ETM-2050/ETM-2051 Service Manual

Introduction Novar s Electronic Thermostat Modules (ETMs) are intelligent control modules that provide local, direct digital control of unitary, packaged, staged HVAC systems. This document: Describes the ETM-2050 and ETM-2051. Lists precautions that must be observed by those servicing the modules. Provides wiring schematics Explains how to troubleshoot the modules Explains how to replace the ETM Explains how various sensors work with the ETM It also provides the following troubleshooting charts: Communications loss WTS-UVC Open/Shorted Faults RTS-UVC Open/Shorted Faults Rooftop Unit Response Precautions TE! To perform any of the operations outlined in this manual, a person must meet both of the following qualifications: Be a licensed electrician or a licensed HVAC technician. Have experience in troubleshooting building automation and HVAC controls. WARNING! Some service and maintenance checks in this manual require that the unit s power be turned on. Multiple voltages at the rooftop unit present an electrical shock hazard that can cause injury or death. Before attempting to service the Novar Controls equipment, turn off power to the rooftop unit at the disconnect switches. When performing the service checks that require power, turn on the power as necessary but be aware that the electrical shock hazard exists. No one should perform the operations outlined in this manual unless he or she meets the qualifications specified above and is trained and experienced in working with the following voltages: 24-VDC 24-VAC DOC. #TD-0270 2/1/07 1

110-VAC 208-VAC 277-VAC 480-VAC 560 VAC Wiring Schematics The ETM-2050 (Figure 1) and ETM-2051 are designed to be mounted by Lennox at its factory and powered by the rooftop unit. TRANSFORMER COMMUNICATION STATUS LIGHT JUMPER TABS, TYP. ON ETM LOAD BLOCK LOAD STATUS LIGHTS, TYP. ETM FUSE Figure 1. ETM-2050 with baseplate Lennox also mounts the following sensors at the factory: Remote Temperature Sensor (RTS-UVC) in the supply-air duct (monitoring point only) Remote Temperature Sensor (RTS-UVC) in the return-air duct (to be used as a control sensor) 2 DOC. #TD-0270 2/1/07

Table 1 lists sensors that can be mounted in the field for use with the ETMs. Table 1. Field-Mountable Sensors ETM-2050 ETM-2051 WTS-UVC RTS-UVC FTS-3 FTS-3A WTS-UVC RTS-UVC WTS-SOS FTS-3 FTS-3A TE! On an ETM-2050 or an ETM-2051, a Wall-Mounted Temperature Sensor (WTS-UVC) or an RTS-UVC can be used as a control sensor. If a WTS-UVC is used to achieve proper control, the RTS-UVC must be unplugged (J62/P62; refer to the wiring schematic, Figure 2). On an ETM-2051, a switch-over Wall-Mounted Temperature Sensor (WTS-SOS) can also be used. If the WTS-SOS is used, the RTS-UVC should not be unplugged. Refer to the ETM-2051 wiring schematic (Figure 3) and its key for more information. Jack 62 3 A2 4 A2 Figure 2. ETM-2050 wiring schematic DOC. #TD-0270 2/1/07 3

Table 2. ETM-2050 Wiring Schematic Key A1 Control Module, Novar s ETM P62 Plug, A2, Return-Air Sensor A2 Sensor (see Notes 3 & 4) P63 Plug, RT1, Discharge-Air Sensor A16 Communication Loop from Executive Module P64 Plug, S27, Filter Switch J3 Jack, Economizer P65 Plug, S50, Fan Switch J16 Jack, Unit P79 Plug, Header, Novar J17 Jack, Logic Panel P80 Plug, Novar Pigtail J39 Jack, Adapter, Novar R18 Pot, Remote Setpoint J62 Jack, A2, Return-Air Sensor RT1 Sensor, Discharge J63 Jack, RT1, Discharge-Air Sensor S27 Switch, Filter J64 Jack, S27, Filter Switch S52 Switch, Airflow J65 Jack, S50, Fan Switch S56 Switch, MOM, After Hours J66 Jack, Novar s ETM TB1 Terminal Strip, Low Voltage J79 Jack, Novar s Pigtail 1 J3 Maximum Load 20vA, 24-VAC, Class 2 J80 Header Pigtail 2 Alternate Location P17 Plug, Logic Panel 3 Sensor, Return-Air TE! Shows the factory-mounted return-air sensor at Plug 62, Jack 62. Disconnect if zone temperature sensor is used. P18 Plug, Unit 4 Sensor, Room Air TE! Shows connection for field-mounted zone temperature sensor. When using this sensor, unplug the factory-mounted return-air sensor at Plug 62, Jack 62. P39 Plug, Adapter, Novar 5 J17, P80 Harness may or may not be used. 4 DOC. #TD-0270 2/1/07

