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118
Fan On Set Point (
F.ON
) is Head Setpoint On (
H.SP
) ex-
cept after a fan stage increase, when Head Setpoint On (
H.SP
)
is increased by Fan Stage Delta (
F.DLT
) for the Fan Delta Ac-
tive Time (
F.TME
). Using the factory default settings results
in the following values:
F.ON
=115.0 F (46.1 C) or following a
fan stage increase,
F.ON
=130 F [115.0 + 15.0 F] (54.4 C [46.1
+ 8.3 C]) for 60 seconds following the fan stage increase.
Fan Off Set Point (
F.OFF
) is Head Setpoint Off (
H.SP.F
).
Using the factory default settings results in the following value:
F.OFF
=72.0 F (22.2 C).
38APD025-060 — The 38APD025-060 units have common
fan control; both circuits share the same condenser fans. When
the highest SCT of both circuits is greater than
F.ON
, then an
additional stage of fan will be added to the current fan stage.
F.ON
will be updated for the required time. A fan stage will
decrease if the SCT for both circuit is less than
F.OFF
for 2
minutes.
38APS025-065 — For 38APS025-065 units, when the circuit
SCT is greater than
F.ON
, then an additional stage of fan will
be added to the current fan stage.
F.ON
will be updated for the
required time. A fan stage will decrease if the circuit’s SCT is
less than
F.OFF
for 2 minutes
38APD070 — The 38APD070 unit uses an additional fan
stage when the ambient temperature is less than 32 F (0 °C)
and only one circuit is on, Fan Stage 1. This fan stage turns on
the fans in the opposite circuit to draw a lower air volume
across the active circuit coils. (This fan stage is not used if
Motormaster
®
control is used.) When the circuit SCT is
greater than
F.ON
, then an additional stage of fan will be
added to the current fan stage.
F.ON
will be updated for the
required time. A fan stage will decrease if the circuit’s SCT is
less than
F.OFF
for 2 minutes.
38APD080-130 — The 38APD080-130 units have some fans
that are common between both circuits and some that are con-
trolled by each circuit individually. Initial fan stages are circuit-
specific fans and are controlled by the circuit’s SCT. When the
circuit SCT is greater than
F.ON
, then an additional stage of
fan will be added to the current fan stage.
F.ON
will be
updated for the required time.
The common fans are controlled by the circuit with the
highest SCT. If the next fan stage is a common fan stage and
one circuit’s SCT is greater than
F.ON
, the next fan stage will
be energized.
F.ON
will be updated for the required time.
A fan stage will decrease if the circuit’s SCT is less than
F.OFF
for 2 minutes.
Table 44 — Head Pressure Control Settings
Table 45 — 38APD,APS025-030 Fan Staging
*Items in either
Service Test
o
OUTS
or
Outputs
o
GEN.O
.
†Motormaster controlled motor, if equipped.
SETPOINTS
o
HEAD
ITEM
DISPLAY
EXPANSION
COMMENTS
H.SP
XXX.X °F (°C)
Head Setpoint On
Range: 85.0 to 120.0 F (29.4 to 48.9 C)
Default: 115.0 F (46.1 C)
H.SP.F
XX.X °F (°C)
Head Setpoint Off
Range: 45.0 to 90.0 F (7.2 to 32.2 C)
Default: 72.0 F (22.2 C)
F.ON
XXX.X °F (°C)
Fan On Set Point
Calculated value, cannot be changed
F.OFF
XXX.X °F (°C)
Fan Off Set Point
Calculated value, cannot be changed
F.DLT
XX.X
'
F (
'
C)
Fan Stage Delta
Range: 0.0 to 50.0
'
F (0.0 to 27.8
'
C)
Default: 15.0
'
F (8.3
'
C)
F.TME
XXX secs
Fan Stage Active Time
Range: 0 to 300 seconds
Default: 60 seconds
UNIT
OPERATING CIRCUIT
FAN STAGE
OUTPUT POINT NAME*
CONTACTOR FANS ENERGIZED
38APD025,027,030,
38APS025, 027,030
With or Without Motormaster
Controller
A (38APS)
A or B (38APD)
1
FAN1
FC1
OFM1†
2
FAN1
FAN2
FC1
FC2
OFM1†
OFM2
CONTR
OL BO
X
OFM1
OFM2