Installation, Operation, and Maintenance Horizon™ Outdoor Air Unit Indirect Gas-Fired/Electric Heat Models: OA1D, OA2D, OA3D Important: Proper execution of the tasks outlined in this Installation, Operation, and Maintenance manual require and assume the technician has been certified as a start up technician for the Horizon Outdoor Air unit. This includes working knowledge of the Tracer TU program. SAFETY WARNING Only qualified personnel should install and service the equipment.
Introduction Read this manual thoroughly before operating or servicing this unit. Warnings, Cautions, and Notices Safety advisories appear throughout this manual as required. Your personal safety and the proper operation of this machine depend upon the strict observance of these precautions. The three types of advisories are defined as follows: Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
Introduction WARNING Contains Refrigerant! System contains oil and refrigerant under high pressure. Recover refrigerant to relieve pressure before opening the system. See unit nameplate for refrigerant type. Do not use non-approved refrigerants, refrigerant substitutes, or refrigerant additives. Failure to follow proper procedures or the use of nonapproved refrigerants, refrigerant substitutes, or refrigerant additives could result in death or serious injury or equipment damage.
Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Warnings, Cautions, and Notices . . . . . . . . 2 Curb Dimensions . . . . . . . . . . . . . . . . . . . .12 Important Environmental Concerns . . . . . 2 OA2 Units . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Important Responsible Refrigerant Practices ................................... 2 Unit Clearances . . . . . . . . . . . . . . . . . . . . .14 Model Number Descriptions . . . . . . . . . . . . .
Controls Using 24 Vac . . . . . . . . . . . . . . . 30 Controls Using DC Analog Input/Output (Standard Low Voltage Multiconductor Wire) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 DC Conductors . . . . . . . . . . . . . . . . . . . . . . . 31 System Configuration and Pre-Start . . . . . . 33 Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Indirect Gas-Fired Heating Start-Up . . . . . 36 Start-Up Procedure . . . . . . . . . . . . . . . . .
Model Number Descriptions O A 2 D 3 0 0 A 4 1 6 7 2 3 4 5 8 - D 1 A 1 A 0 G M Horizon Outdoor Air Unit Digit 1, 2 — Unit Type OA = Outdoor Air Digit 3 — Cabinet Size 1 2 3 = = = 625 cfm–4,000 cfm 1,500 cfm–9,000 cfm 3,750 cfm–13,500 cfm Digit 4 — Major Design Sequence C D E = = = Revision 4 Revision 5 Heat Pump Digit 5, 6, 7 — Normal Gross Cooling Capacity (MBh) 000 = 060 = 072 = 084 = 096 = 120 = 144 = 180 = 210 = 240 = 264 = 300 = 360 = 420 = 480 = 540 = 600 = 648 = No Cooling 5 Tons
Model Number Descriptions Digit 22 — Heat Capacity (Primary Heat Source) Digit IF ELEC 0 No Heat No Heat A 50 MBh 10 kW B 75 MBh 20 kW C 100 MBh 24 kW D 125 MBh 28 kW E 150 MBh 32 kW F 200 MBh 40 kW G 250 MBh 48 kW H 300 MBh 60 kW J 350 MBh 68 kW K 400 MBh 79 kW L 500 MBh 99 kW M 600 MBh 111 kW N 700 MBh 119 kW P 800 MBh 139 kW R 1000 MBh 179 kW T 199 kW X 00 = AA = AB = AC = AD = AF = AG = AH = AI = AJ = AK = 159 kW S U Digit 25, 26 — Unit Controls
Model Number Descriptions Digit 34 — Filtration Options Digit 38 — Accessories A = B C D E = = = = 0 A B C F = G = H = J = K = L = M N P Q = = = = R = X = Aluminum Mesh Intake Filters (ALM) MERV-8,30%, and ALM MERV-13, 80%, and ALM MERV-14, 95%, and ALM MERV-8 30%, MERV-13 80%, and ALM MERV-8 30%, MERV-14 95%, and ALM MERV-8, 30%, and ALM, with UVC MERV-13, 80%, and ALM, with UVC MERV-14, 95%, and ALM, with UVC MERV-8 30%, MERV-13 80%, ALM, and UVC MERV-8 30%, MERV-14 95%, ALM, and
General Information Overview of Manual Note: One copy of this document ships inside the control panel of each unit and is customer property. It must be retained by the unit’s maintenance personnel. This booklet describes proper installation, operation, and maintenance procedures for air cooled systems. By carefully reviewing the information within this manual and following the instructions, the risk of improper operation and/or component damage will be minimized.
