Wiring - Replacing Siemens RWB7 with Siemens RCR10 thermostat

[scott7824]

Hello

Not sure if anyone can help.

I have bought a new thermostat to replace an existing programmer. I hoped (wrongly!) that if I got the same make it would be a simple case of connecting 1 to 1, 2 to 2 etc, never that easy.

Would anybody know what wires go where (eg 2 to L1)? I have attached a couple of photos of the existing setup and the new receiver. Also, there does not seem to be a connection for the earth, is this correct?

Many thanks!

Scott

 

[scott7824]

Hi all

After doing a bit of research I was thinking the following would work, do you think it looks correct?....

L > L
N > N
2 > LX
4 > L1

Also, no earth is required for the new unit.

Many thanks in advance

Scott

 

[picasso]

Unless I have got the wrong idea of what your doing you can't replace a programmer with a thermostat, they do different jobs in your heati g system,
What type of heating system do you have that needs a chentral heating off connection?

 

[scott7824]

Morning Picasso, many thanks for he reply.

Basically, we want to remove the programmer (we never have used them in previous homes, just turned the heating up when we get in).

We can then just control the heat with a thermostat to stay on a constant temperature and to keep a minimum temperature when we are away weekends etc.

At the moment the heating is either on or off, so it just gets hotter and hotter and also we are worried about pipes freezing if we are away.

The system is a Grant combi 90, I guess about 10 years old.

Many thanks again

Scott

 

[picasso]

You could disregard 2 on the programmer and link L and LX on the new stat, is live and 2 linked on the old programmer?

 

[scott7824]

Thanks again Picasso, there are 3 3-core cables coming from the wall, 2 go to N and L on the old backplate, the third 3-core cable goes to 2 (brown) and 4 (blue).

I hope this makes sense?

Scott

 

[picasso]

2 on the old programmer is ch off, I have no idea why that would be connected, 4 is switched live to boiler so I would trace what 2 is connected to before fitting new stat.

 

[scott7824]

Unfortunately the way the boiler has been installed (its floor standing, against the wall with the cables going into the back) it looks very hard to trace the cables, which I know would be ideal.

Do you think I may need to call and electrician as don't want to damage the boiler with a wrong install.

I though this would be an easy job, reconnecting like for like etc, oh well!

Thanks again for taking time to help.

Scott