sys boiler advice and how incorporate UFH with Y-Paln

[eandwal]

I've got a Honeywell Sundial "Y" plan system installed with vented cylinder and 12 year old boiler in kitchen.

New kitchen extension requires new condensing system boilder and I am looking at a Viessmann 200 with weather compensation and unvented cylinder to loose header and cold water tank. Also possibility of wet UFH in extension.

I am having problems in understanding how this will all fit together.

1) how to incroporate a zone of wet underfloor heating where I can have seperate control of the UFH besides the radiator heating? What plan would this be?

2) getting my head around the fact you would not normally have a room stat where weather compensation is used, correct? Dont want to keep going to boiler to turn heating on/off or increase temp a little if required, or is this where the remote control comes in?

3) can I still keep the pipework already installed going to the mid-point valve with pump moving inside system boiler?

I think Viessmann do a weather comp unit for three heating zones so maybe the UFH could go on the 2nd and the 3rd is left empty.

I haven't got a heating engineer in yet to quote as I wanted to know a little about what I was asking for.

thanks for any pointers

 

[glasgowgas]

first point= you have 3 zones. dhw, radiators, ufh

second point=look at a S Plan Plus set up

3 point= system boilers have an in built pump

fourth point= ufh is a blended htg system incorporating a mixer and ITS OWN PUMP for pedantic KP

 

[kevplumb]

3 point= system boilers have an in built pump

so should the ufh

 

[eandwal]

so would you not have a normal room thermostat when weather compensation is used because it uses a heating curve and outside temp sensor.

It therefore doesn't need to know internal temp and you tweak the curve untill you find a match for your house loses and flow temp that is comfortable, is that thinking right?

 

[glasgowgas]

so would you not have a normal room thermostat when weather compensation is used because it uses a heating curve and outside temp sensor.

It therefore doesn't need to know internal temp and you tweak the curve untill you find a match for your house loses and flow temp that is comfortable, is that thinking right?

it needs to know internal temp to shut off boiler when its not reqd

 

[kevindgas]

I've got a Honeywell Sundial "Y" plan system installed with vented cylinder and 12 year old boiler in kitchen.

New kitchen extension requires new condensing system boilder and I am looking at a Viessmann 200 with weather compensation and unvented cylinder to loose header and cold water tank. Also possibility of wet UFH in extension.

I am having problems in understanding how this will all fit together.

basically it won't
as glasgowgas has said you need to go with 3 zone valves (S Plan +)
a Yplan set up will not work