Repair gas boiler external vent.

sonny liston

Hi folks,

the gas boiler of my central heating system at home has an exhaust pipe.
The pipe goes from the boiler through the external wall to the outside world.
The pipe extends horizontally about 20cm outside from the wall.
Outside, there is a larger diameter metallic pipe encasing the exhaust pipe. I assume it is there to protect the exhaust pipe.

After 7 years, the larger pipe now has rust on it, and even a small hole.
Any tips on how to repair the small hole and protect the pipe from future damage?

Do I need to be wary of anything since it is part of the gas boiler?

Cheers.

slimjimmc

Based on your description imo it's nothing to panic about boiler-wise, the inner pipe carries the exhaust gasses while fresh air needed for combustion is sucked in through the void between the inner and outer pipes. A small hole just means a little more air can be sucked it but I doubt it will upset the efficiency of the boiler.
I'd just treat any rust and paint, it doesn't get hot so high temp paint not needed.
As always if in doubt ask an RGI.

Strange how it corroded so quickly. My boiler flue is 10 yrs old, the paint is flaking but there's no corrosion and looks to be galvanised.

Dtp1979

Do not attempt to work on a gas flue irregardless of whether it's the air intake or not. The corrosion you're seeing might extend further into the wall. The inner pipe might also be corroded. Get an Rgi out to look at it, have the boiler serviced which will also include a flue gas analysis performed.

sonny liston

Cheers folks.
The boiler was serviced a couple of months ago, and it was the RGI engineer who pointed out the corrision to me and suggested I paint the flue.
There is only a small bit of corrosion away from the wall, at the end of the pipe.
There is a small hole about the size of a 1 cent coin.
The inner pipe is fine.

I think it's very minor thing, am in two minds whether to get RGI or fix myself?

How do you patch a small hole in a metal pipe like this?

sonny liston

The boiler and flue analysis were fine at last service 2 months ago.

Dtp1979

sonny liston wrote: »

The boiler and flue analysis were fine at last service 2 months ago.

On the flue gas analysis that was on the gas cert, what were the 3 readings written down on it. Co, co2 and the ratio

sonny liston

Co: 12 ppm
Co2: 4.3%
Co/Co2 Ratio: 0.0003

Dtp1979

sonny liston wrote: »

Co: 12 ppm
Co2: 4.3%
Co/Co2 Ratio: 0.0003

It's burning safety so. But you still, by law, can't work on a gas appliance yourself. it must be an Rgi doing the work.