Many thanks to you all for making me focus on the pot. It suddenly dawned on me that the test sounder feature used full volume and I would need to set the system to hear the real volume (not alarm). After a few tries set it at just above zero and sounder is now tolerable,
Thanks again
Adrian
ps Yes I may be stuck in year 2000 but I can wire and programme the 9800/9800+in my sleep and while there are still spares around it does work fine.