Adding a UFH zone to a Y Plan system

[Rhodp]

Hi,
I'm looking to add a UFH zone to my current CH and DHW system that runs on a Y plan. I'm not a plumber or electrician and all the info I can find on the net seems to suggest going to an S plan to make the three systems independent. The electrician I'm using is suggesting just tieing the UFH zone valve to the boiler directly. I'm going to get his detailed plan tomorrow but thought I'd ask for advice first. Looking at the wiring diagrams I think he's going to suggest getting the zone valve Motor power controlled from the UFH stat, the Grey normally open from the UFH 230v input and then send the Orange common contact to the boiler. A call for heat from teh UFH stat would then open the zone valve and fire up the boiler and pump but shouldn't activate the 3 way valve on the existing system. Am I missing somehitng obvious? Firstly any comments on whether I need to go to S plan and secondly does my reading of the wiring make sense and would that work the three systems independently?
Cheers for any advice. Rhodp

 

[migoplumber]

your underfloor heating zone will need its own zone and mixer valve, so that the temperature running through the manifold will be set at 60 degreed. generally has its own pump as well.
check out hep2o webpage for schematics, and adapt them to your needs.

shaun