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FANs 930, 930.5, 125, 121

Product/Technical Bulletin A350

Issue Date 0899

© 1999 Johnson Controls, Inc.

1

Part No. 24-7664-44, Rev. C

www.johnsoncontrols.com

Code No. LIT-930010

The A350A/B Series is an on/off electronic
temperature control with a Single-Pole, Double-Throw
(SPDT) relay output and a Light-Emitting Diode (LED)
relay status indicator. Designed to operate with both
heating and cooling equipment, this control includes an
adjustable differential and an interchangeable
temperature sensor.

As are all System 350™ products, the A350A/B is
housed in a NEMA 1, high-impact plastic enclosure.
The modular design provides easy, plug-together
connections for quick installation and future
expandability.

Figure 1: A350 Series Electronic

Temperature Control

Features and Benefits

Modular Design

Enables stage, display, and power modules to
be purchased and installed as needed

Plug-together Connectors
and 35 mm DIN Rail
Mounting

Eliminates wiring between modules and
reduces installation costs

Two Standard Models
Cover Wide Setpoint
Ranges
-30 to 130°F (-34 to 55°C) or
90 to 250°F (32 to 121°C)

Reduces inventory by encompassing
temperature ranges required to support the
majority of Heating, Ventilation, Air
Conditioning, and Refrigeration (HVAC/R)
applications

Wide Adjustable Differential
of 1 to 30F° (0.6 to 16.7C°)

Enables the user to match equipment cycle
rate and/or sequencing for a given application

Field-Selectable Mode
Jumpers

Operates in both heating and cooling
applications

Available with Either
External or Concealed
Setpoint

Helps deter accidental and unauthorized
adjustments

Interchangeable
Temperature Sensors

Increases versatility and serviceability

System 350™

A350A/B Electronic Temperature Control

Summary of Contents for System 350 A350A

Page 1: ...res and Benefits Modular Design Enables stage display and power modules to be purchased and installed as needed Plug together Connectors and 35 mm DIN Rail Mounting Eliminates wiring between modules and reduces installation costs Two Standard Models Cover Wide Setpoint Ranges 30 to 130 F 34 to 55 C or 90 to 250 F 32 to 121 C Reduces inventory by encompassing temperature ranges required to support ...

Page 2: ...rvisory systems that warn of control failure Setpoint Adjustment Setpoint is defined as the temperature at which the A350A B s relay de energizes Use the Setpoint Dial on the front of the A350A B to adjust setpoint See Figure 2 Differential Adjustment Differential is defined as the change in sensor temperature between energization and de energization of the relay Adjustment of the A350A B differen...

Page 3: ... power and sensor input from the A350 control S350C Slave Stage Modules perform switching functions based upon the A350 s sensor information Setpoint and differential are selected independently at the S350C For more information on these modules refer to the System 350 TM S350C Temperature Slave Stage Module Product Technical Bulletin LIT 930084 S350P Proportional Stage Modules S350P Proportional S...

Page 4: ...into the right side of the A350A B control Note When mounting the System 350 modules to rigid conduit attach the hub to the conduit before securing the hub to the control enclosure WARNING Risk of Electrical Shock Disconnect power supply before wiring connections are made to avoid electrical shock or damage to equipment All wiring must conform to the National Electrical Code and or local regulatio...

Page 5: ...with A350 Series Controls See Tables 3 and 6 The sensor must be connected to the COM and SEN terminals on the four position terminal strip located at the top left of the printed circuit board Refer to Figures 2 4 and 5 The sensors are not polarity sensitive The sensor must be mounted so that it can accurately sense the temperature of the controlled medium Table 3 Sensors Included With A350A B Cont...

Page 6: ... The A350A B setpoint is factory calibrated at midscale to a tolerance of 1F 0 6C Setpoint tolerance at the extreme ends of the setpoint ranges in relation to the printed scale can be 3F 1 7C The D350 Display Module is unaffected by this tolerance shift Use the D350 for the most accurate setpoint selection Checkout Procedure Follow this procedure to verify that the A350A B is connected and functio...

Page 7: ...etpoint Dial Setting Heating On Closed Ts Sp Diff Heating Off Open Ts Sp Cooling On Closed Ts Sp Diff Cooling Off Open Ts Sp Ts is sensed temperature and Sp is setpoint temperature Repairs and Replacement Do not make field repairs or perform calibration Replacement controls and A99B Temperature Sensors are available through the nearest Johnson Controls representative See Tables 5 and 6 for orderin...

Page 8: ...emperature Control Supply Voltage Y350R Power Module Input 120 240 VAC 50 60 Hz Output 24 VDC unfiltered 10 VA Class 2 External Source 24 VAC 50 60 Hz Class 2 20 30 VAC Note Only one supply voltage source may be used Power Consumption 1 4 VA Ambient Temperatures Operating 30 to 150 F 34 to 66 C Shipping 40 to 185 F 40 to 85 C Humidity 0 to 95 RH non condensing maximum dew point 85 F 29 C Setpoint ...

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