I've repeated this post in the Central Heating forum, so I would be grateful if anyone wishing to reply would do so there.
Could someone please advise if adopting the following approach would achieve compliance with current legislation whilst maximising the DIY content. Only steps 3, 10, 12 and maybe 11 done by professionals – I fitted the original vented system along these lines.
1. Size select and purchase combi boiler after research
2. Isolate boiler and drain system.
3. Engage Gas Safe Reg to disconnect gas and cap off away from work area
4. Remove old boiler, tanks and hot water cylinder along with interconnecting pipework (weigh-in at scrap metal dealer)
5. Replace all valves in central heating and hot water feed lines with valves more suitable for mains pressure – existing valves could be up to 30 years old
6. Replace any original radiators and suspect radiator valves - most have already been renewed over the last few years.
7. Mount new combi boiler on wall
8. Prepare flue route and fit loosely
9. Connect new flow & return, hot water supply pipework and cold feed to boiler via isolate valves
10. Power flush – don’t know how/who does this yet, so help appreciated.
11. Connect programmer etc and elec supply – yes I know I should use an electrician but I did rewire the house 15 years ago
12. Call in Gas Safe Reg to fix and seal flue, connect gas and commission boiler and system, and sign off work if satisfied.
I am not qualified to comment on compliance but I did virtually the same some years ago but all new as no existing central heating.
I even did all the gas pipework except for making the solder joints, that was left to a Corgi guy.
It certainly saved a lot of money as I got a better system for the same money quoted for full installation. All pipework insulated, holes through joist centres etc etc. even built my own controller for twin pumped system priority. costs peanuts to run and only had three faults in 10 years. Biggest problem being the boiler manufacturer not being able to listen !
I would however suggest you find a registered plumber to list his checking requirements and to quote for inspection, connection, commissioning and " signing off " :D
There's nothing stopping you doing all the plumbing work, radiators valves and pipework, and cold flush the system before the boiler is fitted.
I would leave the boiler installation and flue to an RGI - and bear in mind that if when the boiler is fitted and the system is filled if there's a leak, problems with radiators problems with pipework - crap in system etc etc who will put this right ?
The RGI will probably also want to flush the system and add inhibitor so that your warranty is valid.
Thanks guys for your replies. I certainly reckon there is plenty that can be done without getting involved with RGI stuff. All I have to do now is find a RGI who will play ball and is happy to check my work do the gas associated stuff, power flush the system, commission and sign it off. Something to do in the spring when the scrappage scheme is in full swing. On the boiler selection front I'm currently thinking st/steel HE, so looking at the Which Mag recommendations it's either a Vaillant or a Baxi, as they seem to come tops for functionality, efficiency and reliability.
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