JOHNSON CONTROLS
162
FORM 150.72-NM1 (1020)
Unit Operation
TABLE 18 – YLAA STANDARD CONDENSER FAN CONTROL USING DISCHARGE PRESSURE ONLY
(5 OR 6 FANS PER SYSTEM)
FAN
STAGE
ON* OFF**
IPUII I/O OUTPUT FAN CONTACTOR FAN #
SYS 1 SYS 2 SYS 1 SYS 2 SYS 1 SYS 2
1
DP >
PROGRAMMED
FAN CONTROL
ON PRESSURE
DP <
PROGRAMMED
FAN CONTROL
ON PRESSURE
MINUS
PROGRAMMED
DIFFERENTIAL
PRESSURE
TB7-8 TB10-8 1-KF1 2-KF1 1-MF1 2-MF1
2
DP >
PROGRAMMED
FAN CONTROL
ON PRESSURE &
FAN STAGE 1 IS
ENERGIZED
DP <
PROGRAMMED
FAN CONTROL
ON PRESSURE
MINUS
PROGRAMMED
DIFFERENTIAL
PRESSURE &
FAN STAGE 1
IS ENERGIZED
TB7-8 &
TB7-9
TB10-8 &
TB10-9
1-KF1 &
1-KF2
2-KF1 &
2-KF2
1-MF1 &
1-MF2 &
1-MF3
2-MF1 &
2-MF2 &
2-MF3
3
DP >
PROGRAMMED
FAN CONTROL
ON PRESSURE
AND FAN
STAGES 1 & 2
ARE ENERGIZED
DP <
PROGRAMMED
FAN CONTROL
ON PRESSURE
MINUS
PROGRAMMED
DIFFERENTIAL
PRESSURE &
FAN STAGES
1 & 2 ARE
ENERGIZED
TB7-8 &
TB7-9 &
TB7-10
TB10-8 &
TB10-9 &
TB10-10
1-KF1 &
1-KF2 &
1-KF3
2-KF1 &
2-KF2 &
2-KF3
5 FAN:
1-MF1 &
1-MF2 &
1-MF3 &
1-MF4 &
1-MF5
6 FAN:
1-MF1 &
1-MF2 &
1-MF3 &
1-MF4 &
1-MF5&
1-MF6
5 FAN:
1-MF1 &
1-MF2 &
1-MF3 &
1-MF4 &
1-MF5
* When a fan stage is turned on, the pressure for the next stage is increased 20 PSIG and ramped back to the programmed on pressure over
the next 20 seconds.
** When a fan stage is turned o󰀨 (Programmed ON pressure minus the di󰀨erential), the OFF pressure for the next stage is decreased 20 PSIG
and ramped back to the programmed OFF pressure minus the di󰀨erential.
The time delay (fan delay timer) be-
tween turning fan stages on and o is
xed at 5 seconds.