s plan with underfloor without zone valve.

[j-lextricks]

Evening all,

I'm in the midst of connecting above system, the plumber is adamant it will work without a 2 port but I'm struggling to make sense of it. I've got a system boiler with s plan and a single zone UFH manifold. Could anyone please give me some pointers re wiring without the back feed I'm experiencing at the moment from heating/DHW. I know a relay's an option....

Cheers. Joe.

 

[davesparks]

Put a relay in to cure a backfeed

 

[Leesparkykent]

As above a relay.

 

[bigspark17]

Do you have a 2 core going back to boiler.? Is ur ufh room stat 240v or 12v.?

 

[j-lextricks]

I've got a 3 core and earth from wiring centre to manifold and a 240v wireless stat controlling ufh pump/ sw live back to boiler.

 

[bigspark17]

Not 100% clear of your set up. Try take ufh pump off brown on motorised valve not orange!

 

[j-lextricks]

Hi Bigspark, thanks for replies. I've got 2 2 ports controlling rads and DHW, but no valve for UFH. Wireless stats for both Rads and UFH.

 

[davesparks]

Not 100% clear of your set up. Try take ufh pump off brown on motorised valve not orange!

Bad idea, if the valve fails to open for any reason the pump will burn itself out working against the closed valve.

Plus there isnt a valve there!

 

[Leesparkykent]

You need a relay for the UFH pump...simples

 

[bigspark17]

Hi Bigspark, thanks for replies. I've got 2 2 ports controlling rads and DHW, but no valve for UFH. Wireless stats for both Rads and UFH.

No valve then you need a contactor.

 

[davesparks]

A relay will be fine, no need for the noise of a contactor

 

[j-lextricks]

Thanks all for your help

Much appreciated.

 

[EvilDrPorkChop]

You could do this if you use a UFH actuator with 4 wires rather than the usual two wires. They have a microswitch in them like the 2 Port valves. Usually you would always put a 2 port valve on the UFH (Especially a single zone as then you'd need no actuators).

 

[hanky-pankysex]

If your using an ufh wiring centre then a 2 port valve is not required, when an ufh room stat calls for heat it will open an actuator, fire the ufh pump then using the volt free relay built into the wiring centre send a signal to the boiler, the boiler will only send heat to the ufh as the other zone valves are closed. When the ufh is not calling for heat the actuators will close down, the system should have an auto bypass installed to cope with pump overrun