Air Cooled Scroll Condensing UnitsME- Building Group

SECTION 236315 – AIR-COOLED SCROLL CONDENSING UNITS

PART 1 - GENERAL

1.1RELATED DOCUMENTS

  1. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification Sections, apply to this Section.

1.2SUMMARY

  1. This Section includes the following:
  2. Air-cooled scroll condensing units.
  3. Related Sections include the following:
  4. Division 23 Section "Instrumentation and Controls for HVAC".
  5. Division 23 Section "Sequence of Operation for HVAC Controls".
  6. Division 23 Section "Refrigerant Piping".
  7. Division 23 Section "DX Air Handling Equipment".

1.3SUBMITTALS

  1. Product Data: Include rated capacities; shipping, installed, and operating weights; dimensions; required clearances; methods for assembling components; furnished specialties; accessories; and installation and startup instructions for each model indicated.
  2. LEED Submittals:
  3. Product Data for Prerequisite EA 2: Documentation indicating that units comply with applicable requirements in ASHRAE/IESNA 90.1
  4. Product Date for Credit EA 4: Documentation indicating that compressor and condenser units and refrigerants comply.
  5. Wiring Diagrams: Detail wiring for power, signal, and control systems and differentiate between manufacturer-installed and field-installed wiring.
  6. Maintenance Data: For each condensing unit to include in the maintenance manuals specified in Division1.
  7. Include a parts list for each condensing unit, control, and accessory; troubleshooting maintenance guide; and servicing and preventive maintenance procedures and schedule.
  8. Warranties: Special warranties specified in this Section.

1.4QUALITY ASSURANCE

  1. Listing and Labeling: Provide electrically operated equipment specified in this Section that is listed and labeled.
  2. The Terms "Listed" and "Labeled": As defined in NFPA70, Article100.
  3. Fabricate and label refrigeration system according to ASHRAE15, "Safety Code for Mechanical Refrigeration."
  4. Comply with NFPA70.
  5. Comply with UL303, "Refrigeration and Air-Conditioning Condensing and Compressor Units."
  6. Factory Test: Condensing Unit shall be pressure-tested, evacuated and given a holding charge of refrigerant and a full oil charge, and shall be factory operational run tested to assure each control device operates properly.
  7. All microprocessor controls shall be compatible with the Building Automation System and shall support LONWORKS and BACNET connectivity.

1.5COORDINATION

  1. Coordinate size and location of structural support bases and roof-mounted piping supports.

1.6DELIVERY AND HANDLING

  1. Deliver unit to job site fully assembled, and given holding charge of refrigerant (HFC-407C) and a full oil charge by the Manufacturer.
  2. Store and handle unit per Manufacturer’s instructions.

1.7WARRANTY

  1. Special Warranty: A written warranty, executed by manufacturer, agreeing to replace components that fail in materials and workmanship within the specified warranty period, provided manufacturer's written instructions for installation, operation, and maintenance have been followed.
  2. A 2-year warranty period, covering parts and labor, shall be valid from the date of Substantial Completion/functional buyoff of the installed units by the manufacturer and the Owner.
  3. Compressor Warranty Period: Manufacturers standard, but not less than 5 years from date of Substantial Completion.

PART 2 - PRODUCTS

2.1MANUFACTURERS

  1. Manufacturers: Subject to compliance with requirements, provide condensing units by one of the following:
  2. Condensing Units, Air Cooled:
  3. Carrier
  4. McQuay
  5. Trane Co. (The)
  6. York International Corp.

