FANs 216, 1628.3 Product/Technical Bulletin SEN-500-2, SEN-500-3 Issue Date 0996 SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors The SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors offer economical solutions to outdoor air temperature measurement in applications with the T500 Series of programmable and non-programmable thermostats. The sensors consist of either a duct mount sensor (SEN-500-3) or an outdoor air sensor (SEN-500-2) and a communication module that provides a digital interface between the sensor and a T500 thermostat. Figure 1: Outdoor Air Temperature Communication Module and Sensors Features and Benefits Single Assembly Ordering Application Diversity Digital Communication Interface Simplifies ordering; provides complete assembly (including communication module, sensor, and all hardware) in one box T500 thermostat can be located up to 300 feet from the communication module, and the sensor can be located up to 500 feet from the communication module Eliminates wire resistance variability associated with 2-wire passive sensors 1996 Johnson Controls, Inc. 1 Part No. 24-4034-131, Rev. A Code No. LIT-216179
O utdoor Air Sensors Overview SEN-500-2 for outdoor air mounting includes: 3 in. 10K thermistor sensor outdoor air shield conduit enclosure with cover wire nuts (2) remote communication module screws and anchors (2) 4.46 113.3 3.47 88.1 1.38 35.0 6.0 max. 152.4 2.54 64 3.50 89 0.81 21 Figure 4: Communication Module Dimensions (in./mm) 0.67 17.0 45 Figure 2: Outdoor Air Sensor Dimensions (in.\mm) SEN-500-3 for duct mounting includes: 8 in. 10K thermistor sensor quick mount sensor holder and retainer metal mounting plate with screws (4) and locknut conduit enclosure with cover wire nuts (2) remote communication module screws and anchors (2) 2.75 69.9 7.5 max. 190.5 Location Considerations Avoid areas subject to excessive vibration or electrical noise. Mount the sensor in an area where it will not be influenced by air currents, radiated heat, or conducted heat. Air currents and heat could adversely affect the temperature at the sensor. Do not exceed the temperature range given in the Specifications table. 6.0 max. 152.4 Plate Dimensions: 3 in. x 3 in. (76 mm x 76 mm) 1.72 43.7 Figure 3: Duct Mount Sensor Dimensions (in./mm) 2 SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin
Communication Module and Sensor Installation! WARNING: Shock Hazard. Disconnect power supply before wiring connections are made to prevent electrical shock or possible damage to the equipment. Prior to installing the communication module, install the T500 thermostat following the instructions provided with the unit. Note: The maximum wiring run between the thermostat and communication module is 300 feet (91.5 m), and the maximum wiring run between communication modules is 300 feet (91.5 m). The maximum wiring run between the outdoor air communication module and its sensor is 500 feet (152.4 m). Install the communication module and sensor as follows: IMPORTANT: When using shielded wire to ensure proper communications, the total distributed capacitance of the wire run between the T500 thermostat and the communication module must not exceed 15 nf. 1. Install 3-wire 18 AWG cable from the T500 thermostat to the outdoor air communication module location. Unshielded wire is normally recommended. Shielded cable, Belden number 8770 or equivalent, is recommended for applications in electrically noisy environments. Tape the shield at the communication module and terminate the shield at the 24V(c) terminal of the T500 thermostat. 2. Install the outdoor air sensor and 2-wire 18 AWG cable from the sensor location to the outdoor air communication module location. Unshielded wire is recommended on wiring runs less than 20 feet (6.1 m). Shielded cable, Belden number 8760 or equivalent, is recommended for wiring runs longer than 20 feet (6.1 m). Tape the shield at the sensor and terminate the shield at Terminal 2 of the communication module. 3. Using a 3/8 in. (9.5 mm) screwdriver, open the communication module by pushing the cover latch located on the bottom of the module case. (See Figure 5.) 4. Carefully remove the circuit board from the communication module by disengaging the tab that holds the circuit board in place. (See Figure 6.) 5. Using the base as a template, mark the location of the two mounting holes. Drill two 3/16 in. (5 mm) holes at the marked locations, and tap nylon anchors flush to wall surface. Pull the wire cables through the opening in the base and fasten the base to the wall using the supplied screws. (See Figure 7.) 6. Connect the 3-wire cable wires between Terminals RS1, RS+V, and RS2 on the T500 thermostat and communication module. Connect the sensor wires to Terminals 1 and 2 on the communication module. See Figures 8 and 9. 7. Snap the circuit board back into place and replace the cover on the communication module. 8. Press the Outdoor button on the T500 thermostat to verify that the sensor is functioning. Cover Latch Press with screwdriver to open. Figure 5: Opening the Communication Module SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin 3
To Sensor 0.38 9.5 To Thermostat 2.54 64 0.38 9.5 0.70 18 AVG RS2 RS+V RS1 2 1 Circuit Board Tab 0.65 17 2.45 62 Figure 6: Removing the Circuit Board Figure 8: Outdoor Sensor/Communication Module Wiring Diagram (in./mm) Note: The maximum wiring run between the thermostat and communication module is 300 feet (91.5 m), and the maximum wiring run between communication modules is 300 feet (91.5 m). The maximum wiring run between the outdoor air communication module and its sensor is 500 feet (152.4 m). T500 Thermostat RS1 RS+V RS2 1 2 SEN-500-1 Indoor Sensor 1 (optional) RS1 RS+V RS2 AVG Figure 7: Mounting the Communication Module Base 1 2 RS1 SEN-500-1 Indoor Sensor 2 (optional) RS+V RS2 AVG Outdoor Sensor Wiring If an SEN-500-1 is used for remote indoor sensing, or if a series of SEN-500-1 sensors are used for averaging, the outdoor air communication module can be wired with the remote indoor sensor(s) as shown in Figure 9. Wire the sensor to the outdoor air communication module as shown in Figures 8 and 9. 1 2 RS1 RS+V RS2 AVG SEN-500-2 or 3 ODA Communication Module Outdoor Air or Duct Temperature Sensor Figure 9: Outdoor Sensor/Communication Module Wiring Schematic 4 SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin
