I am still confused about my user code?

It wouldn't turn the alarm off which ran for the full 20 mins.

Sometimes momentary panic causes us to do things incorrectly, remembering, pressing buttons etc ?

your code wont stop the externel bell ringing IF it thinks its wires have been cut (blown fuse) as the panel is not driving the bell, the sounder is driving itself as it thinks the panel is being attacked.

your code wont stop the externel bell ringing IF it thinks its wires have been cut (blown fuse) as the panel is not driving the bell, the sounder is driving itself as it thinks the panel is being attacked.

QFA

If you have blown the fuse you code will not stop the external sounder but it should silence the internal.

Replace the fuse and all should return to normal as long as you haven't still got a short on the PIR cable.

Sometimes momentary panic causes us to do things incorrectly, remembering, pressing buttons etc ?

But not when the 12-volt power to bell is still off ... senior moment

Should I check the wiring in the PIR before I replace the fuse or after?

If I check before wont it just set the alarm off again for 20 mins? If I do it after wont it set the alarm off for 20 mins??!!

What is the correct sequence/ way for powering down to safely work on PIR's, I have to move some others for decorating as well?

Should I check the wiring in the PIR before I replace the fuse or after?

If I check before wont it just set the alarm off again for 20 mins? If I do it after wont it set the alarm off for 20 mins??!!

What is the correct sequence/ way for powering down to safely work on PIR's, I have to move some others for decorating as well?

Check wiring before replacing fuse.

Power down?? Youre asking for disabeling info.

on a better panel the sounder and the pir's would be fed from seperate fuses.

Should I check the wiring in the PIR before I replace the fuse or after?

Before, or buy loads of fuses

If I check before wont it just set the alarm off again for 20 mins? If I do it after wont it set the alarm off for 20 mins??!!

Nope

What is the correct sequence/ way for powering down to safely work on PIR's, I have to move some others for decorating as well?

Enter engineering, remove power links to PIR`s.

Or call someone capable, perhaps an engineer.

Check the PIR for shorts first, if it's not wearing any replace the fuse.

The worst that is likely to happen is that the fuse will blow and the external will ring for another 20 minutes.

Warn your neighbors first to avert any annoyance.

I appreciate I could be an intruder asking for disabling info!

I just want to put the system back working again.

Two questions which hopefully wont give you security concerns!!

At the moment the sysyem is on, is unarmed, and has the tamper light on. If I do nothing for the rest of the day, it is not likely to go off again is it?

I caused the problem and it rang the bells for 20 mins, hopefully it can't do it again until it is fixed?

I assume the safe way of working is to open control panel, alarm goes off, turn alarm off quickly with user code, leave control panel open and then work on PIR's?