I had a four story dorm that I cared for that was heated by steam. The kids on the top floor would turn the radiators ALL the way up and open their windows in the 0° F weather. The 8 averaging sensors would become low enough to call for heat all of the time, but the chimney effect would FREEZE out the rooms on the ground floor. That fresh smokey air that was LEAVING the top floor was being replaced by the freezing air coming in the bottom floor, through old windows.
Turning up the setpoint actually made the difference between the top floor and the bottom floor WORSE!
Of course, the DDC system was heavily investigated and trended to see if IT was the problem. I was told not to touch it....
It recorded changes in setpoints and status.
It didn't record offsets being added or subtracted from sensor inputs.
I made the thing think the building was 79°, one sensor at a time. The steam boiler shut off. It stayed off.
The windows began coming down. Slowly at first, then all at once.
I reset the offsets. Had to do that for three weeks, every day, EVERY FALL, to train the little buggers to close the damned windows when they went out.
After that, except once in a while, most of the windows would stay shut. The ones that didn't stay shut, I'd be sure to knock hard on their door EVERY TIME I was on that floor, to remind them. They didn't care for that. No, not one bit.
Finding a way to do it from the main building without leaving tracks was the hard part.
It was an XBS Excell 5000 system, without naming names.
[Edited by Noel Murdough on 02-11-2005 at 06:19 PM]