Central heating.

Eventually we have decided that our RayBurn has not got enough output to heat the house so we are investing in a new system.

We have a maindoor flat in Scotland on two levels that has 2 reception rooms, four bedrooms, two bathrooms (one with a shower pump direct from hot water tank), Kitchen and a utility room.

We need a hot water tank for the shower pump but quite like the idea of a combi boiler. Is it possible to have three circuits on the combi boiler:

For the Heating
for the instant hot water
as a small circuit that only heats the water tank

If I could do this then I would have the best of all worlds - hot water to the bathrooms when I need it from the combi lots of heat from the new boiler a time on the combi to heat the hot water tank on a timer

If this is possible then how can it be achieved ?

If none of this is possible then any suggestion would be appreciated!

Cheers l.c

Yes you can.

You plumb it up in the same way as a system boiler. The only difference is that the combi might expect volt free contacts thermostat rather than a live "call for heat" function. This is easily implemented by using a Honeywell S Plan system. The microswitches on the 2 port valves are connected directly in parallel across the combi thermostat terminals.

A conventional programmer, (preferably programmable) room stat and cylinder stat are used to control the 2 port valves. You may or may not need an automatic bypass valve; this will depend on the boiler selected. TRVs should be installed on all radiators that are not in the same room as the room stat. In that room, the radiators should have lockshields both ends to prevent the user from turning them off.

Christian.