Replacing a room thermastat

[how many wires?]

Need some help with this one please!

I'm replacing an old Honeywell room dial thermastat with a Siemens RDD10. The Honeywell uses 3 wires (Red,Blue,Yellow) with the Red going into the terminal marked 1, Blue into 2 and Yellow into 3.

Now the new thermastat has a wiring diagram but I'm no electrician so can't make head nor tale of it. I had a plumber install one of these at my old house and he told me that it only needs 2 out of the 3 wires and the odd one gets taped up. If you get them in the wrong order it blows your heating timer.

I just need to know which wires go where on the new stat and which one is not used! The new stat has 3 terminals marked 1-3.

I can take some pics of the wiring diagram and stat if it helps, I'll have to email to an admin as I don't have a site.

Any help much appreciated.

thanks

____________________
moderator

pictures! please see this

 

[pdcelec]

Is it the RDD10 or the RDD10.1. There is very important distinction!

 

[how many wires?]

It's the 10.1 model, there are some pictures at the following link (thanks to Dewy and the moderator who pointed me in the right direction)


http://photobucket.com/albums/b357/howmanywires/

any ideas??
________________
moderator

anytime

 

[BJS_Spark]

Honeywell t6360

1 - Red (Permanent Live)
2 - Blue (Neutral)
3 - Yellow (Switched Live)

RDD10.1

Q11 - Red (Permanent Live)
Q12 - Yellow (Switched Live)
Blue (Neutral) must be terminated off safely as not used

This is assuming the Honeywell was wired correctly. I would start by checking the wire's measuring between red and yellow - there should be no volts.
If this works but the operation is reversed then swap yellow to Q14

 

[pdcelec]

BJS has beat me to it. Too early for me on Sunday morning.