5CIM2-0413 W30-AC0056 MODEL AC-SCC-5 INSTALLATION, OPERATION & MAINTENANCE MANUAL Multi-zone Hydronic Chiller Interface Module SECTION 1: INTRODUCTION Unit description... 5 Location... 5 Handling... 5 Mounting pad... 5 SECTION 2: INSTALLATION Mounting... 8 Wiring... 8 SECTION 3: OPERATION Testing... 9 Control logic... 9 Troubleshooting... 9 Electrical diagram... 9 Appendix A: Functionality... 9 Appendix B: Flow diagram... 9 IN UNITED STATES: 260 NORTH ELM ST. WESTFIELD, MA 01085 800-465-8558 / FAX (413) 564-5815 IN CANADA: 7555 TRANMERE DRIVE, MISSISSAUGA, ONTARIO, L5S 1L4 (905) 670-5888 / FAX (905) 670-5782
Section 1: INTRODUCTION The SpacePak AC-SCC-5 is an interface module that allows communication between a wide variety of commercially available thermostats, air handlers, control systems, and the SCM-036 & SCM-060 reverse cycle chillers. The AC- SCC-5 is used to communicate between a group of air handlers (from two to five) and one or more common banked chillers. Description: The AC-SCC-5 consists of an integrated circuit board with relay outputs, multiple connection points for thermostats and air handlers, and a step-down transformer providing 24 VAC, mounted inside metal enclosure that can be located at any indoor location. The AC-SCC-5 received power from a 115V or 230V 60 Hz circuit, and transfers 24VAC signals between the thermostats and air handlers. The output signal to the chiller(s) consists of two dry contacts, one to enable the chiller and one to determine heating or cooling operation. These switch to open or close the low voltage circuit supplied by the chiller Section 2: INSTALLATION Installation: Before beginning, ensure all power is removed from the chiller, either at a breaker or disconnect. Mounting and wiring must be accomplished by a qualifi ed technician who is responsible for compliance with all local codes and good practices. 1. Mount the AC-SCC-5 in a dry indoor location that provides easy wiring access from the air handler, and to the outside chiller. The enclosure must be attached securely to a wall or other fi xed structure. 2. Pass the control wires from the air handlers and thermostats through the grommet at the lower left of the enclosure, and install them as indicated to the terminal strip at the bottom of the panel. 3. Install a minimum four conductor, single strand 22 or 24 AWG copper, thermostat wire from the interface module, to the chiller. 4. Pass the wire through the grommet at the upper right of the enclosure, and connect one each conductor to the four terminal points marked 7 or 11, 8 or 12 & 43, 44 at the top of the panel. Note the color of the individual wires as these must be connected to the same numbered terminals in the chiller. 5. Using the square bit key supplied with the chiller, remove the access plate on the chiller. 6. At the chiller, pass the control/thermostat wire through one of the grommets in the chiller enclosure not already occupied by the chiller power supply wiring. Take care to route the control wire away from the power wire, to avoid the very small possibility that electrical interference could affect the operation of the chiller. 7. Locate the interface terminal strip. Remove the blue jumper (if installed) between connection points 43 and 44. These are for the remote enable signal. Remove them by inserting a 1/8" (3.5 mm) screwdriver blade or other similar tool into the release slot of the connector, and lifting the handle slightly to depress the spring. This will then free the end of the blue jumper which can be gently pulled out of the wire slot. 8. Next, remove the blue jumper (if installed) from the remote Reversing Valve signal. First identify the serial number of the chiller. Refer to the chart below to determine if the chiller is confi guration A or confi guration B. For confi guration A, removed the jumper between terminals 7 & 8, these are the Reversing Valve signal terminals. For confi guration B, removed the jumper between terminals 11 & 12, these are the Reversing Valve signal terminals. 9. While still depressing the spring, install the wires leading from terminals 7/11 & 8/12 of the AC-SCC-5 into the same wire slots. 10. Repeat above steps 8 & 9 at terminals 43 & 44. 11. When all wiring between the thermostats, air handlers, and chiller(s) has been completed, return to the interface panel and connect the power supply. 12. If supplying 115VAC power, connect the Line (hot) wire to the terminal L1 in the interface enclosure, and the Neutral (not ground) wire to the N terminal. Connect the ground wire; bare copper or green, to the Equipment Ground point on the panel. 13. If supplying 230VAC power, connect the L1 (hot) wire to the terminal L1 in the interface enclosure, and the L2 (hot) wire to the L2 terminal. Connect the ground wire; bare copper or green, to the Equipment Ground point on the panel. The neutral terminal will remain empty. 14. Caution! There should never be three wires connected to the L1, N, N2 terminal, one terminal will always remain empty. Never install the ground wire as a neutral, nor the neutral as a ground. 15. Ensure all wire are routed neatly and clear of the access opening, and replace the access panel using the square bit key. 2
