodgers

FTimon wrote: »

update. Next plumber kept me waiting. Now he says he is too busy. Got another but he says he does not replace flues but disconnect the boiler. He recomended someone and he wants a commission cert before he starts. I do not have one. RGI say cents were not needed In 2009 and ther would not be one. The contractor who installed it is gone out of businesses.

Any recommendations

What part of the world are you in.? One of us around here might be able to help

FTimon

Galway city

FTimon

Folks
Still without heat - have paid over 500 euro so far and no boilers working - Am i doing something wrong? Rang another two plumbers and they won't return calls.



Feargal

roy rodgers

FTimon wrote: »

Folks
Still without heat - have paid over 500 euro so far and no boilers working - Am i doing something wrong? Rang another two plumbers and they won't return calls.



Feargal

I feel for ya feargal. We can't the staff either here up in Dublin. Try the rgii Web site to see if there is local lads around.