This may work unless you are after an older model:

http://www.industry.siemens.co.uk/buildingtechnologies/uk/en/building-automation/residential-controls/documentation/Documents/rwb29_i.pdf

You could always contact Landis & Gyr

http://www.landisgyr.com/contact/

acp
March 2017

There's a search feature on this page in the top right corner - searches for RWB-XP show 8 requests for the manual you seek over the past 10 years - none of them successful.

Google searches for the operating instructions were not easy - but I did find this...
http://unafwo.lflink.com/landis-gyr-rwb-xp-manual/

I have no confidence in the web page - I did not follow the link

Your question is in the Oil Filled Radiators category

Good Luck...
March 2017