Section 2: INSTALLATION (continued) Figure 1 AirCell module mounting Terminals 7 & 8 Terminals 11 & 12 Release Slot Wire Slot Remove jumper, if present Chiller identification AirCell module mounting Chiller Model Serial Number Range Wiring Configuration SCM-036-A4 SCM-060-A4 A1100222680001001 through A1100222680001025 A1100222680001026 and greater A1100222680001001 through A1100222680001035 A1100222680002036 and greater Confi guration A Confi guration B Confi guration A Confi guration B 3
Section 3: OPERATION Testing: 1. When all wire connections have been completed, turn on power to the interface module. The Green, power, LED will illuminate, then either the Red, heat or Blue, cool LED. 2. Set the indoor thermostat, or other control device, to call for heating. (this assumes that the glycol/water solution in the chiller is lower than the heating setpoint. If the temperature is higher, proceed with step 7. 3. Observe that the thermostat, or air handler, sends a signal to call for heating. (Depending on the specifi c thermostat or air handler setpoints, this may pause for of up to two minutes before reacting.) 4. When the call is sent, wire Y1 will energize the left-most relay in the interface module, producing an audible click, and the contacts will close completing the circuit between terminals 43 and 44. 5. The chiller will begin by fl ashing the Pump symbol for one to two minutes while the control undergoes a self-test. The symbol will then become solid and the pump will begin to circulate. The heating symbol will then begin to fl ash, again for one to two minutes, and then become solid. At this time, the compressor(s) will engage and the system will begin heating. 6. Lower the thermostat to remove the call for heating, and allow the chiller to complete its shutdown cycle, running for two to three minutes. 7. When the chiller has shut down and the pump stopped circulating, lower the thermostat to initiate a call for cooling. Again, this may pause for up to two minutes. 8. When the call for cooling is sent, the wire Y1 will again energize the left-most relay, and wire O/B will energize the right-most relay, producing an audible click and opening the circuit between wires 7 and 8. 9. The chiller start sequence will be the same, except that now the cooling symbol will display. Control Logic: The default confi guration, and above description, assume the following. a. The thermostat and/or air handler energizes the O/B connection in cooling, and de-energizes it in heating. b. The chiller operates in cooling when circuit 7 & 8 (or 11 & 12) is open, and heating when circuit 7 & 8 (or 11 & 12) is closed. If either of these conditions is not true, causing the chiller to function opposite to the description above, the operation of the interface module can be reversed by simply relocating wire 7 (or 11), at the right-most relay, from the NC terminal to the NO terminal. Figure 2 Chiller display Heating Symbol Cooling Symbol Pump Symbol 4
Troubleshooting: Condition Possible cause Solution Chiller does not respond to call for conditioning. Chiller operates in cooling when called upon for heating, or heating when called upon for cooling. Power LED illuminates, but not heat or cool LED s, relays chatter or buzz, or no signal to chiller Voltage not supplied to interface module. Time delay has not elapsed Disconnected or broken wire. No power to the chiller Logic is reversed at one component. Improper voltage to circuit board. 24VAC power must be present between the blue and yellow wires of the transformer. Verify that the thermostat or air handler delay has timed out and voltage is being supplied to the interface module. Physically inspect the condition of the wires between the thermostat, air handler and the interface module, and between the interface module and the chiller. Ensure the chiller always has 230VAC power connected, display must remain active at all times. Reverse the logic of the control board. Verify 21 to 27 volts at the transformer output. Ensure power supply is wired according to installation steps 11 or 12. 5
Electrical Diagram 6
