diy Combi boiler install

[dave]

I'm thinking (!) about installing a combi boiler which will be used to provide hot water and supply just 2 radiators. The other rooms have gas or electric heaters which are staying as is. A couple of questions if I may:

- If I do the installation myself, will I be able to get a Corgi reg person to commission the boiler or is that likely to be a problem? (As he hadn't fdoine the actual boiler installation)

- I'll need to run a new gas feed from the meter to the boiler. I cannot do the actual connection to the meter of course - so, again, will a Corgi reg person do that or do I have to contact the Gas supply company about it? Is that likely to be a problems as they haven't run the pipe?

This is a very new project and I have quite a bit of learning to do (I'm not too bad at DIY though - given some advice on ways and means :-) )

For example, there is an existing 1/2 gas feed from the meter to a gas cooker situated on 1.5 m away from the site of the proposed new combi boiler (wall mounted). Would it be best (required) to run a completely new feed pipe to the boiler? Or would it be better/allowed, to run a sufficiently large diam pipe to the cooker and then continue it to the boiler?

thanks vm.

[John Rumm]

There is nothing in theory to stop that happening, however it would be wise to pre agree with said Gas Safe bod (CORGI is so last year ;-) that this is what you are going to do. In this day and age its not uncommon to find the limited number of fitters can cherry pick the most profitable jobs and skip the less rewarding ones.

The gas fitter[1] can run a new pipe from the meter. Its only connections on the supply side of the meter that they would not be supposed to touch.

[1] as has been discussed here often before, you can do your own gas work if you are competent, and competence does not require gas safe membership.

Either are acceptable. If using a combined pipe it would need to be sized so as to cope with the full demands of both appliances. (the Copper Development Association publish tables of pressure drop Vs pipe length for gas, so you can compute the required pipe size etc)

[Lobster]

Plus you would in effect be asking said fitter to take full responsibility for the quality of your work, and assuming he doesn't know you from Adam he's understandably likely to be reluctant to do so.

For example, consider: it wouldn't be impossible for a (hidden) solder joint to be assembled using flux; you forget to actually heat it to melt the solder, but notwithstanding that the presence of the flux could mean the joint is actually gas tight when tested... but not some weeks later once the flux has dried out. Why would a fitter want to take on that responsibility, especially when he can do more lucrative work elsewhere, without the risk?

Not saying it will be impossible to find someone, but just make sure you definitely get him lined up before you fit the boiler or you might find yourself with a full installation that's impossible to get certified!

David

[dave]

On Wed, 07 Oct 2009 07:49:34 +0100, Lobster wrote: [...] Points taken. All the pipework here would be visible for checking so that might make it easier I suppose (no underfloor/in-wall stuff).

[John Rumm]

If you can agree to split the work, it might be that you do all the wet plumbing, but leave the gas work and the final commissioning to him. You will also want to think about how you plan to clean and flush the system prior to the new boiler being commissioned.

[YAPH]

What about the inside of the gas pipe? How can I tell that you've used the correct sort of flux for gas pipework, and not got excess on the inside of the fittings, which could corrode through them in due course? So why should I risk the weeks of my time and hundreds of pounds of my money it took getting and maintaining my gas qualifications by signing off your work for ... how much did you say you were paying me?!

Talk to your installer *before* starting!

[js.b1]

I personally would not suggest anyone but a very experienced DIYer consider soldering gas pipe. Yes you may do it correctly re heat activated flux, correct solder, wiping joints, sleeving pipe in gas ok- to-carry where it goes through walls/cavity etc, gas manometer tests, gas valve with pressure-test-fitting on the end - but the fitter may not agree. Talk to them first.

An alternative, particularly if the gas pipe is run outside, is to use TracPipe.

- TracPipe is a coil of convoluted stainless with factory applied yellow ochre coating

- No solder issues, very fast fitment, impact & "movement" tolerant

- Significant labour saving over cut copper installation

You still need to 1) not overflex re limited number 2) keep to min & ideal bend radius 3) use proper wall plugs, locking clips and 4) correct termination re split-ring assembly 5) absolutely must use the correct TracPipe yellow silicone tape to cover any exposed ends.

