In an earlier contribution to this discussion,
wrote:

Another question:

After being recommended to us a S plan system with 2 port valves, I'm
thinking why 2 valves and why not one 3 port valve?

What happens if you were to use 1 2 port valve?

Christmas Greetings to all.


An S-Plan system has 2 or more 2-port valves - one for each heating or HW
zone, and provides independent control over the zones - only running the
boiler and pump when one or more zone is demanding heat.

If you only have one 2-port valve, you cannot control your CH and HW
separately - so you might as well have no valves at all!

A 3-port valve is used by Y-Plan systems - and also enables you to have CH
or HW, or both together. It's main disadvantage is that the valve actuator
plays a more strategic role in the overall control of the system than other
plans, and is more complex than a 2-port actuator, and prone to failure,
causing the whole system to stop working. It also limits you to 2 zones so
you can't, for example, have separate upstairs and downstairs heating zones
in addition to hot water. With S-Plan+ systems you can have as many zones as
you like.

See http://content.honeywell.com/uk/homes/systems.htm for information about
several different heating plans.

--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!