Acidic condensate and salt glazed pipes?

[Donkmeister]

I have had a few companies out to quote on a new heating system for my house. A question none of them have been able to answer is... Is the condensate from the boiler likely to cause harm to my salt-glaze drainpipes or the cement joining them?

I've googled but the only sources I found seem to be selling neutralisation tanks so obviously they claim that acidic condensate will destroy everything. I've also read a few sources claiming that condensing boilers are rarely running in condensed exhaust so presumably there is very little condensate (for better or worse).

So, has anyone actually had salt-glaze drainage compromised due to boiler condensate?

 

[muggles]

If in doubt, neutralise. Condensate can be produced at a couple of litres an hour, and should be produced most of the time if the boiler has been installed and commissioned correctly

 

[denso13]

So, has anyone actually had salt-glaze drainage compromised due to boiler condensate?

No, dont worry about.

 

[Steelmasons]

Obviously the condensate will be neutralised considering the function of the pipe in question....
You got a be kidding right??

 

[Hugh Jaleak]

I'd be more worried about concrete pipes, but there wont be any of those in 4 or 6" size, so I think you'll be fine. Depending on where the condensate enters the system, by the time it mixes with water from other sources, it'll be too weak to be of any consequence anyway. I've seen a concrete sewer destroyed by a constant flow of acidic water from a factory manufacturing wheat starch, but that was a constant flow, 24/7. It was replaced with a vitrified clay sewer, which, hopefully, will cope better with the nature of the effluent from the factory.

In all honesty, I'd think Hydrogen Sulphide (found in drains) would be more of a problem in attacking the pipework etc.

 

[Agile]

Most older houses have s.g. clay drainage and all boilers are connected to that.

But I have never heard of any damage like that.

The condensate is very weakly acidic. Probably no more than tea which can be 4.9 pH !

Different quotes are given for boiler condensate of for example 2.9 to 4.0 or 3.0 to 5.0. But the main point is the boiler condensate is not very acidic at all.

A friend of mine had a boiler cheaply fitted by an East European who used 22 mm copper pipe for the condensate. Seven years later its still working fine.

Tony

 

[Nige F]

Apparently the pH of condensate is 3.9 - 4 . The cement joining salt glazed should be a 1:1 ratio with sand, with a small jointing area exposed ( or hidden by a turn of tarred gaskin) depending on the age of the installation. Urine varies between 6.5 -8 . Washing up liquid is 7 -8. Pure water is 7 so I'll leave the maths to the P takers.

 

[JohnD]

I've dug up a few salt-glazed pipes, but none that have had condensate down them for 20 years.

However I did previously have a neighbour whose flue had been dripping on the concrete paving beside his house for that long, and it had eaten into the slab directly underneath, leaving a hollow of grit and stones which they swept away.

This led me to put a hanging basket on the wall under mine.

 

[Donkmeister]

Thanks all, seems I was worrying over nothing - thought that might be the case.