boiler condensate into cast iron drain

[RobertL]

This topic came up in another thread but I thought needed a wider discussion.

The condensate water from a condensing boiler is slightly acidic. Mine currently runs onto the ground pending a proper solution. I had planned to feed it into the plastic soil stack but that stack connects to an older cast iron pipe below ground level and that the drain below ground has lime mortar joining the ceramic pipe sections.

Is it advised not to allow condensate water into such a drain system? Will it really dissolve the cast iron and the lime mortar or are these urban myths?

Robert

[John Rumm]

Assuming it was just condensate, it might eventually cause _some_ corrosion of a soil pipe, but only over a *very* long time span.

The advice not to discharge it straight into a metal pipe applies mainly to the run from the boiler that will carry condensate and nothing else. Once it is mixed with other waste water it becomes a non issue. When you think about it, you stick a reasonable range of things down a drain that will vary in ph - so the occasional splodge of vinegar strength acid will be lost in the noise amongst the gallons of other crap (possibly literally!)

[RobertL]

A good point, thanks,

Robert

[1501]

Just out of interest, does anyone know the pH of crap?

[Dave Plowman (News)]

I'd guess your waste products would depend on the raw materials - same as any other chemical process.

[John Rumm]

I am sure the results of a good curry could rival and condensate drain!