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Sensors
Discharge Air Temperature Sensor (DATS)
Installation of discharge air temperature sensor (DATS) must comply with the
following requirements:
• Installed downstream of the heat exchanger or electric heat elements.
• It must be placed in free airflow, where other accessories (such as humidifiers,
UV lights, etc.) will not interfere with its accuracy.
• Wiring distance between the integrated furnace and air handler controls
or damper control module and the discharge air sensor must not exceed
maximum distance as referenced in "Table 4. Terminals and Wiring
Recommendations" on page 4.
• DATS is highly recommended for all systems that include a variable capacity
outdoor unit in order to provided more precise dehumidification operation.
The included discharge air temperature sensor (88K38) monitors the supply
air. "Figure 2. Discharge Air Temperature Sensor Installation (Typical Up-Flow
Furnace)" shows the discharge air temperature sensor. This electronic sensor's
probe is inserted into the discharge air plenum to gather air temperature data
for the zone control module.
PLENUM
DAS Starting
11"
Point
Damper Control Module
Figure 2. Discharge Air Temperature Sensor Installation (Typical Up-
• When possible, position the sensor some distance away from the coil rather
than in the immediate coil area.
SENSOR
MOUNTING
11"
DETAIL
10 (254)
19
(486)
ECB
Electric
Heat
Strips
AIR HANDLER
SIDE VIEW
Flow Furnace)
• The DATS should be located at least 19 inches above the air handler unit
and 10 inches above cooling coil with a furnace.
• Locate the tip of the sensor 1/2 the depth of the plenum, and centered over
the discharge airflow, side- to -side in the discharge plenum
• Fasten the sensor bracket to the plenum with two self-tapping sheet metal
screws.
• Connect wires to DATS on damper control module, NOT on the Lennox
communicating indoor unit control.
NOTE: FOR UNITS WITH HUMIDITROL—Discharge air sensor temperature
(DATS) MUST be located on the output side of the EDA (if used; see
Humiditrol Zoning Accessory Installation 507944-xx).
If the DAT sensor has failed, shorted or not installed, iHarmony will only
operate in central mode. This mode is also indicated by the DCM central
mode LED being on. There is no notification by the thermostat for this issue.
Discharge Air Temperature Sensor (88K38) Temperature, Resistance
and Voltage Chart
Table 6. DATS Temperature / Resistance Chart
Front location preferred /
sides are optional
Sensor
°C
°F
-6.6
20
-3.9
25
coil
-1.1
30
1.7
35
FURNACE
4.4
40
SIDE
VIEW
7.2
45
10.1
50
12.8
55
15.6
60
18.4
65
21.2
70
23.9
75
26.7
80
29.5
85
32.3
90
35.0
95
5
IMPORTANT
VDC (Volts)
(ohm)
°C
46,134
1.513
46.2
39,869
1.425
49.0
34,520
1.335
51.8
29,936
1.247
54.5
26,104
1.161
57.3
22,764
1.077
60.0
19,842
0.993
62.8
17,406
0.916
65.7
15,294
0.842
68.5
13,442
0.772
71.3
11,849
0.706
73.9
10,501
0.647
76.8
9,282
0.589
79.7
8,233
0.537
82.2
7,322
0.489
85.1
6,523
0.445
87.8
Sensor
VDC (Volts)
°F
(ohm)
115
4,169
0.304
120
3,749
0.277
125
3,368
0.252
130
3,037
0.229
135
2,750
0.209
140
2,489
0.191
145
2,250
0.174
150
2,033
0.158
155
1,847
0.145
160
1,678
0.132
165
1,536
0.121
170
1,397
0.111
175
1,272
0.101
180
1,170
0.094
185
1,070
0.086
190
982
0.079
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