Cheers Wiz,
Strike plate looks the same, coded lock is CL-201-SC. The door set is in good order.
I've tried talking to the installers, not got past the switchboard - no -one available. Just want them to report on the ACTUAL fault.
Thanks for all your help
From what you are saying I really think there is pressure on the strike so it won't release but there could be other, more serious problems.
If I was you I would:
1) Get them to confirm that the strike is a fail-safe version - Ask them to check, with the door open, that if they totally disconnect the power supply that feeds the door strike circuit, that the strike releases using finger pressure. Then power the power supply back up again and get them to check, with finger pressure, that the strike is now locked. If all this is o.k., go to step 2. If the strike never releases the solenoid is jammed (faulty - needs replacing) or more worryingly it is a fail-locked instead of fail-safe strike. (go to step 3)
2) Close the door and disconnect the power once again. Check that the door releases. If it doesn't try pushing the door against the closed position a bit, to take the opening pressure off the strike, and see if it releases then. If it does, it means the strike is poorly fitted or the door is warped (adjust position of strike to suit or replace with CDV firelock or face-to-face maglock (the maglock won't work with the existing mechanical keypad and an electrical keypad will need to be added))
3) (follow on from step 1 and with power supply connected) Open door and operate fire alarm, if strike now releases on fire alarm with finger pressure, it is a fail-locked version and urgently needs replacing with a fail-safe version and also possibly re-wiring of fire alarm interface circuit to suit. If this is the case, also check all other similar doors in building.
4) Once the system is operating correctly and as fail-safe. If keypad side of door is on an escape route (I presume that the other side has a handle that you can open the door without using a keypad) install green emergency door release unit as a normally-closed switch in the electrical feed to the electrical strike.
5) If unauthorised operation of the green emergency door release unit is a problem, consider installing an alarmed poly lift up cover over the green emergency door release unit