dripping flue

[stevetheplumber]

any flue dripping condensate is ID in my eyes if the condense can escape the flue isnt sound you wouldnt leave a bbu running if it failed a smoke test with smoke escaping from the flue internally

 

[GrahamM]

Although is an old thread got to agree 100% with steve.
If a flue is dripping condensate internally the flue is not sound. If can drip condensate it is possible that could spill combustion gasses.
Clear ID in my opinion!

 

[Chris Kafetzis]

I too agree with ID, also I've come across 4 vaillant boilers with this problem, twice on my own installations. I always file down the edges of the inner flue and use silicon grease on rubbers. Recently however I went to service a boiler I fitted 3 years ago with this problem. When I rang vaillant they wouldn't do anything because apparently vaillant don't make there own flue so it's not covered in the warranty! I feel short changed really, this is clearly a manufacturing fault in my eyes. The seals had shrunk and wrinkled up, then the condense had rusted a clear hole in the side of the flue that I could fit my finger in! Might start with Worcester soon I think.

 

[Anton]

I too agree with ID, also I've come across 4 vaillant boilers with this problem, twice on my own installations. I always file down the edges of the inner flue and use silicon grease on rubbers.

According to the installation manual for the Air/Flue Gas System supplied by Vaillant:

"Mineral oil-based lubricants may damage the seals. The seals should therefore not be lubricated.
Only use water or commercially available soft soap, if necessary, to assist with the installation."

 

[kris]

Its an old post but defo I D as if pipework sagging / dripping condensation then its not supported properly so Deco I'd. . If it hadn't been sagging and was supported then I would've A R it.

 

[GrahamM]

According to the installation manual for the Air/Flue Gas System supplied by Vaillant:

"Mineral oil-based lubricants may damage the seals. The seals should therefore not be lubricated.
Only use water or commercially available soft soap, if necessary, to assist with the installation."

As mentioned an old post.
But, going back to my chemistry days silicone grease is a fairly safe lube to use on rubber and fairly non-reactive. If anything it protects the rubber.
I use it daily for seating all seals & until anyone comes up with any substantial proof that it now has a detrimental effect on rubber I will continue to do so.


Just don't use any hydrocarbon based lube! e.g. Vaseline

 

[GasmanxxxR1]

Went back to a boiler that i installed 4 years ago, baxi solo with a long plume kit. Water was leaking from the case. When i undid the combustion chamber it was FULL of water, the fan had nearly drowned!. In the end i found it was condensation from the inner flue leaking from the seal of the elbow on top of the boiler. it had completely perished, it was just blue mush.

I installed it and I know I only use silicone grease or nothing at all. What could make the seal perish like that?

 

[bigads28]

Went back to a boiler that i installed 4 years ago, baxi solo with a long plume kit. Water was leaking from the case. When i undid the combustion chamber it was FULL of water, the fan had nearly drowned!. In the end i found it was condensation from the inner flue leaking from the seal of the elbow on top of the boiler. it had completely perished, it was just blue mush.

I installed it and I know I only use silicone grease or nothing at all. What could make the seal perish like that?

That seal is of pretty poor quality, must be a combination of heat and the condensate. I've found that if your combustion readings are high or you spot water in the case then its usually from that seal. If you don't catch it soon enough it wrecks the heat exchanger.

 

[thorn]

GasmanxxxR1, Just wandering how these faulty flues were resolved with customer, did they pay for replacement or try to point fault at you.
shocked to hear vaillant don't cover flue under warranty - abit **** to say the least

 

[kirkgas]

ID all day long, by seeing fluid he has confirmed the flue isn't sealed