2.2CONDENSING UNITS, AIR COOLED

  1. Description: Factory assembled and tested, air cooled; consisting of casing, compressors, condenser coils, condenser fans and motors, and unit controls.
  2. Refer to Division 23 Sections and attached Air Cooled Condensing Unit Schedule for capacities. Match unit to DX cooling coil requirements
  3. Designed for outdoor installation with weather protection for components and controls and with removable panels for required access to compressors, controls, condenser fans, motors, and drives.
  4. Unit Casing: Steel, heavy gauge galvanized or zinc coated, for exposed casing surfaces, coated with baked on powder paint which, when subject to ASTM B117, 500 hour, 5% salt spray test, yields minimum ASTM D1654 rating of “6”.
  5. Lifting lugs to facilitate rigging of units.
  6. Gasketed control panel door.
  7. Vibration Isolation (Field Mounted): 1-Inch Deflection Spring Isolators: Level adjustable, spring and cage type isolators for mounting under the unit base rails.
  8. Provide acoustical sound blankets.
  9. Compressors: Hermetic scroll-type compressor designed for service with crankcase heater, and back-seating service access valves on suction and discharge ports. Include the following:
  10. Tip seals to provide efficient axial sealing while preventing scroll tip to base contact.
  11. Controlled Orbit Design for radial sealing to incorporate minimum flank to flank contact for long service life.
  12. Refrigerant flow through the compressor with 100% suction cooled motor.
  13. Annular discharge check valve and reverse vent assembly to provide low pressure drop, silent shutdown and reverse rotation protection.
  14. Initial Oil charge.
  15. Oil Level sight glass.
  16. Vibration isolator mounts for compressors.
  17. Brazed-type connections for fully hermetic refrigerant circuits.
  18. Condenser: Seamless copper-tube, aluminum-fin coils, with separate and dual independent refrigeration circuits for each compressor. Include liquid accumulator and sub-cooling circuit and back-seating liquid-line service access valves. Factory test coils at 450 psig, then dehydrate by drawing a vacuum and fill with a holding charge of HFC-407C refrigerant. Provide as an option with factory painted fins to increase the heat exchanger life expectancy.
  19. Condenser Fans: Propeller-type vertical discharge. Include the following:
  20. Corrosion resistant glass fiber reinforced composite blades molded into low-noise, full airflow cross section.
  21. Permanently lubricated ball-bearing motors.
  22. Separate motor for each fan.
  23. Separate compartment for each fan to prevent cross-flow during fan cycling.
  24. Fan Motors: High efficiency, direct drive, 6 pole, 3 phase, insulation class “F”, current protected, Totally Enclosed Air-Over (TEAO), rigid mounted, with double sealed, permanently lubricated, ball bearings.
  25. Dynamically and statically balanced fan assemblies.
  26. Heavy gauge PVC coated or galvanized steel fan guards.
  27. Refrigerant Circuit:
  28. Unit piping: Copper, with brazed joints.
  29. Liquid line: Include a field connection shutoff valve with charging port located on each condenser circuit.
  30. Suction line connections: Provide on each refrigeration circuit at the suction valve.
  31. Compressor suction and discharge service valves, replaceable core filter dryer and sight glass.
  32. Connect field refrigerant piping to the condensing unit without loss of charge in the unit.
  33. Individual compressor circuits to be valved off individually.
  34. Controls:
  35. General: Automatic start, stop, operating, and protection sequences across the range of scheduled conditions and transients.
  36. Refer to Specification Division 23 Section "Instrumentation and Controls for HVAC."
  37. Refer to Specification Division 23 Section "Sequence of Operation for HVAC Controls."
  38. Microprocessor Enclosure: Rain and dust tight NEMA 3R/12 (IP55) powder painted steel cabinet with hinged, latched, and gasket sealed door.
  39. Microprocessor Control Center:
  40. Automatic control of compressor start/stop, anti-coincidence and anti-recycle timers, automatic pump-down shut-down, condenser fans, unit alarm contacts, and condensing unit operation from 45Fto 125F ambient. Automatic reset to normal operation after power failure.
  41. Software stored in non-volatile memory, with programmed set-points retained in lithium battery backed real time clock (RTC) memory for minimum 5 years.
  42. Forty character liquid crystal display, descriptions in English, numeric data in English (or Metric) units. Sealed keypad with sections for Set-points, Display/Print, Entry, Unit Options & clock, and On/Off Switch.
  43. Programmable Set-points (within Manufacturer limits): display language; suction pressure setting and control range or remote reset temperature range, set daily schedule/holiday for start/stop, manual override for servicing, low and high ambient cutouts, number of compressors, low suction pressure cutout, high discharge pressure cutout, anti-recycle timer (compressor start cycle time), and anti-coincident timer (delay compressor starts).
  44. Display Data: Outdoor air temperature, English data, suction pressure cutout setting, discharge air reset via the Building Automation System via PWM input as standard or a 4-20 milliamp or 0-10 VDC input or contact closure with optional BAS interface, anti-recycle timer status for each compressor, anti-coincident system start timer condition, compressor run status, no cooling load condition, day, date and time, daily start/stop times, holiday status, automatic or manual system lead/lag control compressor starts/operating hours (each), and fan operation, run permissive status, number of compressors running, liquid solenoid valve status, load & unload timer status.
  45. System Safeties: Shall cause individual compressor systems to perform auto shut down; manual reset required after the third trip in 90 minutes. Includes: high discharge pressure, low suction pressure, high pressure switch, and motor protector. Compressor motor protector shall protect against damage due to high input current or thermal overload of windings.
  46. Unit Safety: Shall be automatic reset and cause compressors to shut down if under voltage.
  47. Alarm Contacts: Low voltage, low battery, and (per compressor circuit): high discharge pressure, and low suction pressure.
  48. Operating and safety controls include the following:
  49. Manual reset, high-pressure cutout switches.
  50. Automatic reset, low-pressure cutout switches.
  51. Low oil pressure cutout switch.
  52. Compressor-winding thermostat cutout switch.
  53. 3-leg, compressor-overload protection.
  54. Automatic, non-recycling pump down and a timing device to prevent excessive compressor cycling.

