Sorry mate I meant Heat only Boiler. This way the hot water is stored in a tank and there is flutaution in water temperature when you run a shower and run a cycle on the washing machine.
I am not a plumber mate. What I do know is that our house is a 6 bedder with 2 en suites.
What we do is a Heat only boiler in the downstairs utility room. There is a pump upstairs in the Airing cupboard which pumps the water from downstairs into the hot water tank.
We then have a 2 bar pump under the bathtub. This pumps hot water from the tank in the airing cupboard and cold water from the tank in the loft into our high flow shower.
We were attracted to fitting a combi boiler initially but were advised against it by a few plumbers who said basically we had to have a gravity fed set up.
Thats all i know.
What I am wondering is, if you have a pressure issue which I am sure would be easy ( hope so) to fix. I am wondering if you are planning on setting up the second shower in the loft? In which case are you sure your combi will be able to cope? I am not sure it will.
using deductive logic ( again i am no plumber). You wont be able to put a pump from the mains into the combi boiler. ASFAIK pump makers prohibit fitting shower pumps to the mains. Usually you can only fit these after the boiler or after a tank?
Secondly fitting a pump in the loft ( if that is what you are going to do) will only magnify the issue of flowrate.
1. if by any chance you can buy a pump to the boiler. It can only heat water at a certain rate.
This would be the issue people have with those little electric showers. They heat the water and push it out the head but whilst the flow is ok its never super powerful is it?
2. Even if you put a pump in the loft for the shower, you will be pulling water up faster than it can be heated?
Or am I missing something here?