Combi boiler room theremostat problem

[Chrisfa]

I have a ferroli optimax HE plus 31C combi boiler and I am trying to fit a Drayton RTS4 room stat.

There are only 2 wires that come from the boiler and when conected to the room stat terminals 2&3 nothing happens. This is a volt free stat. should it work with just those 2 connections? When looped together the boiler works fine.

 

[seco services]

1 com
3 call for heat.

 

[bengasman]

Vaillant manual shows you exactly how to do it.

 

[Chrisfa]

1 com
3 call for heat.

Tried that, still does not work must be a faulty stat.
Fitted a RT8 mechanical stat, now works fine,
thanks for your help.

 

[D_Hailsham]

Tried that, still does not work must be a faulty stat.

Doubt if it is faulty; you just wired it incorrectly!

The RTS4 needs a live supply to the L and N terminals; the boiler terminals connect to 1 and 3. Look again at the installation instructions.