® We manage heat ® Model GPT–3 Freeze Protection Thermostat Part Number 19425 Installation and Operation Manual Environmental Technology, Inc. 1850 N Sheridan Street South Bend, Indiana 46628 (574) 233-1202 or (800) 234-4239 FAX (574) 233-2152 or (888) 234-4238 http://www.networketi.
DISCLAIMER Environmental Technology, Inc. makes no representations or warranties, either expressed or implied, with respect to the contents of this publication or the products that it describes, and specifically disclaims any implied warranties of merchantability or fitness for any particular purpose. Environmental Technology, Inc.
Table of Contents Safety Contacting Environmental Technology General Introduction Specifications Operation Normal Abnormal Installation First Next Location Supply and Heater Connections Sensor and Alarm Relay Connections General Temperature Sensors Alarm Relay Contacts Setup Factory Settings Custom Settings General GFEP Mode Current Constant Wattage Heater Mode Maintenance General Troubleshooting Returns 7 7 7 7 9 10 10 10 10 10 10 11 11 12 12 12 14 14 14 15 15 15 15 16 16 17 17 17 17 Page 3 of 21
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Index of Figures Figure 1. GPT–3 dimensional drawing Figure 2. GPT–3 wiring diagram Figure 3. Control and monitor sensor connections for self-limiting heaters Figure 4. Control sensor connection for constant wattage heaters Figure 5. Alarm relay connections Figure 6. DIP switch detail Figure 7. Removing electronic assembly from housing Appendix A. GPT–3 dimensional drawing. Appendix B. GPT–3 wiring diagram. Appendix C. Control and monitor sensor connections for self-limiting heaters. Appendix D.
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Safety Make all electrical connections in compliance with the National Electric Code (NFPA 70) and local electrical code. If you have questions concerning the installation or application, contact Customer Service. Contacting Environmental Technology For assistance, contact Customer Service. Office hours are 8:00 AM until 5:00 PM EST (UTC minus five hours). Voice: (800) 234.4239 (USA and Canada) or (574) 233.1202 (elsewhere) Fax: (888) 234.4238 (USA and Canada) or (574) 233.
the control sensor temperature, the GPT–3 may momentarily declare a cold heater. The GPT–3 automatically executes a self-test every 24 hours. First, heaters are deenergized. Then, the GFEP verifies its own operation. Finally, it checks the heaters for ground fault under operating conditions. This entire process takes about two seconds. Other features include verifying the integrity of both the control and monitor temperature sensors and checking the contactor for open or shorted contacts.
Specifications Control Range: 41° to 77°F (5° to 25°C) Dead band: 2°F (1°C) Electrical Supply: 120, 208, 240 or 277 volts auto-selected Heater load: 30 amps maximum Alarm relay: Isolated SPDT 1 amp Class 2 contact Indicators Supply (red) Power applied Heater (yellow) Call for heat GFEP (red) Ground fault occurring or has occurred FAULT (red) Contactor failure Temperature sensor failure Power-on self-check failure GFEP Settings: 30 mA default, 60, 90, 120 mA selectable Reset: Manual defau
Operation Normal The GPT–3 requires little or no attention after installation. Although changing the temperature setting can improve heating system performance, this is seldom necessary. Minimum energy use occurs when the the temperature is set to the minimum value providing the desired heating performance. Normal operation occurs when neither the Fault nor the GFEP indicators operate and the Alarm relay is off. Otherwise, operation is abnormal.
Location The GPT–3 is suitable for indoor or outdoor mounting on a vertical surface. Although the NEMA 3R rated housing is strong and durable, choose a protected location for an extra safety margin. Always consider the possibilities of tampering and vandalism when choosing a location. Keep the GPT–3 and the heat cable as close together as is practical to minimize installation costs. There is a 2,000’ (610m) limit on temperature sensor extension wiring. Figure 1 shows mechanical dimensions of the GPT–3.
wire size of 10 AWG with, minimum, 300 volt insulation rated for at least 75ºC. Figure 2 shows a pictorial wiring diagram of the heater and supply voltage connections. Use appropriately rated wire nuts or bomb splices for all heater and supply connections. Connect the equipment safety ground and heater shield ground to the lug provided for this purpose.