General Information On dual circuit units, if the high pressure control opens, the compressor on the affected circuit is locked out. A manual reset for the affected circuit is required. Space Temperature / RH Sensor (Optional) Field installed, wall mounted temperature sensor (BAYSENS036A) and humidity to control space cooling, heating and dew point. Refer to “Space Control with Indirect Gas-Fired or Electric Heat and Modulating HGRH, ERV, and Powered Ex.,” p. 21 for specific details.
General Information Unit Inspection WARNING Fiberglass Wool! Product may contain fiberglass wool. Disturbing the insulation in this product during installation, maintenance or repair will expose you to airborne particles of glass wool fibers and ceramic fibers known to the state of California to cause cancer through inhalation. Glass wool fibers may also cause respiratory, skin or eye irritation.
Unit Clearances, Curb Dimensions, and Dimensional Data Figure 2. WARNING Combustible Materials! Typical installation clearances for OA1 unit with auxiliary cabinet Maintain proper clearance between the unit heat exchanger, vent surfaces and combustible materials. Refer to unit nameplate and installation instructions for proper clearances. Improper clearances could result in a fire hazard. Failure to maintain proper clearances could result in death or serious injury or property damage.
Unit Clearances, Curb Dimensions, and Dimensional Data Figure 4. Unit curb data for OA1 5–15 tons with auxiliary cabinet Ɍļ 40" Figure 6. Unit dimensional data for OA1 5–15 tons with auxiliary cabinet (in.) 87.33 3 ôļ 12 ɍļ 8 õļ 7 öļ õļ 19" 1 ôļ RE TU 28öļ 1 õļ SU PP öļ 59.23 35.24 RN GUTTER LY 1.00 TYP. GUTTER DETAIL 4 ôļ 49" 131.26 Ɍļ ôļ 53.00 59.45 87.12 Note: Certain options require auxiliary cabinet. Refer to project-specific unit submittals.
Unit Clearances, Curb Dimensions, and Dimensional Data OA2 Units Figure 8. Unit Clearances Typical installation clearances for OA2 unit with auxiliary cabinet CLEARANCE FROM TOP OF UNIT 72" Figure 7. Typical installation clearances for OA2 unit CLEARANCE FROM TOP OF UNIT 72" CLEARANCE 36" CLEARANCE 36" CLEARANCE 48" CLEARANCE 48" CLEARANCE 60" CLEARANCE 60" CLEARANCE 36" CLEARANCE 36" 3'0" 3'0" 4'0" 3'0" 4'0" 3'0" 3'0" 3'0" Note: Certain options require auxiliary cabinet.
Unit Clearances, Curb Dimensions, and Dimensional Data Figure 10. Typical installation clearances for OA2 unit with auxiliary cabinet Dimensional Data Figure 13. Unit dimensional data for OA2 12–30 tons 106.45 43.02 BASE TO BOTTOM OF AIR INLET 6'0" 80.57 7'0" Note: Certain options require auxiliary cabinet. Refer to project-specific unit submittals. Curb Dimensions 106.00 60.00 2 õļ ļ Figure 14. Unit dimensional data for OA2 12–30 tons with auxiliary cabinet 29ļ 9 ôļ 135.52 66.83 94.
