Pipe size for Range cooker

[CJ10]

Hi there, looking for some advice as I have been given conflicting info. I have just bought a new range cooker (gas, 2 oven, separate grill, 5 burner 100cm) and my kitchen installer (B&Q) says that I need 22mm gas pipes from main supply as there are more than 4 burners. The pipes need replacing anyway as they are made of lead but the CORGI engineer we have doing it says that he isn't aware of this and that 22mm is an unnecessary extra cost and 15mm (?) will be fine. Emailed the manu but they just referred me to instructions book which gives me nothing! Are there any regs on this?
Thanks
CJ

 

[jj4091]

Do you have other gas appliances?

 

[CJ10]

A combi and a gas fire.

 

[jj4091]

I would have thought you would have needed 22mm from your meter & then branch off to each appliance in 15mm fo your cooker & boiler & 8-10 mm for your fire.

 

[CJ10]

Thanks for the reply, will ask the fitter to do that.