J1 GPT –3 TRACON ® Low Voltage Compartment ® GFEP FAULT SUPPLY HEATER FAULT HEATER 59 15 RESET 50 10 20 68 GFEP TEST 41 5 °C °F 25 77 Temperature ® We Manage Heat ® http://www.networketi.com e-mail: helpdesk@networketi.com Control Temperature Sensor Figure 4. Control sensor connection for constant wattage heaters J1 GPT –3 TRACON ® ® GFEP FAULT SUPPLY HEATER FAULT HEATER 59 15 RESET 50 10 20 68 GFEP TEST 41 5 °C °F 25 77 Temperature ® We Manage Heat ® http://www.
connection of the two sensors. The GPT–3 comes factory set for self-limiting cable. Systems using constant-wattage heaters require only one sensor as is shown in Figure 4. Upon completion of the installation, dispose of the unused sensor. Alarm Relay Contacts Figure 5 shows the alarm relay connections. The relay contacts are rated for one amp in NEC Class 2 service. Contact Customer Service if higher voltage operation is required. Setup Factory Settings The GPT–3 comes set for the most common systems.
J1 GPT –3 TRACON ® ® GFEP FAULT SUPPLY HEATER FAULT HEATER 59 15 RESET 50 10 20 68 GFEP TEST 41 5 °C °F 25 77 Temperature ® We Manage Heat ® http://www.networketi.com e-mail: helpdesk@networketi.com Figure 7. Removing electronic assembly from housing Custom Settings General The performance of the GPT–3 can be adjusted to match the needs of the application using the DIP switch as shown in Figure 6.
Current The GFEP current setting can be increased from its factory set 30 mA value to 120 mA in 30 mA steps. The higher current settings serve the special purpose of eliminating spurious GFEP tripping. Accessing this function was made intentionally difficult to prevent its casual use.
Maintenance General The GPT–3 does not require routine maintenance. It contains no field replaceable components. Troubleshooting The GPT–3 provides extensive fault diagnosis capability for the purpose of quickly identifying and correcting system problems. Front panel indicators perform multiple functions so as to provide the greatest amount of information.
Page 18 of 21 Grounding Lug (21mm) Conduit Entry 3/ " 4 CL J1 CL 12" (305mm) 11 1/2" (292mm) 21/8" (54mm) 2" (51mm) 4" (102mm) High Voltage Compartment Low Voltage Compartment (21mm) Conduit Entry 3/ " 4 GFEP TEST 50 5 °C °F 20 25 77 ® 68 We Manage Heat ® Temperature 41 10 http://www.networketi.com e-mail: helpdesk@networketi.
To Heater 30 Amp Load Max. Heater Shield Ground Equipment Safety Ground Line/L1 Neutral/L2 Ground From 120, 208, 240, or 277 VAC Supply J1 GFEP TEST 50 5 °C °F 20 25 77 ® 68 We Manage Heat ® Temperature 41 10 http://www.networketi.com e-mail: helpdesk@networketi.com RESET HEATER HEATER FAULT 59 15 SUPPLY ® GFEP FAULT ® GPT –3 TRACON Appendix B. GPT–3 wiring diagram.
Monitor Temperature Sensor Control Temperature Sensor Low Voltage Compartment J1 Page 20 of 21 GFEP TEST 50 5 °C °F 20 25 77 ® 68 We Manage Heat ® Temperature 41 10 http://www.networketi.com e-mail: helpdesk@networketi.com RESET HEATER HEATER FAULT 59 15 SUPPLY ® GFEP FAULT ® GPT –3 TRACON Appendix C. Control and monitor sensor connections for selflimiting heaters.
Control Temperature Sensor Low Voltage Compartment J1 GFEP TEST 50 5 °C °F 20 25 77 ® 68 We Manage Heat ® Temperature 41 10 http://www.networketi.com e-mail: helpdesk@networketi.com RESET HEATER HEATER FAULT 59 15 SUPPLY ® GFEP FAULT ® GPT –3 TRACON Appendix D.