Unit Clearances, Curb Dimensions, and Dimensional Data OA3 Units Figure 16. Typical installation clearances for OA3 unit with auxiliary cabinet Unit Clearances CLEARANCE FROM TOP OF UNIT 72" Figure 15. Typical installation clearances for OA3 unit CLEARANCE FROM TOP OF UNIT 72" CLEARANCE 36" CLEARANCE 36" CLEARANCE 48" CLEARANCE 48" CLEARANCE 60" CLEARANCE 60" CLEARANCE 36" CLEARANCE 36" 3'0" 4'0" 3'0" 3'0" 3'0" 4'0" 3'0" 3'0" Note: Certain options require auxiliary cabinet.
Unit Clearances, Curb Dimensions, and Dimensional Data Figure 18. Typical installation clearances for OA3 unit with auxiliary cabinet Dimensional Data Figure 21. Unit dimensional data for OA3 30–54 tons 144.17 6'0" 7'0" 92.07 48.62 Note: Certain options require auxiliary cabinet. Refer to project-specific unit submittals. 42.00 Curb Dimensions 144.00 Figure 19. Unit curb data for OA3 30–54 tons 67.00 74.63 98.49 2 õļ 140ļ 13 ôļ 5 ɏļ RE TU RN Figure 22.
Unit Weight and Rigging WARNING Heavy Objects! Do not use cables (chains or slings) except as shown. Each of the cables (chains or slings) used to lift the unit must be capable of supporting the entire weight of the unit. Lifting cables (chains or slings) may not be of the same length. Adjust as necessary for even unit lift. Other lifting arrangements may cause equipment or property-only damage. Failure to properly lift unit could result in death or serious injury. See details below.
Unit Weight and Rigging Table 2. Typical unit weight and center-of-gravity (CG)—units with auxiliary cabinet Operating Weight (lb) Model Number Shipping Weight (lb) Figure 23. Cabinet corners OAL Cabinet Center-ofgravity (in.
Unit Weight and Rigging Rigging sure that the gasket on the curb is not damaged while positioning the unit. Figure 24. Rigging and center-of-gravity data 4-point lift SPREADER BARS LIFTING POINTS (4 LOCATIONS) WIDTH LENGTH 6-point lift SPREADER BARS LIFTING POINTS (6 LOCATIONS) WIDTH LENGTH DETAIL A SCALE 1 : 12 Refer to Table 1, p. 18, Table 2, p. 19, and Figure 24, p. 20 for typical unit operating weights rigging before proceeding. 1. Remove the shipping crate from around the unit. 2.
Sequence of Operation Space Control with Indirect GasFired or Electric Heat and Modulating HGRH, ERV, and Powered Ex. Sequence of Operation—”Occupied” Optional space temperature and/or humidity sensors must be installed and wired to unit and configured as “installed” at the main unit controller. Emergency Stop. When the contacts at Terminal OAUTS 9 and 10 are open, the unit’s operation will be in Alarm Status. The Alarm must be reset from either the BAS or the optional on-board unit display.
Sequence of Operation Optional Features Digital Compressors Main unit controller will modulate digital compressor to maintain either evaporator leaving or space temperature setpoints depending on mode of operation. Remaining compressors will be staged as described in mode. Starting Sequence with No Return Air Damper Installed. Identical to occupied sequence no return air damper installed. Operating Modes A. Unoccupied Heating B. Unoccupied Dehumidification ERV and Powered Exhaust C.
Sequence of Operation Discharge Air Control with Indirect Gas-Fired or Electric Heat and Modulating HGRH, ERV, and Powered Ex. A. Economizer Mode. Operation in economizer mode is enabled when the outdoor air temperature is between the Outdoor Air Cooling Setpoint and the Outdoor Air Heating setpoint and no call for dehumidification exists. Operation in economizer mode continues until outdoor air conditions call for either dehumidification, cooling or heating mode. Sequence of Operation—”Occupied” B.