If the fitter refuses to use TracPipe and wants lots-of-joint copper it is re labour rate and you may want to get a second quote (reason is the stuff BG did for me in 1996 is so bad Transco had to redo the soldering then gave up at the 8mm pipe into 15mm elbow filled-in-with- solder. Every joint leaked on the back as not a continuous bead. TracPipe whilst not cheap avoids a lot of these problems and frankly is better (proven UK USA Japan and elsewhere now).

To be blunt, you have little chance of doing a *competent* gas fitting job on pretty much anything without a copy of Tolley's &/or Viper manual by you, plus proven skills. Many fitters only have multiple choice it seems, soldering has gone diabolical - no wonder they ban lead re complexity of proper lead wiped joints (NCS if ends have brass/ copper fittings).

Water-side, well that's on your head - gas-side I would suggest DIY only do limited scale or TracPipe if only for "well there's only 2 friggin joists so if the pressure fails the manometer test there are only 2 places to check!". Lean on water, not gas - unless you have the full manuals.

Ensure the boiler end has a pressure-test fitting, even now a lot of gas taps seem to lack an integral one so you get quite messy installs. Test pipe is so you can verify gas pressure at the appliance and gas tap is so you can verify the pipework has no leaks because appliances are isolated. Oddly enough BG & others avoid fitting both even now - because that permits a small leak "if appliances no isolated" and if no smell of gas they walk.

[Heliotrope Smith]

I'll have a firkin or two of what this one is on!

[js.b1]

Apologies, atrocious post needed severe editing & typo fixes.

In short.

1 - The problem with DIY gas work is not knowing what you do not know

- and why it is important.

2 - Without proper manuals you can only guess good practice. Good practice is more than "A joints to B so that is ok".

3 - Soldering copper gas piping has a lot of safety aspects. Calculations re pressure drop, correct preparation & making of every single joint, pressure testing, proper purge procedure. Adopted pipework is invariably "quicker to replace" and a 3rd party will probably want the whole lot scrapped if they find anything wrong as not taking responsibility for critical live gaswork and will be hyper critical. It is bad enough getting one Corgi to accept another Corgi's choice of thro-wall-sleeve "I can not identify what plastic it is so it is coming out" because of the ambiguity of "suitable for carrying gas". GasSafe replace Corgi now obviously, an interesting named re implied competency :-) GasCapita might have been more fun.

So I would suggest DIY choose TracPipe rather than copper piping, externally run can be quite convenient too.

Water side, that is fine for DIY - you can only drown yourself (although blondes usually forget to put the sink plug in).

[John Rumm]

Yup, quite agree. However, if you know enough to do all those things then you probably don't have need of the fitter in the first place.

Read about it enough, but I don't think I have seen it used yet. Perhaps its a case of old habits taking a long time to die.

There is a distinction between being a competent fitter in the general sense, and being able to do one specific gas fitting job competently. The latter is far more achievable for someone without formal training, as long as they are prepared to do the required research. Many readers of this group for example, would know how to come by copies of the relevant British standards docs for gas pipework etc, and would be well aware of how to joint, test, purge etc given the number of times it has been discussed, and described by trained fitters etc. (they would probably even be aware of the requirements to maintain electrical continuity of pipes when carrying out modifications etc - something I bet few of us have ever witnessed a professional fitter do!)

Tolley's for example contains a vast amount of information that goes way beyond just gas fitting. There are whole chapters there on building construction, nails, screws, lifting floors, notching joists, types of water storage system and all the associated controls that go with plumbing and heating in general. All of which is very relevant practical information for someone wanting to carry out the trade of a fitter, but much of which a good DIYer would already be aware of anyway.

Not just on pipes. You want to see some modern electronics graduates attempting PCB population or repair!

I would bet more people have been injured by dodgy water plumbing than by DIY gas though. I don't ever recall reading about any incident relating to DIY gas fitting[1], but have read about a few that came about from poor plumbing practice. (the cases of hot water cylinders boiling and venting into plastic header tanks, that then collapse and dump 40 gallons of scaling water through a ceiling onto someone sleeping below, spring to mind).

