Hired-Hand Emergency Back-Up and Alarms: Secondary Sensing System Expansion - Manual (Page 21)

Manual No. 4801-3001 Rev 7-08 Secondary Sensing System Expansion 21 of 46
9.1.2 Emergency Operation
In this mode of operation, the system still maintains the temperature as it does in Normal Operation. In
addition, it will begin running the first cooling stage (Cool 1) on a 5 minute timer. The timer percentage is
determined by the setting in P3 (Emergency Timer Percentage). This mode of operation is entered if
communication is lost between the master controller and the S
3 . In this case, the S 3 assumes that the master
controller is lost and tries to maintain the minimum ventilation until someone recognizes the problem.
Emergency Operation is indicated by an “LnE” flashing in the display of the S
3 . The alarm relay on the S 3
is also engaged in this mode operation.
9.1.3 Override Operation
In this mode of operation, the system still maintains the temperature as it does in Normal Operation. In
addition, it receives commands from the master controller to turn on certain stages of heating or cooling.
There are many different circumstances that could cause this to happen, in this manual, we will list one of
the most common. For example, if communication were lost inside the EV-3000, the master controller
would be unable to turn the appropriate stages on in the usual way. Therefore, the master controller would
communicate to the S
3
and indicate which stages that it is trying to turn on. At this point, the S
3
would
obey the command and turn the appropriate stages on. For this mode of operation to work to its fullest
potential, care must be taken to insure that the stage jumpers on the relay strips match the stage setting in
the master controller (Refer to Section 13.9). Override Operation is indicated by an “LnO” flashing in the
display of the S
3 Expansion Back-Up System. The alarm relay is also engaged in this mode of operation.
“Ln0” flashing
in the Display
“LnE” flashing
in the Display