Dashed lines indicate field-installed cables A74 FTS-3A A2 VAR RETURN-AIR SENSOR RT1 VAR DISCHARGE-AIR SENSOR WTS-SOS FTS-3 ALTERNATE RTS-UVC ALTERNATE Figure 3. ETM-2051 wiring schematic DOC. #TD-0270 2/1/07 5

Table 3. ETM-2051 Wiring Schematic Key A1 Panel Logic P62 Plug: A2 RA Sensor A2 Sensor: Return-Air (Novar) P63 Plug: RT1 DA Sensor A16 Communication Loop from Executive Module P64 Plug: S27 Filter Switch A17 Detector: Smoke P65 Plug: S50 Fan Switch A42 Monitor: Phase Protection P66 Plug: Cool-1 A55 Panel: Main P79 Plug: Header, Novar A56 Panel: Economizer P99 Plug: Discharge Temp Sensor A63 Sensor: CO 2 (IAQ) Optional P100 Plug: Return Temp Sensor A64 Detector: Smoke, Supply-Air P101 Plug: Smoke Detector, Return-Air A74 Sensor: Room (64K61) P102 Plug: Smoke Detector, Supply-Air A75 Sensor: Room (95H5301) P103 Plug: Sensors, Control A95 Sensor: Averaging P110 Plug: Thermostat Input A98 Sensor: Temp Switch-Over P112 Plug: Cooling Sensor Input J16 Jack: Unit P113 Plug: Blower & Cool-1 Control J62 Jack: A2 Return-Air Sensor P114 Plug: Sensor Input J63 Jack: RT1 Discharge-Air Sensor P115 Plug: Economizer Output J64 Jack: S27 Filter Switch P125 Plug: Blower Proving J65 Jack: S52 Fan Switch P126 Plug: Jumper, Blower Proving J66 Jack: Cool-1 Interface P142 Plug: Economizer Harness J79 Jack: Pigtail to P17 RT1 Sensor: Discharge J80 Jack: Header RT6 Sensor: A55 Discharge (IMC) J99 Jack: Discharge Temp Sensor RT16 Sensor: Return-Air Temp J100 Jack: Return Temp Sensor RT17 Sensor: Outside-Air Temp J101 Jack: Smoke Detector, Return-Air S27 Switch: Filter J102 Jack: Smoke Detector, Supply-Air S42 Overload: Relay, Blower Motor J103 Jack: Sensors, Control S52 Switch: Airflow J110 Jack: Thermostat Input S56 Switch: Momentary Override J112 Jack: Cooling Sensor Input TB1 Terminal Strip 24-V Class 2 J113 Jack: Blower & Cool-1 Control 1 TB1-19 is service relay output (24-VAC). If used, connect to an indicator light or relay coil (max 4VA). continued 6 DOC. #TD-0270 2/1/07

J114 Jack: Sensor Input 2 For motors with S42 external overload and with A55 (IMC) software version 1.07 and newer. J115 Jack: Economizer Output 3 Disconnect A2, return-air sensor, Plug 62, from unit jack, J62, when A74 or A75 room sensor is used. J125 Jack: Blower Proving 4 A95 averaging sensor may be used with A74 or A75 room sensors. Disconnect RT1 discharge-air sensor (Novar) when A95 is used. J126 Jack: Jumper, Blower Proving 5 Alternate A74 room sensor, used in place of A75. J142 Jack: Economizer Harness 6 J99/P99, J100/P100, and J103/P103 are not used on 036, 042, 048, 060, 072, 088, and 100 units. P16 Plug: Unit 7 A2 return-air sensor remains in place when A98 switch-over sensor WTS-SOS (18L36010 IS USED. P17 Plug: Logic Panel 8 TB1-20 for dehumidification control. The TB1 terminal strip (Figure 4) provides connections for the following items. Table 4. ETM-2050/ETM-2051 Terminal Connections 2, 3, and 8 Communications (negative, shield, and positive, respectively) 5 and 9 WTS power (negative and positive, respectively 2.5-VDC 0.55-VDC A If the sensor is not connected or polarity is reversed, voltage is 5 VDC. TE! No connections should be wired to Terminals 5 and 11 or 6 and 7. These should be used for troubleshooting purposes only. Terminals 5 (negative) and 11 (positive) can be used to check for 0.55-VDC voltage for the RTS. Terminals 6 and 7 can be used to verify 24-VAC power. DOC. #TD-0270 2/1/07 7