[1] I am talking about original installation work here mainly, and excluding the cases of ill informed numpties attempting to mend or service their boiler and creating CO hazards.

Another area where someone working on their own installation is going to be far less likely to accept something that meets the letter of the rule if the the spirit than a third party.

[Rod]

It might have been more fun. (Define fun. :-) ) But GasSafe (as a brand/TM) is not owned by Capita. They are contracted to run the operation but even if they lose the contract, the scheme will not have to change name.

The current situation where money and effort is being used to heighten awareness of the change of branding would surely have been better used encouraging real safety or reducing costs?

[Dave Plowman (News)]

Think that possibility is much exaggerated. You would need a huge amount of active flux to eat through a pipe - the chemical reaction gets used up. Rather like not wiping it off the outside - all that happens is a small coating of green.

[Andrew Gabriel]

I watched as new boilers were fitted in loads of council flats I walk past. Apart from the fact that they now have copper pipe running all around the outside of the buildings (which actually looked quite respectable until that point), there's not a single sleave to be seen on any of the pipes where they go through the wall, although they have actually gone to the trouble to mortar them all in afterwards. :-(

Of course, mine are all sleaved, but then I did those myself, so I knew they would be done correctly.

[js.b1]

I have memories of them spending their time making electrolytic projectiles :-) They did some useful work of course, according to their girlfriend!

Yes, someone doing their own work can better control the standard... they have to live with it.

I suspect even now a fair quantity of gas & electrical kitchen work "continues" after the Corgi or Spark has left. Most of the faults at my mother's were actually kitchen fitters moving cables around to avoid cupboard screws, added pipes, then patching on extra cable (CPC twist, choc-bloc L&N) which remain dangling(*).

The usual case of doing several things badly, one thing... erm... well.

(*) Will be fixed shortly by 2.5mm BS8436 off existing RCBO - unlikely I can keep in zone for all its run re pipework.

[js.b1]

Copper pipe looks ok in very few situations. I believe USA allows TracPipe to be run underground (say to a garage or alongside a house), whereas the UK doesn't permit that sort of thing AFAIK. Probably because they would blow up a few rats & sewer network in the process.

I've seen the same lack of sleeving, and that is through cinder block & coal-dust mortar - both of which nastier than plain cement.

Sadly we are good at creating closed shops, but not the skills within them - perhaps implicitly.

[Dave Plowman (News)]

'Closed shop' generally refers to unions. And are illegal. But not the so called 'professional body' ones.

When I belonged to a union which operated a closed shop it took great care when issuing a 'ticket' for a particular position with the exception of trainee. So it would be nigh on impossible for an incompetent to get that ticket. When you allow a commercial organisation to run this sort of thing more members mean more profit. So a dichotomy.

[F]

I did this myself a few years ago and had quite a few phone calls to make before I could get a Corgi reg to sign commission it. Even then, he made sure he signed up to the very minimum he could 'Never sign for more than you've done' was the phrase.

Get your Corgi (AKA Gas Safe) lined up early on...

[js.b1]

That is what I find odd.

You would expect an off the shelf yellow tube "marked gas every inch"

- BES do some tube, but I think that is plain black plastic pipe which anyone can quibble over.

Only yellow plastic round here is about 12in diameter... a bit big...

[YAPH]

You are probably, almost certainly correct. But maybe you and I are wrong and there is some mechanism - maybe akin to bronze disease - by which it could happen. Then if I had signed off that work as my own I'd get the book thrown at me for bad workmanship, maybe even manslaughter, and all for what - a few quid? Why take the risk?

[YAPH]

When I made the mistake of buying some once it turned out to be roughly sawn-up lengths of 32mm plastic waste pipe!

Even if suitable tube were marked every millimetre it wouldn't help since, by the time it comes for inspection, it's buried in the wall. It would have to have the marking embedded in it continuously so that it's visible on the cut ends, like seaside rock! Or maybe we'll start having to fix an ID plate beside the tube, as they have to do for chimneys nowadays. That's be popular with the punters!