Sensor Installation Step 1: Drill a 1-3/8 in. (35 mm) diameter hole at the desired mounting plate location. Using the mounting plate as a template, drill four 1/8 in. (3 mm) holes for the screws. Sensor Holder Step 2: Mount probe assembly to duct. Retainer Step 3: Insert wires and sensor holder into conduitbox. Ensure that the sensor holder snaps in place. Slide theretainer inside sensor holder. Step 4: Attach conduit box to conduit. Step 5: Wire the sensor to Terminals 1 and 2 of the communications module. Step 6: Close conduit box cover and firmly tighten screws. Figure 10: Duct Mount Sensor Step 3: Close conduit box cover and firmly tighten screws. Step 2: Connect the sensor wires to the wires connected to Terminals 1 and 2 of the communication module using wire nuts provided. Note: The outdoor air sensor may be secured to a flat surface by drilling screws through the back of the conduit box. Step 1: Secure conduit box to conduit and pull wires from the communication module to the conduit box. Figure 11: Outdoor Air Sensor SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin 5
Troubleshooting Table 1: Troubleshooting Symptom Possible Cause Corrective Action Thermostat has no outdoor air temperature display... Temperature displayed at the T500 does not correlate with temperature at the outdoor air sensor... Incorrect wiring. Outdoor air sensor or communication module are not correctly connected. T500, communication module, or outdoor air sensor failure. Incorrect voltage. Communication module failure. Check wiring between outdoor air sensor, communication module, and thermostat. Check wiring connections at thermostat terminal blocks, between thermostat and communication module, and between communication module and outdoor air sensor. Short the sensor by jumpering Terminals 1 and 2 at the communication module. Reading at the T500 thermostat should read the maximum. If the reading at the T500 thermostat does not read the maximum, check the communication module. If the reading at the T500 does read the maximum, measure the resistance of the sensor with the wires removed from the terminals of the communications module. The resistance should be 10,000 ohm at 77 F. If resistance is not correct, replace the sensor. Measure the voltage across Terminals RS2 and RS+V. Voltage should be 20 to 30 VAC. If the voltage is not within this range, check and correct the voltage at the T500. Note: The voltage reading across Terminals RS2 and RS+V should be the same as the voltage reading across Terminals 24V and 24C of the T500. Measure the voltage across Terminals RS2 and RS1. Voltage should be a pulsed 18 to 20 VDC signal. If the voltage is not within this range, replace the communications module. Ordering Table 2: Ordering Information Item Outdoor Air Temperature Communication Module with Outdoor Air Sensor Outdoor Air Temperature Communication Module with Duct Mount Sensor Product Code Number SEN-500-2 SEN-500-3 6 SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin
Replacement and Repair Parts The SEN-500 Series of products allows for easy replacement of the sensor. For a replacement sensor, contact the nearest Johnson Controls Table 3: Replacement Parts Item representative and order using the information from the Replacement Parts and Repair Parts tables. Product Code Number Replacement Outdoor Air Temperature Communication Module Replacement Outdoor Air Temperature Sensor (including mounting hardware) Replacement Duct Mount Temperature Sensor (including mounting hardware) Table 4: Repair Parts Item SEN-500-603 SEN-500-604 SEN-500-605 Product Code Number 3 in. Sensor Probe (use with outdoor air sensor) SEN-500-601 8 in. Sensor Probe (use with duct mount sensor) SEN-500-602 SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin 7
Specifications Product Power Requirements Sensor Temperature Coefficient Reference Resistance Sensor Accuracy Communication Module Ambient Operating Conditions Communication Module Ambient Storage Conditions Sensor Ambient Storage and Operating Conditions T500 Temperature Display Range when Used with the SEN-500-2 or SEN-500-3 SEN-500-2 Outdoor Air Temperature Communication Module with Outdoor Air Sensor SEN-500-3 Outdoor Air Temperature Communication Module with Duct Mount Sensor Supplied by T500 Thermostat Nonlinear, Negative Temperature Coefficient 10K ohm at 77 F (25 C) ±4 F from -4 to 86 F; ±2 C from -20 to 30 C 32 to 122 F (0 to 50 C); 5 to 90% RH noncondensing -30 to 122 F (-34 to 50 C) Sensor Probe: Conduit Box: -55 to 118 F (-48 to 48 C) -50 to 220 F (-46 to 104 C) -50 to 122 F (-46 to 50 C) Sensor Construction Sensor: 1/4 in. O.D. Stainless Steel Probe Conduit Access Box: Rigid PVC Plastic Sensor Holder: Gray LEXAN Sensor Lead Wires Communication Module Dimensions (H x W x D) 22 Gauge Wire 2.54 x 0.81 x 3.50 in. (64 x 21 x 89 mm) Shipping Weight SEN-500-2: 0.5 lb (0.23 kg), Includes Outdoor Air Temperature Sensor and Outdoor Air Communication Module SEN-500-3: 0.4 lb (0.19 kg), Includes Duct Mount Sensor and Outdoor Air Communication Module The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these specifications, consult the local Johnson Controls office. Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products. Controls Group 507 E. Michigan Street P.O. Box 43 Milwaukee, WI 53201 M3643 Printed in U.S.A. 8 SEN-500-2 and SEN-500-3 Outdoor Air Temperature Sensors Product/Technical Bulletin