TE! The ETM is a Class 2, low voltage device. Do not connect 115 volts to any terminal. The outputs are controlled by low-voltage triacs. Do not exceed 24-VAC at 1 amp. The WTS and communication wires are terminated on the TB1 terminal strip. Do not attempt to jump out RTU loads at the TB1 terminal strip. Use the jumper tabs on the ETM load block. SOS Sensor Temp (if used) COMMUNICATIONS ( ) COMMUNICATIONS SHIELD WTS/RTS ( ) COMMON ETM POWER SOS Sensor Shield (if used) ETM POWER COMMON COMMUNICATIONS ( + ) WTS ( + ) Zone or Novar (A2) Sensor RTS ( + ) Discharge (RT1) Metering Point SOS Sensor (+) (If used) Timed Override Figure 4. TB1 terminal strip 8 DOC. #TD-0270 2/1/07

Troubleshooting the ETM-2050/ETM-2051 CAUTION! If the unit is being converted back to conventional thermostatic control, the Com Bus must be removed from TB1 Terminals 2, 3, and 8. WARNING! Before performing any of the operations outlined on the following pages, review the Note and the Warning that appear on the inside of the cover of this manual. Anyone performing service on an ETM should locate and check the following items before beginning any troubleshooting procedures: ETM communication status light-emitting diode (LED) located on the left side of the module (see Figure 1) ETM load status lights (see Figure 1) ETM address switches located near the top of the module, next to the address switch label (see Figure 1) Rooftop unit (RTU) communicating with the ETM The communication status light indicates if the module is currently receiving electrical power and its current mode of operation. The following table explains the light s operation. Table 5. ETM Communication Status Light Operation IF THE COMMUNICATION STATUS LIGHT Is completely off Blinks off approximately every 5 to 15 seconds Blinks on every 15 seconds for 3 minutes before switching to normal mode Blinks on approximately every 15 seconds Blinks off 3 times approximately every 15 seconds Blinks on and off steadily EXPLANATION The ETM has no power. The ETM is operating in normal/occupied mode. The ETM is going through its initial power up. The ETM is in unoccupied mode. The ETM address is incorrect. The ETM has power but is not communicating. DOC. #TD-0270 2/1/07 9

The ETM s address switches must be set accurately for it to communicate with the appropriate rooftop unit and executive module. Typical ETM addresses coincide with the RTU number, as shown in Figure 5. TE! Address settings above 63 are shown in parentheses in Figure 5. (64) (65) (66) (67) (68) (69) (70) (71) (72) (73) (74) (75) (76) (77) (78) (79) (80) (81) (82) (83) (84) (85) (86) (87) (88) (89) (90) (91) (92) (93) (94) (95) (96) (97) (98) (99) (100) (101) (102) (103) (104) (105) (106) (107) (108) (109) (110) (111) (112) (113) (114) (115) (116) (117) (118) (119) (120) (121) (122) (123) (124) (125) (126) (127) Figure 5. ETM address settings The following charts can be used to troubleshoot communications loss. 10 DOC. #TD-0270 2/1/07

Communications Loss Troubleshooting Chart 1 Checking the ETM for Power Does the rooftop unit (RTU) have power? Is the communication status light on the ETM on (i.e., is it receiving power)? Refer to Table 5 in this document for an explanation of the light s operation. Use standard HVAC troubleshooting procedures. The communications loss is not related to the energy management system (EMS). Move to Communications Loss Troubleshooting Chart 2. Do TB1 Terminals 6 and 7 have 24-VAC power? Power is being delivered to the ETM. Is the ETM fuse good? Use standard HVAC troubleshooting procedures. Power is not being delivered to the ETM. Check the control transformer, fuse, smoke detector, etc. Replace the ETM with an identical module using the procedures provided in this document and make sure the replacement operates correctly. Replace the fuse with a 1-amp fuse, make sure the status light begins to blink, and verify that communication has been restored. DOC. #TD-0270 2/1/07 11

Communications Loss Troubleshooting Chart 2 Checking the Wires, Terminals, and Address Is the communication status light on? Remove the wires from TB1 Terminals 2, 3, and 8. Separate the wiring if wired as a daisy chain loop. Take meter readings between TB1 Terminals 2 and 3, between 8 and 3, between positive and shield on the wires, and between negative and shield on the wires. Is 2.5-VDC present on both sets of wires and the terminals? Move to Communications Loss Troubleshooting Chart 1. Is the ETM s address correctly set (see Figure 5)? Is 2.5-VDC present on the wires but not on the terminals? Replace the ETM with an identical module (using the procedure Re-address the ETM, reinstall it, and verify that communication Take meter readings on Pins 2 and 3 and 8 and 3 at P80. provided in this manual) has been restored. and verify that Is 2.5-VDC present? communication has been restored. Is 2.5-VDC present on the terminals but not on the wires? If so, communication was lost before reaching this unit. Check connections at any junction box on the communication loop. Check communication voltage at nearby units. Check connections at P16 and P17. Replace the ETM with an identical module (using the procedure provided in this manual) and verify that communication has been restored. 12 DOC. #TD-0270 2/1/07