Sequence of Operation calls are relocated downstream of the ERV. Mode calls will be based on ERV leaving conditions. Additional sensors will be installed in the non-ERV outdoor air position for information purposes and those outdoor air readings may be viewed at the main unit controller or via the BAS. When operating in economizer mode the ERV is disabled and the ERV by-pass damper(s) open, powered exhaust remains on and is adjusted to 100 percent capacity by the main unit controller.
Installation WARNING Hazardous Service Procedures! Figure 25. The maintenance and troubleshooting procedures recommended in this section of the manual could result in exposure to electrical, mechanical or other potential safety hazards. Always refer to the safety warnings provided throughout this manual concerning these procedures. When possible, disconnect all electrical power including remote disconnect and discharge all energy storing devices such as capacitors before servicing.
Installation Main Electrical Power Requirements Verify that the power supply complies with the unit nameplate specifications. Inspect all control panel components; tighten any loose connections. Connect properly sized and protected power supply wiring to a field-supplied/-installed disconnect switch and to the main power terminal block (HTB1) in the unit control panel. Connect properly-sized earth ground. Figure 26.
Installation ensure that the unit’s supply power wiring is properly sized and installed, refer to the following guidelines. Figure 27. Figure 29. OA2 utility connections Main power entrance MAIN POWER ENTRANCE FOR UNIT 18.95 ELECTRICAL DISCONNECT 13.33 THROUGH BASE ELECTRIC 2.50 Figure 28. OA1D utility connections CONDENSATE DRAIN 1" NPT GAS INLET NPT SIZE VARIES 74.04 9.09 54.49 Table 5. 18.13 23.
Installation Table 6. OA3D Unit MBh Pipe Connection (in.) 300 3/4 350 1 400 1 500 1 600 1-1/4 700 1-1/4 800 1-1/4 1000 1-1/4 Note: All field installed wiring must conform to NEC guidelines as well as State and Local codes. Verify that the power supply available is compatible with the unit’s nameplate ratings. The available supply power must be within 10 percent of the rated voltage stamped on the nameplate. Use only copper conductors to connect the power supply to the unit.
Installation within the proper tolerances, notify the power company to correct this situation before operating the unit. Excessive three phase voltage imbalance between phases will cause motors to overheat and eventually fail. The maximum allowable voltage imbalance is 2.0 percent.
Installation Before initial start up, or if main power has been off for an extended period of time, compressor crankcase heater(s) should be operated for a minimum of 8 hours prior to compressor operation. With main power OFF, remove jumper between OAUTS terminals 9 and 10 (E-Stop). Turn main power to energize crankcase heater(s). At end of warm up period turn main power off, install 9-10 jumper, turn main power on, and resume normal operation.
Installation Controls Using DC Analog Input/Output (Standard Low Voltage Multiconductor Wire) 2. Ensure that the wiring between controls and the unit’s termination point does not exceed 2.5 ohms/ conductor for the length of the run. 3. Do not run the electrical wires transporting DC signals in or around conduit housing high voltage wires. WARNING Hazardous Voltage! Disconnect all electric power, including remote disconnects before servicing.
Installation Figure 32.
System Configuration and Pre-Start The following procedure must be completed prior to performing the start-up procedure in the system Start-Up section in this document. This section describes procedures to navigate the various displays on the Unit Display and configure the Outdoor Air Unit Main Unit Display system setpoints and operating parameters. Important: This section is intended to provide guidelines for navigation through the remote operator display screens.
System Configuration and Pre-Start Table 9.
System Configuration and Pre-Start Table 9. Menu descriptions (continued) Screen Menu System Setpoints Reports (continued from previous page) System Setup Point List Min/Inactive Default Max/Active BAS Point? DAT High Temp Cutout 100°F 125°F 150°F Y DAT Low Temp Cutout 35°F 35°F 50°F Y DAT Temp Cutout Time 10 min. 10 min. 25 min.
