Condensing boiler - Told I cannot have as Cast iron Waste pipe - True???

Hello there,

I had three quotes to have a combination "Condensing" boiler fitter. First two looked it and said fine and provided price. However, the last guy and the one who I liked most said I cannot have a combination condensing boiler as I have a cast iron waste pipe which is shared with the whole flat (I am on top floor of three story flat). He said the high acidic content will rot the sewage pipe and I am not allowed.

No one else mentioned this! Even the inspector (it is an ex authority property) who visited for other aspects did not mention this (although he was not particular an expert).

Looked on the internet and cannot find any mention of this. Anyone else heard this?

Kind regards Dave

Reply to
Dave Smithz
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True. If there is dilution from the point of entry into the CI soil & vent pipe, then there probably won't be any significant corrosion. It will rot a CI drain pipe if there is inadequate dilution, it will rot the bottom out of a horizontal pipe. .

See 'Condensate Treatment', P22 of this document.

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Reply to
Aidan

I used Unibond bathroom and shower sealant from the local shed. Expensive at 8 quid a go but it's so bloody waterproof it's v.difficult to smooth it after application 'cos it sticks to

*everything*. Flexible too, the only thing that broke it in our case was for some reason the shower tray managed to drop a few mm (don't ask why, I dunno yet!) and the stuff stretched and broke the grout on the surrounding tiles resulting in much leakage.....

The moral to this tale is if yer tray doesn't drop this stuff is good! IMO obviously.

cheers

witchy/binarydinosaurs

Reply to
fred

I used Unibond bathroom and shower sealant from the local shed. Expensive at 8 quid a go but it's so bloody waterproof it's v.difficult to smooth it after application 'cos it sticks to

*everything*. Flexible too, the only thing that broke it in our case was for some reason the shower tray managed to drop a few mm (don't ask why, I dunno yet!) and the stuff stretched and broke the grout on the surrounding tiles resulting in much leakage.....

The moral to this tale is if yer tray doesn't drop this stuff is good! IMO obviously.

cheers

witchy/binarydinosaurs

Reply to
Andy Hall

OK, thanks for the input. This has left me slightly confused as what to do though as I am not really sure whether this guy is right or not. I had 4 guys come round - 2 gave a good look round, two a quick look round. One of the two who had a quick look mentioned this cast iron pipe detail.

Could it be that he justs wants an easier job of fitting a non-condensing boiler?

Is the conclusion then that I should not be dischargin into a cast iron waste pipe and therefore cannot have a condensing boiler?

Any more opinions welcome.

Kind regards

Dave

Reply to
Dave Smithz

I used Unibond bathroom and shower sealant from the local shed. Expensive at 8 quid a go but it's so bloody waterproof it's v.difficult to smooth it after application 'cos it sticks to

*everything*. Flexible too, the only thing that broke it in our case was for some reason the shower tray managed to drop a few mm (don't ask why, I dunno yet!) and the stuff stretched and broke the grout on the surrounding tiles resulting in much leakage.....

The moral to this tale is if yer tray doesn't drop this stuff is good! IMO obviously.

cheers

witchy/binarydinosaurs

Reply to
Ed Sirett

Apart from possible regulatory considerations - Tee-ing into a CI soil stack whilst possible is not easy. As I would look hard at other routes first.

The exemption procedure gives extra points if there is no practical way to make a condensate drain - However, off the top of my head the procedure means that you still need extra points for a semi even after you have decided to move the boiler - unless the flue or condensate drain are _even then_ still no practical.

Reply to
Ed Sirett

Possible.

have a look at

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describes the assessment procedure and also some installation advice.

The exemption scoring section does not take the material of the condensate drain into account.

There is an oblique reference in the section about materials which mentions not using copper or mild steel.

However, it does also mention a soakaway as an option if there isn't a suitable drain or gully.

In short, if you don't want a condensing boiler, then an installer may be willing to fill in the paperwork (tick box Y and give a reason) to justify that it was not practical.

If you do, then there may be another way than to use the CI pipe.

Reply to
Andy Hall

Limestone? With the acidic condesate that will eat it's way through metal pipes. Doesn't sound right to me, give it a few years and you'll just have a hole in the ground...

Reply to
Dave Liquorice

I think that that's the point.

The limestone is intended to neutralise the acid.

Hepworth make a plastic soakaway product for the purpose.

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also to ODPM document.

Reply to
Andy Hall

The Viessmann link above also shows a neutraliser. You can get marble chips for landscaping, which would do.

Can't you run the condensate in plastic down one floor below, or into, a waste from a wash-basin or bath? The waste water should then dilute the condensate enough to avoid a problem.

Reply to
Aidan

Good point. B-)

But the first link says that the limstone chippings are outside the soakaway so no means of replenishing them without digging out the soakaway. Now if they where inside with a small access cover you could easyly check and lob in a handfull every now and again...

Maybe I'm over estimating how fast the condensate will errode the limestone and possibly the amount of liquid condenstate you get but it doesn't take much to produce a pint/hr. 1 1ml drip every 10s is

360ml/hr (0.63 pints).
Reply to
Dave Liquorice

I suspect that this was all written by somebody who had never actually done this, but know from their GCSE chemistry that limestone can be used to neutralise acid.

The idea of being able to replenish is a good idea, but I wonder if most people would bother.

The acid is not that strong anyway (about like tomato juice) and what the impact to the surrounding ground in comparison to dilution by rainfall would actually be.

I can't help thinking that this is more by way of something to address the imagined environmental concerns rather than the real ones.

Reply to
Andy Hall

Most people would leave it up to the "compulsary" annual maintenance inspection.

Thats quite strong in comparison to ordinary rain water and look what that does to limestone (given enough time...) B-)

I'm inclined to agree at 60cm depth it's well below the surface and the volume must be quite low if a 60cm length of 110mm pipe is suitable as a soakaway.

Anyone fancy putting a lump of limestone under their condensate drain to see what happens?

Reply to
Dave Liquorice

The plot thickens. I have continued this in a new thread as the theme has changed slightly. Please see new posting on the same day as this.

Blueyonder is not good for newsgroups so sorry if this does not appear at bottom of thread.

Reply to
Dave Smithz

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