Replacing the ETM Use the procedure provided below to replace an ETM. TE! Novar s ETM-2050 model is being replaced with Novar s ETM-2051 model. A standard phone handset cord (Novar Part No. 770009000) is needed (not supplied) to monitor IMC faults. Step Procedure 1 Turn off the rooftop unit at the disconnect. 2 Unplug J79, P80, and the Y1 stake-on connector. 3 Remove the four screws used to mount the ETM (Figure 6). 4 Set the address switches on the replacement ETM to match the address setting on the original ETM. Refer to Figure 5, as necessary. 5 Align the replacement ETM over the mounting holes, insert the mounting screws, and tighten to secure the module. 6 (Optional: Applies to ETM-2051 only) Plug a standard phone handset cord (Novar Part No. 770009000) into the IMC connection on the ETM-2051 (Figure 6) for IMC fault monitoring. 7 Plug in J79, P80, and the Y1 stake-on connector and turn on the rooftop unit at the disconnect. 8 Wait 3 minutes, then check the status light to make sure it is blinking. 9 Verify that communication has been restored. Contact any Novar Technology Center (NTC) or Novar account representative to obtain instructions for returning the defective ETM. DOC. #TD-0270 2/1/07 13

MOUNTING HOLES DIP SWITCHES ADDRESS EACH UNIT TO EXECUTIVE MODULE BLINKING STATUS LED INDICATES RMAL OPERATION IMC LED AND BUS CONNECTOR FUSE M O U N TING H O L E REMOVE FUSE AND JUMPER TERMINALS TO ACTIVATE INDIVIDUAL OUTPUTS MANUALLY M O U N TING H O L E Figure 6. ETM-2051 with IMC connection 14 DOC. #TD-0270 2/1/07

+ ETM-2050/ETM-2051 Service Manual Wall-Mount Temperature Sensor (WTS-UVC) Novar s Wall Temperature Sensor (WTS-UVC; Figure 7) can be used with the ETM-2050 and ETM-2051. RED BLACK HORIZ BLACK - RED Figure 7. WTS-UVC The sensor is mounted in the zone controlled by each RTU and uses a shielded two-wire cable to: Receive power from the ETM: 0.55 VDC with the sensor attached 5 VDC with the sensor unattached or polarity reversed TE! Polarity must be observed when the sensor is wired. Send the ETM a DC voltage signal proportional to the zone temperature. The ETM translates the signal into a 40 to 150 F reading as shown in Table 6. Table 6. WTS-UVC Signal Translation APPROXIMATE VOLTAGE APPROXIMATE TEMPERATURE (IN DEGREES FAHRENHEIT) 0.591 50 0.582 57 0.557 77 0.535 95 0.510 115 0.465 150 The sensor is permanently calibrated at the factory. The following chart should be used to troubleshoot WTS-UVC faults. DOC. #TD-0270 2/1/07 15

WTS-UVC Open/Shorted Faults Troubleshooting Chart Determine if there is a shorted fault or an open fault. SHORTED FAULT OPEN FAULT Are P62 and J62 (typically located in the filter access area of the RTU) plugged in? Unplug P62 and J62 and verify reading. Visually inspect the sensor. Is the sensor damaged? Replace the sensor with an identical model and make sure the replacement operates properly. Remove the sensor s cover to check the wiring connections. Are any of the connections loose? IF 0.55 VDC IS PRESENT Reconnect any loose wires. Make sure the sensor is functioning properly. IF 5 VDC IS PRESENT Take meter readings at the + to terminals with the wires connected to determine what voltage is present. IF VOLTAGE IS PRESENT Replace the ETM with an identical model, using the procedure provided in this document and make sure it operates properly. Reverse polarity and take a meter reading. Is 0.55 VDC present? Remove the wires from the sensor and meter the wires. Is 5-VDC present? If the reading is still open/short, replace the sensor with an identical model and verify the reading. Verify that the reading is correct. Replace the sensor with an identical one and verify the reading. The sensor is shorted. Replace the sensor with an identical one and verify the reading. Take a meter reading at Terminals 5 and 9 on the TB1 terminal strip located inside the RTU. Is 5 VDC present? The sensor wire is open. Trace and repair it. Remove the wires and remeter Terminals 5 and 9 on the TB1 terminal strip. Is 5 VDC present? The sensor wire is open. Trace and repair it. Take a meter reading at Pins 5 and 9 at the P80 plug (plugged into the ETM). Is 5 VDC present? Pins 5 and 9 in Plugs P16 and J17 are open. Make sure the pins are properly seated and verify the reading. Replace the ETM with an identical model, using the procedure provided in this document. Make sure it operates correctly. 16 DOC. #TD-0270 2/1/07