Start-Up Indirect Gas-Fired Heating Start-Up WARNING Hazardous Service Procedures! The maintenance and troubleshooting procedures recommended in this section of the manual could result in exposure to electrical, mechanical or other potential safety hazards. Always refer to the safety warnings provided throughout this manual concerning these procedures. When possible, disconnect all electrical power including remote disconnect and discharge all energy storing devices such as capacitors before servicing.
Start-Up 3. Confirm Gas Flow at Unit WARNING Hazardous Voltage and Gas! Turn off the gas supply and disconnect all electric power, including remote disconnects before servicing unit. Follow proper lockout/tagout procedures to ensure the power can not be inadvertently energized and the gas can not be inadvertently turned on. Failure to turn off gas or disconnect power before servicing could result in death or serious injury. Open door to unit vestibule housing the gas heater.
Start-Up • Control can be brought out of lockout by cycling call for heat at the Main Unit Display. Prior to completing the start-up, check the appearance of the main burner flame. Refer to Figure 33, p. 38 for flame characteristics of properly adjusted natural gas systems. Figure 33. Flame characteristics of properly-adjusted natural gas systems • Poor air supply can be caused by obstructions or blockage in heat exchanger tubes or vent discharge pipe. Inspect and clean as necessary to eliminate blockage.
Start-Up Figure 34. OA1/OA2/OA3 indirect gas-fired furnace components IGNITION CONTROLLERS INDUCER BLOWER AIR-PROVING SWITCH INDUCER MOTOR MODULATING GAS VALVE ROLLOUT SWITCH CONDENSATE DRAIN (TYP. 2) ROLLOUT SWITCH HIGH LIMIT SWITCH MANIFOLD GAS PRESSURE TAP FLAME SENSOR MAXIMUM INLET PRESSURE = 14" W.C. MODULATING VALVE INLET PRESSURE TAP MAXIMUM INLET PRESSURE = 14" W.C. ON/OFF GAS VALVE ON/OFF GAS VALVE MANIFOLD GAS PRESSURE TAP Safety Controls Air Pressure Switch.
Maintenance Make sure all personnel are standing clear of the unit before proceeding. The system components will start when the power is applied. • Verify that all damper linkages move freely; lubricate with white grease, if necessary. • Monthly Maintenance Check supply fan motor bearings; repair or replace the motor as necessary. • Before completing the following checks, turn the unit OFF and lock the main power disconnect switch open. Check the fan shaft bearings for wear.
Maintenance Final Process Microchannel (MCHE) Coils NOTICE: Coil Damage! For future reference, you may find it helpful to record the unit data requested below in the blanks provided. (1) Complete Unit Model Number: DO NOT use any detergents with microchannel condenser coils. Use pressurized water or air ONLY, with pressure no greater than 600psi. Failure to do so could result in coil damage. For additional information regarding the proper microchannel coil cleaning procedure, refer to RT-SVB83*-EN.
Performance Data Table 11. OA1 General Data—Cooling 5–8 Tons High Efficiency 5 Tons Downflow 6 Tons Downflow 7 Tons Downflow 8 Tons Downflow OA1D060A OA1D072A OA1D084 OA1D096 61,464 (18.01) 73,757 (21.62) 86,050 (25.22) 98,342 (28.
Performance Data Table 12. OA1 General Data—Cooling 10–15 Tons High Efficiency 10 Tons Downflow 12 Tons Downflow 15 Tons Downflow OA1D120A OA1D144A OA1D144A 121,904 (35.73) 147,514 (43.23) 184,392 (54.04) Cooling Performance Gross Cooling Capacity, Btu (kW) Nominal cfm (m3/h) 1250–2500 (2124–4248) 1500–3000 (2549–5097) 1875–3750 (3186–6371) Compressor Number Type 2 2 2 Scroll Scroll Scroll High Performance Outdoor Coil Type High Performance High Performance Tube Size—OD, in.
