it may have course been dealt with before .....

I am looking to install central heating in a 5 bed semi - the kitchen
is very small and there is no external wall space to hang a combi -=
in fact there is very little space at all!

There are a couple of good reasons to put the combi in upstairs
bedroom - including easy access to outsdie wall and it would minimise
runs of pipe to showrr room, bathroom and kitchen

main question is how noisy are they ? this will be the main bedroom
are some less noisy than others ?

I assume 22 mm gas pipe (easiest run will be 35 feet from meter) most
of the way

I was thinking of two zones upstairs and down each fed by 22 mm pipe
6 rooms upstairs and 3 downstairs but more heat needed in downstairs
living areas of course Separate thermostats on each zone or do I just
rely on TRVs

any other comments ?