46
Filter
Clips
Aluminum
Filter
A09704
Fig. 40 -- Filter Installation (See through view)
Bottom
filter rack
Screw
(Note 4 and 5)
RIGHT SIDE
Evaporator
Coil
Top filter
rack
BENT COIL
Bottom
filter rack
Top filter
rack
Evaporator
Coil
STRAIGHT COIL
A09714
Fig. 41 -- Indoor Coil with Filter Rack
CONFIGURATION
Economizer Standard Sensors
OUTDOOR AIR TEMPERATURE (OAT) SENSOR—
The
outdoor air temperature sensor (HH57AC080) is a 10 to 20mA device
used to measure the outdoor--air temperature. The outdoor--air
temperature is used to determine when the Economizer can be used
for free cooling. The operating range of temperature measurement is
40 to 100
_
F (4.4 to 37.8
_
C). The sensor has 8 selectable temperature
changeover setpoints. The temperature changeover is set using 3 dip
switches on the sensor. The ABCD potentiometer on the controller
should be set to the “D” position. See Fig. 44.
SUPPLY AIR TEMPERATURE (SAT) SENSOR—
The supply
air temperature sensor is a 3 K
Ω
thermistor located at the inlet of the
indoor fan. See Fig. 42. The operating range of temperature
measurement is 0
_
to 158
_
F (--17.8
_
to 70
_
C). See Table 19 for
sensor temperature/resistance values. The temperature sensor looks
like an eyelet terminal with wires running to it. The sensor is located
in the “crimp end” and is sealed from moisture.
Table 19 – Supply Air Sensor Temperature/Resistance Values
TEMPERATURE
(
_
F)
CELSIUS (
_
C)
RESISTANCE (OHMS)
---22
---30
53,010
---4
---20
29,091
14
---10
16,590
32
0
9,795
50
10
5,970
68
20
3,747
77
25
3,000
86
30
2,416
104
40
1,597
122
50
1,080
140
60
746
158
70
525
Indoor
Blower
Supply Air Temperature
Sensor (SAT)
A09707
Fig. 42 -- SAT Location
LOW
TEMPERATURE
COMPRESSOR
LOCKOUT
SWITCH—
The Economizer is equipped with a low ambient
temperature lockout switch located in the outdoor airstream which is
used to lock out the compressors below a 42
_
F (5.6
_
C) ambient
temperature.
674D
--
--
A
Summary of Contents for Legacy 674D
Page 3: ...3 A09473 Fig 2 674D A24 36 Unit Dimensions 674D A...
Page 4: ...4 A09474 Fig 3 674D A42 60 Unit Dimensions 674D A...
Page 24: ...24 A10207C Fig 14 208 230 1 60 Connection Wiring Diagram Unit 674D 674D A...
Page 25: ...25 A10207L Fig 14 Cont 208 230 1 60 Ladder Wiring Diagram Unit 674D A 674D A...
Page 26: ...26 A10208C Fig 15 208 230 3 60 Connection Wiring Diagram Unit 674D A 674D A...
Page 27: ...27 A10208L Fig 15 Cont 208 230 3 60 Ladder Wiring Diagram Unit 674D A 674D A...
Page 28: ...28 A08019 Fig 16 Cooling Charging Table Subcooling 674D A...
Page 49: ...49 A10059 Fig 49 Economizer Wiring Diagram 674D A...
