Help and advice please

Hi guys.

Our last two house both had hot air heating and hot water tanks etc.. both of these we removed and i fitted combi's and rads (getting a pro into commision them)

Our new house has a more traditional vented system. I've spend awhile sat in the airing cupboard and just about know were all the pipes go! Everything seems to work well although some of the radiators are extremely rusty and the showers have very little pressure. I've got to move the plumbing in the bathroom (another project!) anyway so i thought i'd flush/drain the sysytem and fit a pump to improve the shower supply.

-So any advice on draining the system, will it be harder as we have 17 radiators? Is it possible to keep the pump running while the header fills to help flush the water out or is too risky on the water pump?
-Any advice on shower pump purchases and fitting, i've got about £300 max and it will need to run two showers although not at the same time?
-The boiler is a Baxi the only no's I can find are wm 60/3rs it was fitted when the house was built during the 80's. If one day we decided to fit a combi would it be ok on a very large house and running showers etc... or are we best to stick with out current set up boiler hot water tank?

Any advice to any question would be much appreciated!

Cheers Zeb.

I wouldnt recommend keeping the pump running whilst draining the system. Turn off supply to expansion tank and drain via lowest drain point. If water. is very black then you may need a power flush to clean the system,.
As for the showers yes a pump wouls be the best option, if being that your showers are gravity fed at the moment via your header tank. Prices vary so shop around.
If you have a high demand for Hot water then i would suggest you stick to stored hot water. Combi,s are not really up to large demands.

although called a pump it is a circulator .. so it doesn`t help leaving it on .. it just knackers it up .. runing dry. dont fit a combi on large premises.. unless a floor stander with the 5 litre back up vesel. (these work great )..

as to the cleansing of the system .. power flush if possible otherwise add a restorer and leave in the system for a week or so . 2 may be req. then add an inhibitor.

Thanks guys.

With regards to the additional pump i'm going to add. Does it make any difference were it goes, in the bathroom? next to the hot water tank? Unfortunately the stored cold water supply for the bathrooms goes know were near the hot water tank but I can always plumb across if needed.

cheers