Where's my black grit coming from?

[jshailes]

I have a condenser bolier and have heard that black grit can accumulate in the condense outlet pipe. The reason I've been looking into this is that the copper pipe into the waste pipe is blocked with grit and I'm guessing it must have been either a reaction with the copper or a product of the boiler. Has anyone experienced this before?

 

[ianniann]

Maybe your heat exchanger is dissolving? The condensate shouldn't be running into a copper pipe anyway, that isn't going to last.

 

[powell30]

Most black 'grit' is the sloughing off of aluminium deposits from the inside of ali heat exchangers.

Not seen this as much if at all on stainless.

It should be flushed out on your first service and isn't a problem unless it's a massive amount. PLASTIC should be used for condense runs

 

[Boilerman2]

You don't say what make and model boiler you have, but has already been said, Aluminium heat exchangers do give rise to this problem, certain makes and models do it more than others, but as long as the condensate trap is dismantled and cleaned at each and every service (12 monthly) then this should cause no problem

 

[simond]

I find the aluminium heat exchangers fill up with a grey slurry, which is to be expected to a degree.

The stainless Giannoni (as per Baxi, MHS, Alpha, Vaillant, Glowworm, ecoHometec, Remeha etc) tend to discharge black grit.

Interestingly, the Viessmann stainless is normally almost clean.

Draw your own conclusions......