Performance Data Table 13. OA2 General Data—Cooling 12–20 Tons High Efficiency 12 Tons Downflow 15 Tons Downflow 17 Tons Downflow 20 Tons Downflow OA2D144A OA2D180A OA2D210A OA2D240A 147,514 (43.23) 184,392 (54.04) 208,973 (61.24) 245,856 (72.
Performance Data Table 14. OA2 General Data—Cooling 22–30 Tons High Efficiency 22 Tons Downflow 25 Tons Downflow 30 Tons Downflow OA2D264A OA2D300A OA2D360A Gross Cooling Capacity, Btu (kW) 270,442 (79.26) 307,320 (90.07) 368,784 (108.08) (m3/h) 2750–5500 (4692–9345) 3125–6250 (5309–10619) 3750–7500 (6371–12743) Cooling Performance Nominal cfm Compressor Number Type 2 2 2 Scroll Scroll Scroll High Performance Outdoor Coil Type High Performance High Performance Tube Size—OD, in.
Performance Data Table 15. OA3 General Data—Cooling 30–40 Tons High Efficiency 30 Tons Downflow 35 Tons Downflow 40 Tons Downflow OA3D360A OA3D420A OA3D480A Gross Cooling Capacity, Btu (kW) 368,784 (108.08) 430,248 (126.09) 491,712 (144.11) (m3/h) 3750–7500 (6371–12743) 4375–8750 (7433–14866) 5000–10000 (8495–16990) Cooling Performance Nominal cfm Compressor Number Type 2 3 3 Scroll Scroll Scroll High Performance Outdoor Coil Type High Performance High Performance Tube Size—OD, in.
Performance Data Table 16. OA3 General Data—Cooling 45–54 Tons High Efficiency 45 Tons Downflow 50 Tons Downflow 54 Tons Downflow OA3D540A OA3D600A OA3D648A Gross Cooling Capacity, Btu (kW) 553,176 (162.12) 614,640 (180.13) 663,811 (194.
Performance Data Superheat and Refrigeration Circuit Data Figure 36. Refrigeration diagram: Single compressor with reheat Figure 35.
Performance Data Figure 37. Refrigeration diagram: dual compressor no reheat OAU-SVX01E-EN Figure 38.
Performance Data Figure 39. Refrigeration diagram: triple compressor with no reheat 50 Figure 40.
Performance Data Figure 41. Refrigeration diagram: quad compressor with no reheat OAU-SVX01E-EN Figure 42.
Alarms and Troubleshooting Microprocessor Control System Alarms The Main Unit Display and RTRM have the ability to provide the service personnel with some unit diagnostics and system status information. The Main Unit Display has built in alarms to help the operator troubleshoot system failures. This section will describe these alarms and provide a guide to troubleshooting the all unit operating modes.
Alarms and Troubleshooting Table 17. TOAU UC600 alarms (continued) Point Diagnostic 11 Space Temp Source Failure Possible Cause Table 18.
Alarms and Troubleshooting RTRM Failure Modes WARNING Live Electrical Components! During installation, testing, servicing and troubleshooting of this product, it may be necessary to work with live electrical components. Have a qualified licensed electrician or other individual who has been properly trained in handling live electrical components perform these tasks. Failure to follow all electrical safety precautions when exposed to live electrical components could result in death or serious injury.
Appendix OAU Filter Guide Table 21. OA3D Units Evaporator Table 19. OA1D Units Evaporator Thickness MERV 2 in. 8, 13 4 in. 14 Thickness MERV Qty Height 2 in. 8, 13 9 24 Width 20 4 in. 14 9 24 20 Qty Height Width 2 16 20 2 16 25 Return Air 2 16 20 Thickness MERV Qty Height Width 2 16 25 2 in. 8 6 18 20 Thickness MERV Qty Height Width 2 in.
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