Appendix A: Functionality Overview The SpacePak RCB operates up to 5 air handlers with a single chiller or bank of chillers. One specifi c thermostat (i.e. a master) will set the system mode as heating or cooling. Air handlers will each be energized on a call for heating or cooling from their corresponding thermostat only if requesting the same mode as the system. Until the system mode changes, the chiller will remain in the same mode (heating or cooling). The relay control board will also display operational and diagnostic feedback on LEDs. It will have control of whether or not an air handler gets the G signal from their corresponding thermostat. This will allow the fan to run on the air handler when the operating mode permits. Fan only mode will be supported and if a thermostat calls for cooling when the system mode is in heating, the slave will not receive chilled water, and the respective air handler fan will stay on, until the system mode changes to cooling. The thermostat will send a signal to the relay board which will in turn send signals to the chiller, air handler and air handler pump/valve. Individual airhandlers will respond to a fan-only call for air circulation only if the thermostat is capable of supplying this signal. LED Descriptions LEDs on the thermostat side: Green LED Fan input signal coming from thermostat. Yellow LED Y signal coming from thermostat. Red LED OB signal coming from thermostat. LEDs on the Air Handler side: Green LED Fan output signal going to the air handler. Yellow LED Y output signal going to air handler. Air handler is enabled. System mode LEDs: POWER (Green LED) Signifi es that there is power to the board. It is always on if there is power and does not change. COOL (Blue LED) System mode is cooling. If this LED is not held constant (i.e. it is blinking or on with the HEAT LED) it is showing different functionality. HEAT (Red LED) System mode is heating. If this LED is not held constant (i.e. it is blinking or on with the COOL LED) it is showing different functionality. Power Up The SpacePak Relay Control Board will power up when 24VAC is connected to its respective 24VAC terminal block. If for some reason the board needs to be power cycled, disconnect the 24VAC and then reconnect it. On power up the POWER LED will come on and remain on. Either the COOL LED or the HEAT LED will blink three times. If the COOL LED blinks three times then the reversing valve is set to be energized with an O signal. If the HEAT LED blinks three times then the reversing valve is set to be energized with a B signal. After the three blinks occur, the system mode will set to its default mode of heating and the HEAT LED will come on. Auto Rotation Switch OFF Manual Switch AUTO The thermostat connected to the MASTER TSTAT position is designated as the master. This thermostat governs the mode of the entire system. If this master thermostat calls for cooling then the system mode is changed to cooling. If it calls for heating then the system mode is changed to heating. When the master is satisfi ed and is not calling for heating or cooling, the system mode stays in the same mode it was in. For example, if the master was calling for heating and then becomes satisfi ed and stops calling, the system mode stays in heating. When the Master thermostat is calling for either heating or cooling its air handler will be enabled (Yellow LED on). If there is a fan signal present from the master thermostat, it will also be passed on to the air handler (Green LED on). All other thermostats connected to the MEMBER # TSTAT positions are the members. When a member thermostat calls for heating and is in agreement with the system mode (system is in heating), then its air handler will be enabled and fan signal will be passed through. If a member thermostat calls for heating and is not in agreement with the system mode (system is in cooling), then its air handler will be disabled and fan signal will not be passed through. When a member thermostat calls for cooling and is in agreement with the system mode (system is in cooling), then its air handler will be enabled and fan signal will be passed through. If a member thermostat calls for cooling and is not in agreement with the system mode (system is in heating), then its air handler will be disabled and fan signal will still be passed through. As long as there is at least one thermostat calling that is in agreement with the system mode, the chiller will be enabled and its reversing valve will be enabled depending on the system mode. If all thermostats are satisfi ed and there is no call then the chiller will be disabled and there will be no reversing valve signal. If there are only members calling that are not in agreement with the system mode then the chiller will remain disabled and there will be no reversing valve signal present. Manual Switch HEAT The system mode is set to heating and cannot be changed to cooling by any thermostat demand. All functionality mentioned in the Manual Switch AUTO section remains the same except the system mode is always in heating and the master thermostat ( MASTER TSTAT ) now behaves as a member thermostat. Manual Switch COOL The system mode is set to cooling and cannot be changed to heating by any thermostat demand. All functionality mentioned in the Manual Switch AUTO section remains the same except the system mode is always in cooling and the master thermostat ( MASTER TSTAT ) now behaves as a member thermostat. 7
