Should be straightforward, but.....

polo1 · Sep 19, 2017

Changing a faulty Drayton SM1 mechanical programmer with a Siemens RWB 1007 programmer (both single channel) serving a Ferroli DOMIcompact F24D combi boiler.

System appears to wired - mains, programmer, thermostat, boiler. The original back plate serving the Drayton had a link between L & 1, with the thermostat feed in 3. Keeping this arrangement with the Siemens, the thermostat (and hence the boiler) has a permanent feed even when the programmer is switched off.

Tried various permutations, but only ever get perm feed to thermostat with the programmer off, or no power to thermostat, irrespective of the setting of the Siemens programmer.

Confused!

buzzlightyear · Sep 19, 2017

http://w3.siemens.co.uk/buildingtechnologies/uk/en/building-automation/residential-controls/documentation/Documents/Siemens RWB1007 datasheet.pdf http://www.gasapplianceguide.co.uk/Drayton PDF/Drayton SM1 and SM2 install and prog.pdf posted this for you .

Leesparkykent · Sep 19, 2017

polo1 said:
Changing a faulty Drayton SM1 mechanical programmer with a Siemens RWB 1007 programmer (both single channel) serving a Ferroli DOMIcompact F24D combi boiler.

System appears to wired - mains, programmer, thermostat, boiler. The original back plate serving the Drayton had a link between L & 1, with the thermostat feed in 3. Keeping this arrangement with the Siemens, the thermostat (and hence the boiler) has a permanent feed even when the programmer is switched off.

Tried various permutations, but only ever get perm feed to thermostat with the programmer off, or no power to thermostat, irrespective of the setting of the Siemens programmer.

Confused!

Perm live to 2 and switch live to boiler from 4. If you look at the manual it says if using 230V switching then link live to 2. 1 and 3 is used for the permanent live to the boiler and is normally closed so it disconnects the boiler when the service interval timer kicks in and opens the contact between 1 and 3. This way the boiler can't be used until it's serviced and reset.

MJPD29 · Sep 19, 2017

Most of the programmers require a link for 230v

polo1 · Sep 20, 2017

Thanks all. After a bit more head scratching, I discovered that one of the programmer pins was not making proper contact with the backplate connection ( serves me right for not replacing the backplate!).
Now sorted & working.