Problem with condensing boilers and cast iron stack pipes.

sausage84

Hi,

My boiler (an old Baxi thing from the 60s or 70s) broke down in October and I have been waiting to save up the money to get it replaced. Yes, it has been cold!!!!

I am the leaseholder of an ex local authority flat in a 1930s council block, top floor of five floors.

The problem is that my gas man is saying he can only legally fit a condensing boiler, but there is a chance the condensate (which is acidic) will corrode the cast iron stack in the block.

Also, all of the pipes outside, including guttering, are iron, not plastic.

Essentially, the only boiler he can legally fit (as it is now against regs to fit non-condensing boilers) could corrode the outlet stack for mine and eighteen other flats. Not sure the council would be best pleased about that. We cant fit a non-condensing one as the council must be notified of the boiler work done.

Any thoughts from people with experience of this? (I found a slightly older post on this, but it didnt give too much help.)

Thanks,

Sausage

gas4you

The general thoughts now, is that the cast iron stack will be ok due to the amount of other fluids going through it to dilute the condensate.

However, your gas man should also know about the 'condensafe' neutraliser, that removes the acidity from the condensate, therefore allowing it to drain away safely in any material.

vaio

And, isn’t there a get out in the regs if fitting a condenser is impossible (or maybe even impractical)?

gas4you

Yes there is but I have never come across a situation where a condensing boiler cannot be fitted, although there must be somewhere.

The thing is, that if you obtain an exemption certificate, then the job is inspected and the 'inspector' who probably knows nothing about boiler installation says you could have had a condensing boiler, the installer then gets fined £5000 and £50 per day until it is replaced.

Hence why I would rather walk away from an exemption job.

sausage84

gas4you wrote: »

The general thoughts now, is that the cast iron stack will be ok due to the amount of other fluids going through it to dilute the condensate.

However, your gas man should also know about the 'condensafe' neutraliser, that removes the acidity from the condensate, therefore allowing it to drain away safely in any material.

Cheers. Hopefully it will be ok, but I could do without the council knocking on my door in two years time if it isnt. The neutraliser was mentioned in a previous conversation so I'll see what the deal is. Is it effective?

vaio wrote: »

And, isn’t there a get out in the regs if fitting a condenser is impossible (or maybe even impractical)?

I'd like to think that, but you know what they say about the law!!

I'm surprised that this isn't a common thing with proper guidelines. There must be loads of condensing boilers flowing into cast iron stacks.

gas4you

The condensafe is effective, but needs replacing each year at the annual boiler service, therefore adding to your annual running costs.