Boiler upgrade problem

[GordonB007]

My problem is that i am wanting to replace my conventional boiler with a combi, the real advantage to me was this would facilitate the removal of the hot/cold tanks so i could utilise the space.

I had a British Gas engineer round last night would indicated the scope of the work was;
- New 22mm gas pipe, installed externally round the side of the house.
- TRV's for the rads
- New boiler
- Removal of tanks.

For this i was quoted £4.5k.
My first question is, is this reasonable? I'm phoning a couple of local plumbers to give me alternate quotes.

My other question is regarding the new gas pipe. I don't particuarly like the idea of the pipe going round the outside of the house, but the alternative is to dig up the floor of the whole ground floor (concrete, gas meter at front of the house, boiler at the rear)... Not much of an alternative huh? Especially when the house is recently decorated.

I've read on various topics on this (and other) forums, about people wanting to put combi's on 15mm gas pipes, and i understand this is a definate no-go area.
Is this also the case for conventional boilers? I've been unable to find any boilers on the web with a 15mm inlet, they have all been 22mm which means no-joy on the building regs. Are there any new boilers that take a 15mm gas input???

I feel at a bit of a loss, and would appreciate some advice. Thank you in advance.

 

[AlanE]

Size of gas pipe relates only to how powerful the boiler is and how far away from meter.

Not building regs but gas safety regs. Too small a pipe and pressure drop becomes larger than permitted. No combi will work on 15mm cas supply and only lowest powered normal boilers will if very close to the meter.

Some boilers have a 15mm inlet but that must be increased close to the boiler. It doesn't mean that a 15mm supply is sufficient.

 

[tryitandsee]

Is 4.5k worth spending to create the extra space you require. Perhaps you could move the tanks in the loft nearer the eaves, using a coffin tank type configuration, much cheaper solution

 

[simond]

All you can do is get alternative views from other heating specialists who have seen the property.

So much depends on what the options are on site.