Remote Temperature Sensor Novar s supply-air Remote Temperature Sensor (RTS-UVC; Figure 8) uses a two-wire cable to: Receive DC voltage from the ETM. 0.55 VDC with the sensor attached 5 VDC with the sensor unattached or polarity reversed TE! Polarity must be observed when the sensor is wired. Send the ETM a DC voltage signal proportional to the supply-air temperature. The ETM translates that signal into a 40 150 F reading as shown in Table 7. Figure 8. RTS-UVC Table 7. RTS-UVC Signal Translation APPROXIMATE VOLTAGE APPROXIMATE TEMPERATURE (IN DEGREES FAHRENHEIT) 0.591 50 0.582 57 0.557 77 0.535 95 0.510 115 0.465 150 The sensor is permanently calibrated at the factory. TE! The return-air sensor must be unplugged for proper control if a wall temperature sensor is used. Use the following troubleshooting chart and refer to Table 7, as necessary, to troubleshoot Remote Temperature Sensor faults. DOC. #TD-0270 2/1/07 17

RTS-UVC Open/Shorted Faults Troubleshooting Chart Take a meter reading on Pins 1 and 3 at the J63 plug on the ETM located inside the RTU to determine what voltage is present If 0.55 VDC IS PRESENT If 5 VDC IS PRESENT If VOLTAGE IS PRESENT Replace the ETM with an identical model and check the reading. If the reading is still open/shorted, replace the Remote Temperature Sensor and verify the reading. Replace the Remote Temperature Sensor with an identical model, verify polarity, and verify the reading. Take a meter reading at Pins 5 and 11 at the J79 plug (which is plugged into the ETM. Is 5 VDC present? Make sure that Pins 5 and 11 in Plug P17 and J16 or Pins 5 and 11 in Plugs P39 and J3 are properly seated and verify the reading. Replace the ETM with an identical model. Make sure the replacement functions properly. Rooftop Unit Does Not Respond to ETM Calls Troubleshooting Chart If the rooftop unit (RTU) does not respond to calls from the ETM, find out which load the ETM should be calling and check the status lights on the ETM in the RTU. Do the status lights coincide? Remove the fuse, place a jumper across the jumper tabs on the ETM load block to force a call for heat, cool, or fan. Does the RTU respond? Is the ETM addressed correctly for the RTU (refer to Figure 5)? Replace the ETM with an identical model using the procedure provided in this document and make sure that it operates correctly. Use standard HVAC troubleshooting procedures. The cause is not related to the energy management system (EMS). Replace the ETM with an identical model using the procedure provided in this document and make sure that it operates correctly. Set the ETM s address switches for the correct address and make sure that the RTU responds. 18 DOC. #TD-0270 2/1/07

Wall-Mount Temperature Switch-Over Sensor (WTS-SOS) Novar s Wall-Mount Temperature Switch-Over Sensor (WTS-SOS) should be mounted in the space being controlled to provide a fall-back mode of operation for controlling the zone temperature. The fall-back mode is programmed in Novar s software to switch control to the return-air sensor if the signal is lost from the WTS-SOS. A two-conductor shielded cable (Belden 8761, Novar WIR-1010, or equivalent) should be used to make the wiring connections indicated in the following procedure. Step Procedure 1 Connect a wire from the sensor terminal marked Temp to Terminal 1 on the module. 2 Connect a wire from the sensor terminal marked + to Terminal 12 on the module. 3 Connect the shield wire from the terminal marked Shld to Terminal 5 on the module. The material in this manual is for information purposes only. The contents and the product it describes are subject to change without notice. Novar makes no representations or warranties with respect to this manual. In no event shall Novar be liable for technical or editorial omissions or mistakes in this manual, nor shall it be liable for any damages, direct or incidental, arising out of or related to the use of this manual. No part of this manual may be reproduced in any form or by any means without prior written permission from Novar. Copyright 2006 by Novar. All Rights Reserved. Printed in the U.S.A. Novar; 6060 Rockside Woods Blvd., Cleveland, OH 44131 Tel.: 800.348.1235 www.novar.com DOC. #TD-0270 2/1/07 19

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