International comfort products CAS090 G Series Installation Instructions Manual page 30

Wind baffles are required to prevent wind cross currents
from causing abnormally low condensing temperatures.
Use 20- - gauge sheet metal to fabricate wind baffles (see
Fig. 27 and Table 11).
Operation —
Fan on/off control in cooling- - only units is provided by an
outdoor fan relay (OFR).
In cooling mode, fan motor speed of outdoor motors
OFM1 and OFM3 is regulated by the speed control
temperature sensor on outdoor coil 1 for a minimum coil
condensing temperature of approximately 100_F (38_C)
at higher outdoor ambient temperature and 80_F (27_C) at
lower ambient. Additionally, outdoor fan motor OFM2
and OFM4 are turned on/off by the low ambient
temperature switch, LAS, operating the low ambient relay
(LAR). The LAS control temperatures are open 42_F +/- -
5_F, close 57_F +/- - 5_F (open 5.5_C +/- - 2.8_C, close
13.9_C +/- - 2.8_C).
To override the speed control for full fan speed operation
during service or maintenance, either:
a. remove sensor and place in hot water >120_F
(>49_C), or
b. rewire to bypass control by connecting speed
control input and output power wires.
30
Troubleshooting —
OBSERVATION
Fans won't start
Cooling --- Center outdoor
fans (OFM2, OFM4) off
below approximately 60_F
(16_C) outdoor ambient.
Cooling --- Center outdoor
fans (OFM2, OFM4) not on
above approximately 60_F
(16_C) outdoor ambient
Cooling --- Slow fan speed
for outer fans (OFM1,
OFM3) at start or during
low outdoor ambient
Cooling --- Slow fan speed
for outer fans (OFM1,
OFM3) above 85_F (29_F)
outdoor ambient (should
be full speed)
Cooling --- motor current
into speed control is
greater than motor name-
plate FLA
Speed Control Sensor Resistance —
_F +/---2_F_
Specifications are subject to change without notice.
POSSIBLE REMEDY
All fans:
Check power & wiring
Check outdoor fan relay (OFR)
OFM1, OFM3 only:
Check speed control sensor location
Check speed sensor resistance
OFM2, OFM4 only:
Check low ambient switch (LAS)
Check low ambient relay (LAR)
Normal operation
Check low ambient switch (LAS)
Check low ambient relay (LAR)
Normal operation
Check speed control sensor location
Check speed control sensor
resistance
Check fan motor capacitor
Normal operation
Up to 30% higher A at partial speed
at low ambient
TEMPERATURE
_C +/---1C
--- 22 --- 30
--- 4 --- 20
14 --- 10
32 0
50 10
68 20
77 25
86 30
104 40
122 50
140 60
158 70
RESISTANCE
Ohms, nominal
88350
48485
27650
16325
9950
6245
5000
4028
2663
1801
1244
876
501 01 3600 01