CEMP-E
TI 811-12
18 August 1998
Table 7-1. Damper Modulation for Cold Deck Systems.
Condition No.
Description
Control
1
OA temperature
Modulate OA, RA, and relief
< SA temperature
dampers to maintain mixed air
< Changeover temperature
temperature at cold deck supply
temperature setpoint minus 2
degrees F.
2
SA temperature
Set OA and relief dampers at
< OA temperature
100% open; RA dampers closed.
< Changeover temperature
3
SA temperature
Set OA and relief dampers at their
< Changeover temperature
minimum positions, and set RA
< OA temperature
damper at its corresponding open
position.
c. Single Zone Type Systems. For single zone type systems, the UMCS shall modulate the OA,
RA, and relief dampers based on the conditions shown in Table 7-2.
Table 7-2. Damper Modulation for Cold Deck Systems.
Condition No.
Description
Control
1
OA temperature
Modulate OA and relief dampers
< Changeover temperature
open, and the RA dampers closed
to maintain the space temperature
cooling setpoint.
2
Changeover temperature
Set OA and relief dampers at their
< OA temperature
minimum positions, and set RA
damper at its corresponding open
position.
d. Damper Controls. The OA, return air and relief air dampers are positioned by the UMCS (for
direct digital control implementation) or by local loop control (for supervisory control implementation) to
maintain the required mixed air temperature. Design requirements for this applications program will be
indicated by the letter X adjacent to the program listing on the appropriate database table, as shown in
Chapters 8 and 9.
(1)
Field hardware requirements. The hardware requirements are:
(a)
UMCS inputs from utility system.
1/
OA intake damper position feedback - one per OA damper.
2/
OA dry bulb temperature.
3/
Mixed air temperature.
4/
Return air temperature.
(b)
UMCS outputs to utility system.
7-4
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