OMG - Not been on this site for a couple of years - This 1 thread has had me in stitches; I've not seen 1 bit of advice justified and read a total load of garbage from both RGIs and a certain someone from London called Mike - All of which has been highly entertaining I must say.
I'm one of those evil RGIs that doesn't give away trade secrets; but I must just add the simple point...
This is 2012 - We've learn't a lot about Gas in the past 30 years. Forget what you "think" you know; these days you need to know...
Any DIYer can undertake gas work so long as they are "competant" to do so; they do not need to take a test, be accredited or registered with the HSE under the Gas Safe scheme. However; they must be competant; the information requested is quite plain to see in any of the gas engineer publications such as Tolley's and Vipers... To be "competant"; we'd expect that one of these manuals was to hand as these are the "regs condensed" as the job involves the following stages:
a) Assess the desired appliances, is it a 2 ring, 4 ring, 5 ring burner; has it got a wok burner in the middle and what is it's NET gas input value (Irregardless of whether or not the appliance has been purchased, the home owner will need to know so that the pipework can be sized accordingly).
b) What is the desired route and where will the connection be into the original carcass? Is this going to simply tee into an existing supply and will that existing supply need to be upgraded to safely supply the new appliance?
c) What material is being layed on the floor; we're suggesting a screed as underfloor is going in; as such, we need to wrap and protect the pipework; if it's a complex run, we go under the underfloor, add volume to counteract the effect of elbows, bends and fittings.
d) The homeowner stated that it is "roughly straight", well copper is straight - How are the bends being formuated; or is a flexible gas pipe being utilised like TRAK... In which case; this will effect how the pipework is protected from the corrosive effects of the screed.
e) Pressure testing must be carried out - Any gas engineer that leaves a gas leak has NOT done their job properly - In a standard domestic situation it takes 4 minutes - No more; no less; no excuses.
When a homeowner asking for advice can give some solid evidence that they have done their ground work and are competant; then fine, we all need to bang heads and ask for advice - But Mike; you have some balls... Congrats; you have a great and varied knowledge, but you are obviously not a specialist and should refrain from giving wrong advice - I feel sorry for the person that buys your house from you; it's obvious that they are taking on a massive project; with a 30 year old, DIY fitted boiler which may be great in your eyes, will be a costly, inefficient beast to run and replace.
Hats off to the RGIs for standing their ground; but come on, show some reasoning and not just "Get an RGI"... Explain why and justify your cash.