If I have UFH downstairs and rads upstairs is it a 1 or two zone system?

[Northern monkey]

Hi sorry if the question sounds daft - I want to have a single circuit ( one thermostat) ufh system downstairs and radiators upstairs on a different thermostat.

 

there will be zone valves separating t he two (upstairs and down) 

 

im trying to understand the wiring required and I am wondering if I need a ‘multi zone controller’ or wether it can be done using the two thermostats wired to their respective zone valve so if heat is called from down then it opens down zone and operates boiler and then up valve stays closed etc

 

i hope that makes sense and any help as always is appreciated.

 

cheers

 

 

Edited October 8, 2019 by Northern monkey

[PeterW]

That is two zones so buy a three channel controller (assuming you need one for hot water too)

[Temp]

+1

 

The tricky part is generating the Boiler Enable (BE) signal that turns on the boiler. Something needs perform a logical OR function. In your case this would be..

 

BE = UFH or Rads or DHW.

 

You can't really do this by connecting all the stats together because you get unwanted interactions (for example the Rad stat might turn on the UFH loop pump). You can do it with relays but it's better to use some sort of controller.

 

Edit: Actually it might be possible to do it with just wire if the zone valves have contacts that make when the valve opens.

 

Edited October 8, 2019 by Temp

[Onoff]

6 hours ago, PeterW said:

That is two zones so buy a three channel controller (assuming you need one for hot water too)

 

That cheapo 3 channel controller you pointed me at a while back has been spot on thanks.

[ProDave]

8 hours ago, Temp said:

+1

 

The tricky part is generating the Boiler Enable (BE) signal that turns on the boiler. Something needs perform a logical OR function. In your case this would be..

 

BE = UFH or Rads or DHW.

 

You can't really do this by connecting all the stats together because you get unwanted interactions (for example the Rad stat might turn on the UFH loop pump). You can do it with relays but it's better to use some sort of controller.

 

Edit: Actually it might be possible to do it with just wire if the zone valves have contacts that make when the valve opens.

 

Easy.

 

Three individual 2 port motorised valves.  One for downstairs UFH one for upstairs radiators one for DHW.

 

The 3 channel time switch (plus a room thermostat if you wish for the 2 heating zones) turns on the motorised valves.  In the case of the UFH it turns on the downstairs motorised valve and the UFH mainifold pump.

 

Each of the motorised valves has a microswitch, connect all 3 of them in parallel. That gives the logical OR function to send a "call for heat" to the heat source.