Carrier WeatherExpert 48N2 - Page 58

58
90-105 Ton Standard Efficiency (identical to 75 Ton High Efficiency)
Circuit B
Contactor OFM(s)
Coils
Software Board Conrolled Controlled
A CONDFAN1 MBB Rly 6 OFC1 OFM2 Comp A1, A2, or A3 ON B CONDFAN2 MBB Rly 5 OFC2 OFM5 Comp B1, B2, or B3 ON
Common CONDFAN3 RCB Rly 1 OFC3 OFM1,6 Circuit A or B SCT or OAT Common CONDFAN4 RCB Rly 2 OFC4 OFM3,4 Circuit A or B SCT or OAT
# of Fans ON
Fans ON # of Fans ON Fans ON
Stage 1 OFC1 1 OFM2 Stage 1 OFC2 1 OFM5 Stage 2 OFC1,3 2 OFM1,2,6 Stage 2 OFC2,3 2 OFM1,5,6 Stage 3 OFC1,3,4 3 OFM1,2,3,4,6 Stage 3 OFC2,3,4 3 OFM1,3,4,5,6
Low Ambient Prestart 1 (OAT ≤ 50F) = Stage 1
Circuit A
Low Ambient Prestart 2 (50F < OAT < 70F) = Stage 2
Coils
High Ambient Prestart (OAT ≥ 70F) = Stage 3 High Saturated Condensing Temp (SCT>130) = Stage 3
Stage down allowed if SCT<SCT_MIN Stage up allowed if SCT_MAX<SCT<130 Current stage if SCT_MIN<SCT<SCT_MAX
Circuit B Coils
90-105 Ton High Efficiency (identical to 150 Ton Standard Efficiency)
Contactor OFM(s)
Software Board Conrolled Controlled
A CONDFAN1 MBB Rly 6 OFC1 OFM2
Common CONDFAN2 MBB Rly 5 OFC2 OFM5
B CONDFAN3 RCB Rly 1 OFC3 OFM8
Common CONDFAN4 RCB Rly 2 OFC4 OFM3,7 Common CONDFAN5 RCB Rly 3 OFC5 OFM1,4,6,9
Circuit A Coils
Allow Fan Staging if OAT < 70F and:
See 150 Ton Standard Efficiency
Circuit
Controlling Output
Logic
Circuit A
Circuit B
Comp A1, A2, or A3 ON
Comp B1, B2, or B3 ON
Circuit A or B SCT or OAT
Circuit A or B SCT or OAT
Circuit
Controlling Output
Logic
Circuit A or B SCT or OAT
POWER BOX
3
MM
2
9
MM
8
A3
A2
B2
B1
B3
1
7
6
5
4
A1
POWER BOX
3
MM
2
6
MM
5
A3
A2
B2
B1
B3
1
4
A1
Fig. 11 — 90, 105 Ton Unit Condenser Fan Staging Sequence
a48-8697
LEGEND
MM — Motormaster OAT — Outdoor Air Temperature OFC — Outdoor Fan Contactor OFM — Outdoor Fan Motor