Carrier 48FP - Page 58

58
Table 51B — Head Pressure/Fan Cycling Control (088 and 104 Sizes)
CONTROL OUTPUTS
LEGEND
UNIT CONFIGURATION
MOTOR
LOCATION
CIRCUIT:
MOTOR ID NO.
OFM ON OFM OFF
Standard
(with standard SCT sensors)
(MMAS = Yes)
(TRNS = No)
First Stage
A: 1
B: 2
SCT > (HPSP – 15 F) SCT < (HPSP – 37 F)
for 90 secs AND
Second Stage motors OFF
Second Stage
A: 3, 5
B: 4, 6
SCT > HPSP
(start delayed 60 secs after
start of compressor, unless
SCT > 143 F)
SCT < (HPSP – 35 F) for two
minutes
With Accessory Sensors
(Pressure Transducers
and Suction Thermistors)
(MMAS = Yes)
(TRNS = Yes)
(SUSN = Yes)
First Stage
A: 1
B: 2
SCT > 138 F SCT < (HPSP – 37 F) for 90
secs AND
Second Stage motors OFF
Second Stage
A: 3, 5
B: 4, 6
SCT > HPSP
(start delayed 60 secs after
start of compressor, unless
SCT > 143 F)
SCT < (HPSP – 35 F)
for two minutes AND
superheat greater than
30 F for two minutes
Motormaster® Disabled
(MMAS = No)
First Stage
A: 1
B: 2
On with compressor Off with compressor
Second Stage
A: 3, 5
B: 4, 6
SCT > HPSP SCT < (HPSP – 35 F)
for two minutes
MOTOR GROUP/CIRCUIT CHANNEL RELAY CONTACTOR
First Stage/A
PSIO2 47 MMR-A MMC-A
First Stage/B
PSIO2 46 MMR-B MMC-B
Second Stage/A
DSIO1 29 — OFC-A
Second Stage/B
DSIO2 30 — OFC-B
DSIO
—
Relay Module
HPSP
—
Head Pressure Set Point
MMC
—
Motormaster® Contactor
MMR
—
Motormaster Relay
OFC
—
Outdoor-Fan Contactor
OFM
—
Outdoor-Fan Motor
PSIO
—
Processor Module
SCT
—
Saturated Condensing Temperature