Auto Rotation Switch ON Manual Switch AUTO There is no master thermostat and all thermostats behave in the same way. After all of the thermostats are satisfi ed and not making calls, the fi rst thermostat to reinitiate a call sets the system mode. As long as there is at least one thermostat making a call that is in agreement with the system mode then the system mode cannot be changed. Once all of the thermostats that were in agreement with the system mode are satisfi ed then the system mode can be changed. If there were thermostats making opposite calls simultaneously, the system mode will switch once all thermostats in agreement are satisfi ed. If all thermostats that were making calls that were in agreement are satisfi ed then the system mode will be determined by the fi rst thermostat to reinitiate a call. When a thermostat calls for heating and is in agreement with the system mode (system is in heating), then its air handler will be enabled and fan signal will be passed through. If a thermostat calls for heating and is not in agreement with the system mode (system is in cooling), then its air handler will be disabled and fan signal will not be passed through. When a thermostat calls for cooling and is in agreement with the system mode (system is in cooling), then its air handler will be enabled and fan signal will be passed through. If a thermostat calls for cooling and is not in agreement with the system mode (system is in heating), then its air handler will be disabled and fan signal will still be passed through. As long as there is at least one thermostat calling then the chiller will be enabled and its reversing valve will be enabled depending on the system mode. If all thermostats are satisfi ed and there is no call then the chiller will be disabled and there will be no reversing valve signal. Manual Switch HEAT If there are no calls from any thermostats then the chiller s reversing valve mode changes to be energized when there is a B signal present. The HEAT LED will blink until the manual switch is set back to the AUTO position. While waiting for the switch to go back into the AUTO position, all inputs from the thermostats as well as the Auto Rotation switch will have no effect. However, G signals will still be able to be passed through. After the AUTO position has been selected, the system mode will return to the state it was in before the HEAT position was selected. If there are calls from any thermostats then the reversing valve mode will not change, all air handler outputs will be disabled and the HEAT and COOL LEDs will blink back and forth. This will continue until the manual switch is set back to the AUTO position. While waiting for the switch to go back into the AUTO position, all inputs from the thermostats as well as the Auto Rotation switch will have no effect. After the AUTO position has been selected, the system mode will change to heating. Manual Switch COOL If there are no calls from any thermostats then the chiller s reversing valve mode changes to be energized when there is an O signal present. The COOL LED will blink until the manual switch is set back to the AUTO position. While waiting for the switch to go back into the AUTO position, all inputs from the thermostats as well as the Auto Rotation switch will have no effect. However, G signals will still be able to be passed through. After the AUTO position has been selected, the system mode will return to the state it was in before the COOL position was selected. If there are calls from any thermostats then the reversing valve mode will not change, all air handler outputs will be disabled and the HEAT and COOL LEDs will blink back and forth. This will continue until the manual switch is set back to the AUTO position. While waiting for the switch to go back into the AUTO position, all inputs from the thermostats as well as the Auto Rotation switch will have no effect. After the AUTO position has been selected, the system mode will change to cooling. 8
Appendix B: Flow Diagram SpacePak relay control board flow diagram AirCell module mounting 9
Appendix B: Flow Diagram Master thermostat AirCell module mounting 10
Appendix B: Flow Diagram Slave thermostat AirCell module mounting 11
Appendix B: Flow Diagram Auto rotation AirCell module mounting 12