System 350 A350E Electronic Cooling Control Product/Technical Bulletin
7
f. If the sensor’s resistance conforms to the chart
in Figure 8, reconnect the sensor to the control.
g. Reconnect power to the control.
Note:
Sensor reading indicated by the D350 may
differ somewhat from thermometer readings
due to sensor tolerances and time constants,
thermometer accuracies, and other factors.
°F
Temperature
260
240
220
200
180
160
140
120
100
80
60
40
20
0
-20
-40
500 700 900 1100
Resistance (Ohms)
1300 1500 1700 1900 2100
°C
120
100
80
60
40
20
0
-20
-40
Figure 8: Temperature vs. Resistance Chart
3. Check the A350E for proper operation.
Note:
Steps 1 and 2 must be performed first.
a. Set the minimum setpoint jumper to the Off
position.
b. Set the DIFF range to 5F° (2.8C°).
c. Adjust the setpoint dial to at least 10°F (-12.2°C)
above the sensor temperature (Ts) determined in
Step 2 (relay and LED should be Off).
d. Slowly decrease the setpoint until the control
relay and LED turn On, then slowly increase
the setpoint until the relay and LED turn Off.
e. If the relay does
not
perform as indicated in
Table 4, replace the A350E.
Table 4: A350E Relay Troubleshooting
LED
N.O. Relay
Status
Setpoint
Dial Setting
On
Closed
(Ts)* - Differential
Off
Open
(Ts)*
* (Ts) is sensed temperature.
For example:
70°F (Ts)
- 5F° (Differential)
65°F (Setpoint Dial Setting)
R
epairs and Replacement
Field repairs or calibration must not be made.
A99B Series sensors and replacement controls are
available through the nearest Johnson Controls
representative. See Tables 5 and 6 for ordering
information.
O
rdering Information
Table 5: System 350 Products
Item
Product Code
Number
Description
A350E Cooling Controls
(A350EA-4C Includes the
A99BB-25C Temperature Sensor)
A350EA-4C and
A350EA-1C
A350EA-2C
Range: 10 to 65°F (-12 to 18°C)
Adjustable differential: 1 to 30F° (0.6 to 16.7C°)
Range: 10 to 65°F (-12 to 18°C)
Differential: 2.5°F (1.5°C) fixed
For applications above 65°F (18°C), contact your Johnson
Controls representative.
Digital Temperature Sensor/
Setpoint Display Modules
D350AA-1C
D350BA-1C
Fahrenheit scale
Celsius scale
On/Off Stage Modules
S350AA-1C
S350AB-1C
Fahrenheit Scale
Celsius Scale
Slave Stage Module
S350CC-1C
Dual Scale (°F and °C)
Proportional Stage Module
S350PQ-1C
Dual Scale (°F and °C)
Power Module
Y350R-1C
120 or 240 VAC, 50 or 60 Hz input; Rectified Class 2,
24 VAC output