Vaillant ecotec plus 831 combi boiler pipe size help

Hi all,

just a quickie (hopefully).......can anyone plse confirm what size pipe should run to the boiler for the gas and water?
I think the actuall connections at the boiller are 15mm, the connection from the main water supply will run from a 22mm pipe which is within 2metres of the boiler anyway, should a 22mm be run from this up to the boiler where if will change to 15mm or is it ok to run a 15mm pipe straight of the main water pipe to the boiler?

Again with the gas supply to the boiler is it ok to run a straight 15mm supply from the main gas supply to the boiler, the boiler is very close to the gas supply anyway so not sure if the a 15mm or 22mm pipe will make much difference?

Any help is appreciated!

Cheers
John

PS
If it makes any difference its a 3 bed with a shower and no bath.

15 is ok for the water.
Not enough info re the gas, but if you can't work it out you shouldn't be touching gas.

Thanks mate.......im not doing it (no way!), I just like to know how things are meant to work and be sure the work is being carried out correctly.
Gas wise the boiler will be running the usual sink in the batroom and kitchen as well as the shower and 7 radiators, the gas supply will literally be within 1 metre of the boiler, does this help at all?

Cheers
John

Ok, just read a bit more about this and I should have known it would require a more indepth calculation for the gas i'll just let the fitter work it out and stop worrying........thanks!