What to check
In order to get power to the CISA lock on the door, a pair of spring door contacts flush in the door frame may be fitted.
These spring loaded contacts move the electrical wire connections and can break off, so check the connections behind the spring contacts.
Corrective Action
Reconnect.
Or fit a Door Loop
Additional notes
DL-W white
DL-B brown
DL-ARM armoured tube
Links
https://www.entryphone.co.uk/shop/productdetail/DL-W
https://www.entryphone.co.uk/shop/productdetail/DL-B
https://www.entryphone.co.uk/shop/productdetail/DL-ARM-12