Siemens RDH10RF SET GB Room Thermostat

[daly]

Red and Blue are Live and Neutral, use to power the receiver.

The Yellow is the switched live and should go to L1

You then need a short wire link to connect the Red live across into the LX terminal.

The Earth wire is unused and should be made safe so it can't come into contact with any of the other wires.

(When the thermostat is calling for heat, LX is switched through to make L1 live which fires up the boiler and pump via the Yellow)

This is correct, but just to make it clear:

Old - Colour - New
1 ----- Red --- L
2 ---- Yellow - L1
3 ---- Gn/Yel - Not used; make safe, e.g a terminal block.
4 ---- Blue --- N

But it looks like this is live and neutral IN

Also, link L to Lx.

But atm red and blue are not connected the Live and Neutral at the boiler end they are connected to
5 = Blue neutral
4 = Yellow
3 = Red live
2 = Earth

 

[D_Hailsham]

This is correct, but just to make it clear:

Old - Colour - New
1 ----- Red --- L
2 ---- Yellow - L1
3 ---- Gn/Yel - Not used; make safe, e.g a terminal block.
4 ---- Blue --- N

Also, link L to Lx.

But atm red and blue are not connected the Live and Neutral at the boiler end they are connected to
5 = Blue neutral
4 = Yellow
3 = Red live
2 = Earth

The wiring I have given is at the thermostat, i.e old thermostat and new thermostat. The boiler wiring does not need to be changed.

 

[D_Hailsham]

But atm red and blue are not connected the Live and Neutral at the boiler end they are connected to
5 = Blue neutral
4 = Yellow
3 = Red live
2 = Earth

Just cottoned on to what you are saying

At the boiler, 3 is connected internally to L; and 5 to N.

 

[daly]

This is correct, but just to make it clear:

Old - Colour - New
1 ----- Red --- L
2 ---- Yellow - L1
3 ---- Gn/Yel - Not used; make safe, e.g a terminal block.
4 ---- Blue --- N

Also, link L to Lx.

Are you sure about this L to LX link, this will give me two permanent lives in the receiver end, sorry for the doubt but don't want to stuff it all up just because I misread your reply.

 

[jackthom]

I'm sure we're both sure about that link of Live to LX.

LX and L1 operate like the two terminals of a light switch, so Yellow will become Live when the switch goes ON.

 

[daly]

I'm sure we're both sure about that link of Live to LX.

Thank you for confirming that I will connect it up tomorrow.

 

[pauldoc2000]

I'm sure we're both sure about that link of Live to LX.

Thank you for confirming that I will connect it up tomorrow.

sorry to hijack this thread but I also have this Siemens thermostat to install.
Were the intsructions correct? did you install as described?
I have 3 wires in my exisiting thermostat which are-
permenant live
switched live
neutral
would I need to connect in the same way (ie with a link between L and LX)
my boiler is a potterton powermax HE