Condensing boiler (continued) - Told I cannot have as Cast iron Waste pipe - plot thickens!

[Dave Smithz]

(This continues on from an earlier posting but a new thread started because a lot more info is now available).

My Corgi engineer told me I cannot have a condensing boiler because I am on the second floor and I have a cast iron stack. I phoned Corgi and they clearly state the condensate waste SHOULD NOT go into metal waste pipes. If you phone Corgi technical help they will tell you the same. I am not in a position to build an alternative waste trap because I live in a flat.

However, my local building control would not authorise my exemption from a condensing boiler as I do not score enough points going through the exemption procedure (see link later below).

So this leaves me stuck. Do I break the law and go with what Corgi tell me and therefore install a non-condensing boiler meaning I'm breaking the law because I do not have exemption.

Or do I go by the book but install a Condensing boiler completely contrary to Corgi (And they say the British Standard advice - document 6798 p4 clause

423) and possibly avoid having to remove my boiler 3 or 5 years down the line because the shared stack (with other flats) is leaking due to corrosion?

This confused me so much I contacted the Office of the Deputy Prime Minister (ODPM) regarding their assessment form

.As a result they are actually reviewing the situation as apparently this has come up a few times.

However, I need a boiler ASAP / next week! Any advice on what I should do?

Thanks in advance

Dave

[Christian McArdle]

It sounds like the council assessment is wrong.

As you are not permitted to connect to a metal drain (and this is in the full procedure document), that particular installation option should be disregarded, AIUI.

Connection to external drains is a second choice anyway. Is there no way it can be connected to an internal drain?

Christian.

[Jerry]

In article , Dave Smithz writes

I just ignored 2 jags new rules and did my own thing. OK I don't have a pretty piece of paper to wave in the air saying that the new boiler conforms with current regs but so what? The only time anyone is likely to question it is if I sell the house and I can't see a sale falling through over that.

I don't have a problem with any rules or regs that improve safety. What I do have a problem with is when I am forced to pay for additional works where the cost to me personally is totally disproportionate to any environmental benefit. People get on a jet for their holidays and their personal portion of the aircraft's fuel burn would keep their central heating running for a year yet 2 jags ignores this and concentrates instead on making us pay dearly for minor domestic improvements in carbon emission that are trivial by comparison.

[john.stumbles]

My reading of BS6798, section:

4.2.3 Condensing Boilers COMMENTARY & RECOMMENDATIONS ON 4.2.3 ... c) The choice of condensate drainage pipe says that the condensate drainage pipe itself should be plastic (it names PVC, ABS etc) but says nothing about the material of the system it is connected into.

However I asked CORGI Technical Helpline and their interpretation is, as you have been told, that the condensate should not go into a system which is cast iron even downstream of the condensate drainage pipe itself.

As Christian says, the option for installaing the boiler with the condensate going into the soil stack has to be discounted in assessing the options and totting up the points for where a condensing boiler can be installed. If this results in a score which allows you to install a non-condensing boiler then you may do this.

It is not up to your local building control if the boiler is fitted by a CORGI installer as they can self-certify the installation under the building regs. I missed the earlier thread so I don't know if you're getting it done or DIYing, but getting your friendly local gas doggie to ticket it up for you might be one option.

[Aidan]

Interesting. Thanks for the feed-back.

Options are;

1) Gravity drain in a new plastic pipe. I'd have thought going into the CI stack below other wastes would dilute it sufficiently, but I haven't looked at what the BS says. 2) Neutralise it at source, see the Viessmann link on the previous post, then put the pH neutral condensate into the CI stack. 3) Get a condensate pump and pump it somewhere (through a loft, could freeze? ) where you can install a plastic drain, or where there already is one. 4) Get one of the other Corgis to fit a condenser; they will certify it and they don't see any problems. They're the approved & certified experts and who are we mere mortals to argue with them? Solve your condensate disposal problem at a later date.

That's it, I think. Any other possibilities?

[Dave Smithz]

Thanks for all the replies on this matter. I am still speaking to the Office of the Deputy Prime Minister on this matter. But I Think it will be a wait before any changes are introduced.

Some points to clear up .

• My boiler is being installed by a Corgi engineer. Of 3 quotes, only one said about the cast iron stack pipe, I then started to investigate -what a can of worms.

• I am on the top floor of a three story flat - no loft space available - no plastic drainers - no option to build any (well certainly not within my budget I do not fancy scaffolding the whole block and getting the paperwork for that etc.)

So really the communal cast iron waste pipe used by all flats but with me on top is the only option for it to go.

Maybe I just install a non-condensing and say what the hell. Really not sure what to do.

Dave

[Christian McArdle]

You need to speak to the BCO and explain that any considered locations involving using the cast-iron stack should be disregarded, as the procedure says that cast-iron is not suitable and the stack is not owned by you. After all, they wouldn't consider a location for the boiler in your neighbour's house, so they can't consider an option that involves you replacing someone else's pipework.

Christian.

[Dave Smithz]

Yes, I wish they would listen to me. When I asked them to put it in writing that I can install a condensing one, they wont do that either. I have now asked ODPM to confirm that I have at least tried to raise this issue.

Just cannot decide what to do. Only just moved into this flat so don't imagine I will be selling for at least 10 years (nut who knows) maybe I should go ahead and just install the non-condensing one.

I believe it will be cheaper and easier to maintain anyway. Right??

What is the worse that can happen to me if I just install the non-condensing??

Will the 79% efficiently compared to 91% actually make a big difference to my fuel bill?

