[Nut-upsuser] Centos 6.1, BNT400AP and immediate shutdown of ups

[WK]

I'm new to the list.
Hello.

I just googled and tried some general news lists.
There is hard to compose good question to google, cause shutdown and 
poweroff are standard ups jobs.
Then.

I've upgraded some computer Centos 5.3 to Centos 6.1.
It is powered with Powercom BNT-400AP ups.

A problem is, when I try to start upsdriver - powercom.
While connecting to the ups (via ttyS) it (powercom driver) causes ups 
poweroff.
Perfect black-out. UPS is going out.

I tried to debug it connecting LCD instead of computer.
LCD load is about 15 Watt.
And then anything worked perfectly (upsmon, upssched, automatic shutdown 
etc.).

When I connected computer back and tried to start powercom drivetr, I 
again got ups poweroff.
Computer has 4 hdds - its load is >100Watt.
But ups is still wired - even with empty batteries it shout work with 
any load until I unplugg it?

Has anybody some other ideas?
-- 
Wieslaw Kierbedz