installing combi central heating system - diy

[Mike]

Hi We've recently bought our first house (which is more of a project! - lots of work needed) and finances mean must DIY as much as possible. We currently have an old back boiler system with hot and cold water (plastic) tanks in a bedroom cupboard which we are thinking of replacing (along with a hideous 70's gas fire attached to the back boiler) I'm thinking of having a crack at some of this myself. Obviously, being a plumbing novice, I will have a lot of research to do before starting but any help on these basic questions would be much appreciated:

1) Is this a realistic project for a DIYer or am I biting off more than I can chew!

2) From a 'developers' point of view (as we hope to trade up quite quickly) is it even worth replacing the system. The existing system does work and the house is only a modest 2 bed terrace worth about 85k when finished. Is the work likely to add more value than it costs?

3) I need to clarify what I can do myself by law. I was thinking I would get a CORGI pro in to do all the gas fitting. Am I right in thinking I'm ok to run any new non-gas pipe work and install / replace new radiators my self plus physically fitting the boiler without making the gas connections?

4) I have had a couple of people in already to quote but they can't seem to agree on what needs doing - in particular if existing pipe work to radiators is up to the job or needs replacing. Its standard

15mm copper and looks ok to my untrained eye (apart from a couple of leeks round radiator valves which I intend to replace anyway) People trying to make work for themselves? Could do with some guidance on this.

5) Is there anything I can do myself regarding replacing the old gas fire and removing the back boiler to keep costs down?

6) New gas pipe work will be required as any new boiler will be in a different location and we want to install a gas cooker. Again, any sort of preparation work I can do here to keep costs down?

7) We currently have an electric shower which has seen better days. Any thoughts on if it is best to replace this like for like or incorporate the new shower so that the new boiler supplies the hot water to it?

8) What order to do things in? Better to have pro in first and then do new radiators, pipe work etc or best to do all the diy stuff first and then get pro in to finish off and get gas connections done?

9) Better to buy boiler myself or will Corgi guy get it cheaper?

10) Any website or book recommendations to help with this project?

All of the above assumes the new system will be a fairly basic Combi system with water tanks being removed to make room for the new boiler. I know there are a lot of opinions out there as to the pros and cons to this type of system, but as far as I can tell it's the only real option for someone on a very (very!) tight budget ..... unless someone knows different.

Thanks to anyone who took the time to plough through that lot! I'm sure its pretty boring old ground to the more experienced readers but I don't want to be caught out by new regs reading old threads. Any help will be Massively appreciated!

[Andrew Gabriel]

It's not worth doing. No one will pay extra for a new boiler. It would only be worth doing if the old system didn't work (and in most cases, people don't even seem to notice if a heating system works or not) or you were planning on staying.

People will probably only notice if it looks bad. Can it be cleaned up, with a new hose and showerhead? That might be all it needs to work better in any case. Otherwise a like-for-like swap.

[John Rumm]

It is certainly doable if you don't mind doing some reading and practising some of the basic skills. You would probably need to budget a few hundred for tools as well if you are starting from scratch.

Probably - it won't detract from the value, and it will remove one objection that potential buyers may have. If you think the gas fire etc is hideous, then there is a fair chance they might as well. Seeing a new(ish) system in place gives some confidence (possibly misplaced) that there one less thing to worry about for a few years.

You can in law do all of it yourself including the gas fitting if you are "competent" (there is no definition in the law as to what this means). You would have plenty to read up on as well as needing to be confident in your ability to reliably make pipe joints every time. The requirement for CORGI registration only kicks in when trading as a gas fitter.

Much will depend on the the quantity of sludge in the system. However much of this can be flushed yourself - especially if you convert it to a sealed system.

Even if you were not confident with the gas side, you could have that professionally cut off and capped and then do all the decommissioning yourself. You would obviously need to think through the logistics of keeping enough heating and hot water system working.

As a minimum you could agree a pipe run with your fitter and then make sure all the holes are drilled etc to ease his job. You could go a stage further and run the pipework, leaving it disconnected at either end.

Much of this presupposes that you can find a CORGI that is prepared to work like this. Give it is currently a sellers market you may find that difficult, since this sort of thing puts the pro in a slightly difficult position regarding product liability etc.

Even the smallest combi will give a far better shower than the best electric. Having said that, it would be wise to keep the electric until after the boiler change is complete. That way you can rip out the ho water system and you still have a way of washing.

Both probably - you need to agree what you are going to do in advance with your fitter.

The latter if it is not you fitting it. Again product liability, and the ability for the fitter to profit from the sale of the boiler. Chances are he will be able to get it for less than you can, but would then sell it on at a price comparable to what you could achieve. So to you it makes little difference except you have one clearly identifiable person to blame if it goes wrong.

Loads... But here is a good starting point - there are links in there to find out everything else you need like Ed's boiler choice FAQ or gas fitting one.

All of the above assumes the new system will be a fairly basic Combi

Read the above to get a feel for the options and complexity.

Tis what we have the FAQs for etc. so help yourself.

[PM]

Make sure you can find one willing to do this first. I was turned down by several companies who wanted the whole job, or nothing.

Plumbing heating and gas installations (Treloar) Plumbing mechanical services, books 1 & 2 (Blower)

All on Amazon

[PM]

In addition, the work is notifiable to your local BCO (may be chargeable - mine wanted £240) and they may want a CORGI reg'd person to provide the certification at the end.

[abaker]

I was in an almost identical position several years ago. The only difference is we had no heating system in the first place. I looked into doing it all myself, but in the end decided to do just the wet work and employ a CORGI guy to install the boiler including all gas pipes. This I think worked really well and is the approach I wold recommend.

Learning to plumb is an invaluable skill and will save you thousands over the years - I know people as young as I employing others to install washing machines! Whilst getting the plumbing wrong, the worst that will happen is a leak which can be dealt with easily. The first few soldered joints certainly weren't perfect. Getting gas wrong however is a bigger risk and one I saw no reason to take. By doing the wet work yourself you will be saving on the cost of the time-consuming labour of that installation - more often that not, the gas work is quicker and easier.

Also don't bother with courses. Do lots of research online, get the tools and equipment and have a go. You may end up re-doing much of the early work once you become competent but the pleasure of knowing you did it yourself is worth it!

Good luck and let us know how you get on.

[Dave Plowman (News)]

Leave the gas to last? You should certainly have learnt how to solder after doing all the wet stuff in the average system.