Slight condensation from flue pipe

[Wooej]

I have a Vaillant Ecotec Pro 24 boiler which was installed a yer ago and which has been running normally since then.

Last week it was inspected under an extended maintenance contract and the chap said that there was condensation
from the flue pipe which could run down into the boiler and cause expensive repairs.
He said I should get someone in to re-fix the flue pipe (which is a short standard horizontal outlet through the attachment wall, and is horizontal.)
On inspection, the amount of water seemed to me to be less than a thimble-full - just enough to wet a small area.
He nonetheless signed the boiler off as OK - all readings were within their limits.

I would like to know where this water could have come from and what the implications are, if any?

Thanks for any advice,
John

 

[muggles]

You're not clear about which bit of the flue the condensation was in. If it was in the inner section this is perfectly normal. If it was in the outer section or inside the boiler it warrants further investigation, as there's a leak somewhere. If this was the case then he shouldn't have signed it off without rectifying it

 

[BARNY78BG]

You're not clear about which bit of the flue the condensation was in. If it was in the inner section this is perfectly normal. If it was in the outer section or inside the boiler it warrants further investigation, as there's a leak somewhere. If this was the case then he shouldn't have signed it off without rectifying it

agree with muggles, also some installers feel that condensing boiler flues have to rise to outside but this isn't always the case as some flues are designed that the exhaust part of the flue actually give s the correct rise inside the flue. so the flue itself should be dead horizontal. but if it is condensation then as mentioned ther could be a seal defective or a break in the exhaust part of boiler/flue and isn't always picked up on telegan readings

 

[Wooej]

Just to clarify: the small amount of water was found on the top of the boiler casing,
just in front of where the flue pipe comes out.
Unfortunately(?) there was not enough to tell where it might have come from.

John

 

[muggles]

Keep an eye on it and report back if it reappears

 

[twgas]

agree with muggles, also some installers feel that condensing boiler flues have to rise to outside but this isn't always the case as some flues are designed that the exhaust part of the flue actually give s the correct rise inside the flue. so the flue itself should be dead horizontal. but if it is condensation then as mentioned ther could be a seal defective or a break in the exhaust part of boiler/flue and isn't always picked up on telegan readings

some of the glowworm MIs say the flue should slope up to the terminal, in the same book it says the slope is built into the flue so should be fitted level

 

[BARNY78BG]

agree with muggles, also some installers feel that condensing boiler flues have to rise to outside but this isn't always the case as some flues are designed that the exhaust part of the flue actually give s the correct rise inside the flue. so the flue itself should be dead horizontal. but if it is condensation then as mentioned ther could be a seal defective or a break in the exhaust part of boiler/flue and isn't always picked up on telegan readings

some of the glowworm MIs say the flue should slope up to the terminal, in the same book it says the slope is built into the flue so should be fitted level

i know BONKERS REALLY

 

[BARNY78BG]

Just to clarify: the small amount of water was found on the top of the boiler casing,
just in front of where the flue pipe comes out.
Unfortunately(?) there was not enough to tell where it might have come from.

John

yeh mate, thats why the flue should be level, cos if rain water drives at the flue terminal and the flue is at an angle then, the rain flows back towards boiler via the air duct and then drips down through flue brackets and onto boiler casing!