Thanks

[Wingedcat]

Well with a non-condensing boiler, 79% of your gas bill is spent on heating your house and 21% on heating the outside world. This means that assuming an annual bill of =A3200 (roughly what I spend), =A3158 is used productively and the other =A342 goes out of the flue as waste heat.

If you fitted a condensing boiler, if I have got my sums right you would instead spend =A3158/91 * 100 which equates to =A3173.63 so you would save =A326.37 or about 13% a year.

If you are installing a boiler from scratch then fair play, but for me at any rate it's certainly not worth replacing my boiler until the current one packs up.

Luke

[Christian McArdle]

If you can't fit a condensing one, then you can't fit one. I would always fit one if it was remotely possible.

Christian.

[Andy]

Hear Hear!

Andy

[Doctor Drivel]

Well with a non-condensing boiler, 79% of your gas bill is spent on heating your house and 21% on heating the outside world. This means that assuming an annual bill of £200 (roughly what I spend), £158 is used productively and the other £42 goes out of the flue as waste heat.

If you fitted a condensing boiler, if I have got my sums right you would instead spend £158/91 * 100 which equates to £173.63 so you would save £26.37 or about 13% a year.

If you are installing a boiler from scratch then fair play, but for me at any rate it's certainly not worth replacing my boiler until the current one packs up.

[Ed Sirett]

Whilst the condensate might corrode a metal pipe it's going to take a very long time to do so and even longer when the condensate is being periodically swilled down by other waste water from your flat.

However if you are worried that someone will try to stick the possible demise (due to old age) of the CI stack on you then you will need to get the exemption sorted. That means finding someone who will certify that although there are not enough points for an exemption the absolute (cf inconvenient) lack of a drain for the condensate is clearly an absolute exemption.

As for the difference it might be 15% on/off the gas bill.

[john.stumbles]

Totally agree about the scandal of aircraft getting tax-free fuel etc, but that doesn't mean it's wrong to increase energy efficiency elsewhere, especially as a government could, if it had the gonads, tackle the former practically overnight whereas improving the energy efficiency of the housing stock takes decades.

Anyway what should happen with condensing boilers (and I think it is already starting) is that the prices should fall to much the same level as non-condensing boilers used to be before the change (or even become cheaper when they form the bulk of the market). Look at prices of combis compared to non-combis: the former contain far more work and materials but the prices are relatively low because they're big sellers. Condensing boilers contain far less extra compared to non-condis (a different heat exchanger and some bits of plastic for the condensate drain) so there's no reason their prices can't drop to non-condi levels as sales volumes increase and manufacturers competing on price.

Oh, and I don't fly to my holidays :-)

[Doctor Drivel]

On the TV tonight. A nuclear power station will take 10 years to get into service. Getting homes energy usage down by 50% is easy with existing technology. In 10 years about 5 million homes will be built, then efficiency in appliances and improving existing housing stock too.

Anything that saves energy is worth it., inc condensing boilers.

[John Rumm]

If it were me, then I would go with an condensor drained into the CI stack. Any corrosian of something like that will take a long time, and you can always play dumb on the grounds that you were guided by your CORGI. Make sure the connection to the stack is either below the others, or better still mixed with them, and it will further reduce the possibility of problems.

After all it is not like the prohibit you flushing tomato sauce or vinegar down the sink!

[Fred]

Tax of heating fuel and electricity in the UK is the lowest in Europe. If Labour and Tory wets hadn't have voted against full VAT on heating fuel etc, then I might have agreed with you. Airlines are taxed on landing and on passengers.

If for airlines the taxes represented fuel used then this would be a significant step forward.

[Fred]

I would suggest you need to talk to your councillor and highlight this problem particularly how BCO are going against guidelines CORGI adhere to.

In practice though I'd go for a condensing one and if later there is an issue let CORGI deal with it. If one of their installers incorrectly plumbed the condensate into a CI system then it's the installer's or CORGI's problem and indeed why they carry insurance if there's any liability on your part if the pipe perforates.

[Dave Smithz]

Thanks guys.

For the record, here is Vaillaints response:

" If your requirement is for connection to a house soil and vent stack, British Standard 6798:2000 gives this as a preferred method.

1) Internal termination to internal stack

The condensate drainage pipe should have a minimum diameter of 22mm with no length restriction. It should incorporate a trap with a 75mm condensate seal and be connected to the stack at a point at least 450mm above the invert of the stack.

The condensate is acidic but not acid, in the normal course of events liquids of an equal or great acidity are routinely poured down a sink or toilet. The level is about the level of fruit juice or cola type drinks and while not that palatable would not be considered hazardous if drunk. The maximum condensate is only 2.2l/h but in normal practice will be much less due to modulation of heat output. Therefore the connection between the boiler outlet and stack pipe should be a form of plastic pipe not copper pipe, once at the stack pipe and therefore into part of the normal drainage system no restriction is put on the stack pipe material. So the installer is half right in that the connection from the boiler should be in some form of plastic but there is no such restriction in the stack pipe material. I am surprised CORGI expressed any view on this matter as they normally refer these matters to the manufacturer concerned as this is not directly to do with gas safety.

I trust this is of some help.

"

I think I will go for the condisating boiler.

Thanks

[john.stumbles]

...

Thanks for that.

The bloke I spoke to at the CORGI Technical Help line seemed to be recommending that I - as an installer - should not connect a condensate drain into a CI stack from an arse-covering point of view: "how do you know the condensate won't corrode the soil stack?". In other words if the stack corrodes through (for whatever reason) you don't want someone pointing the finger at your installation and blaming you (and possibly suing you for the damage) for it.