Three port valve question

[doitall]

depends on how its plumbed up, you dont need a 2 port valve to control the ufh,

utter rubbish!! unless you use a zone valve on each circuit there is nothing to stop the flow being drawn through that circuit when another is running (you would have a similar effect as you get in a gravity hot water circuit)

I take it you dont install ufh then! what do you think the actuators are for? on many ufh systems the thermostats control the actuators which (through a relay )switch on the boiler, the 2 port valves are used to block any zones not needed, when a three port valve is used for rads/cylinder a blocking 2 port valve has to be used because 1 of the ports on the 3 port is always open . sheeeeeesh.

I always use 3port diverter valves on underfloor heating, with a separate pump on controlled temperature circuits.

 

[kevindgas]

as i said all along if as the OP said in his 1st post this has been done in the last few weeks then it should have been thought out more carefully as to put a mid pos valve in to a new system of this kind shows some kind of muppetry on the installers part.

and to answer the other question no i don't install the underfloor part but i do pipe the rest up including 2 boiler, 2 pump 5 valve set ups

Vaillant 428 and 438 in parrallel supplying the whole system via a 25/80 pump to the heating/hot water and a 15/50 supplying the UFH all 3 zones with a zone valve and both boilers with zone valves allowing usage of either or both boilers into any or all of the 3 zones is just a recent install.