Horizontal flue on sloping roof

[gassed up]

Been to a breakdown job with this type of flue, this one is reading very high combustion products after fitting a new gas valve.

Looks like there must be a bad seal in the flue system as co is being drawn in with the air supply.

Anyway, I have been asked to quote on repairing or replacing the flue and i am in two minds whether to get involved, obviously this type of flue installation is not specified or advised by any of the manufacturers, it will need to be replaced like for like, but will be safer after the work than it is currently.

Would be keen to hear others views on this situation.

Cheers

 

[ShaunCorbs]

Worcester ideal and vaillint have guidance in there flue book ok but must be 300 mm from bottom of tile to end of flue on the bottom

 

[gassed up]

Should have said it's a Baxi. But didn't realise those other mf's allowed it.

There looks like there is 300 below this one, but haven't gone up the roof to measure it and that's the other thing I would have to take a chance that I could do the whole replacement from the inside, as not going to take the risk of walking up the roof and cracking tiles etc.

 

[ShaunCorbs]

I would pass if your not going on the roof

But there a chance you won't get paid as you would have to cap the appliance

You done a flue integrity check ?

 

[ambrosia]

did you check the air intake, oxygen levels should be about 21, if its got co or co2 in there then you know for sure its a seal somewhere on the flue

 

[gassed up]

did you check the air intake, oxygen levels should be about 21, if its got co or co2 in there then you know for sure its a seal somewhere on the flue

"Looks like there must be a bad seal in the flue system as co is being drawn in with the air supply".

 

[gassed up]

I would pass if your not going on the roof

But there a chance you won't get paid as you would have to cap the appliance

You done a flue integrity check ?

Sorry mate didn't realise you had posted this.

I have been back and dismantled the flue and changed the seals but still getting products at the air intake test point. The original seals were flat but didn't seem that bad or damaged and the exhaust pipe appeared to be in sound condition.

My thoughts now are that the seal between the heat exchanger and flue adaptor might be leaking, causing the products to rise up around the air intake.

I am still getting co at the air intake test point with the outer combustion cover off, so i can't see how it is being pulled down the flue, surely the fan would sucking air from the room.

When you say flue integrity check, do you mean using a pellet?

 

[ShaunCorbs]

Np

Shove your probe as far in as you can with the cover on if you detect co something not right

If you have your probe 2" past the bend joint then it can be the case flue seal