2.3MOTORS

  1. Motor Construction: NEMAMG1, general purpose, continuous duty, DesignB.

2.4POWER CONNECTION AND DISTRIBUTION

  1. Microprocessor controlled, factory installed Across-the-Line type compressor motor starters.
  2. Power Panels:
  3. NEMA 3R/12 (IP55) rain/dust tight, powder painted steel cabinets with hinged, latched, and gasket sealed outer doors. Provide main power connection(s), control power connections, compressor and fan motor start contactors, current overloads, and factory wiring.
  4. Power supply shall enter unit at a single location, be 3 phase of scheduled voltage, and connect to individual terminal blocks per compressor.
  5. Provide main condensing unit power disconnect switch with fuses or circuit breaker.
  6. Exposed compressor, control and fan motor power wiring shall be routed through liquid tight conduit.
  7. Control Power Transformer: Converts unit power voltage to 120-1-60 (500 VA capacity). Factory mounting includes primary- and secondary-wiring between the transformer and the control panel.
  8. Provide disconnect switch as part of condensing unit assembly.

2.5SOURCE QUALITY CONTROL

  1. Verification of Performance: Rate condensing units according to ARI210/240.

Use paragraph above for units smaller than 135,000 BTUH (39500 W). Use paragraph below for units 135,000 BTUH (39500 W) and larger.

  1. Verification of Performance: Rate condensing units according to ARI340/360.
  2. Coefficient of Performance: Equal to or greater than prescribed by ASHRAE90.1, "Energy Efficient Design of New Buildings except Low-Rise Residential Buildings."
  3. Test and inspect shell and tube condensers according to ASME Boiler and Pressure Vessel Code: SectionVIII, "Pressure Vessels," Division1.
  4. Testing Requirements: Factory test sound-power-level ratings according to ARI270.

PART 3 - EXECUTION

3.1INSTALLATION

  1. Install condensing units according to manufacturer's written instructions.
  2. Install units level and plumb, firmly anchored in locations indicated; maintain manufacturer's recommended clearances.
  3. Install roof-mounted units on air handling unit curb. Anchor unit to supports with removable fasteners.

3.2CONNECTIONS

  1. Connect pre-charged refrigerant tubing to unit's quick-connect fittings. Install tubing so it does not interfere with access to unit. Install furnished accessories.
  2. Connect refrigerant piping to air-cooled condensing units; maintain required access to unit. Install furnished field-mounted accessories.
  3. Ground equipment.
  4. Tighten electrical connectors and terminals according to manufacturer's published torque-tightening values. Where manufacturer's torque values are not indicated, use those specified in UL 486A and UL 486B.

3.3FIELD QUALITY CONTROL

  1. Leak Test: After installation, evacuate connecting piping and charge systems with refrigerant and oil and test for leaks. Repair leaks and replace lost refrigerant and oil.
  2. Operational Test: After electrical circuitry has been energized, start units to confirm proper operation, product capability, and compliance with requirements.
  3. Test and adjust controls and safeties. Replace damaged and malfunctioning controls and equipment.
  4. Remove and replace malfunctioning units with new units and retest.

3.4CLEANING

  1. After completing system installation, including outlet fittings and devices, inspect exposed finish. Clean units to remove dirt and construction debris and repair damaged finishes.

3.5COMMISSIONING

  1. Verify that units are installed and connected according to the Contract Documents.
  2. Complete installation and startup checks according to manufacturer's written instructions and do the following:
  3. Inspect for physical damage to unit casing.
  4. Verify that access doors move freely and are weather tight.
  5. Clean units and inspect for construction debris.
  6. Check that all bolts and screws are tight.
  7. Adjust vibration isolation and flexible connections.
  8. Verify that controls are connected and operational.
  9. Lubricate bearings on fans.
  10. Verify that fan wheel is rotating in the correct direction and is not vibrating or binding.
  11. Start unit according to manufacturer's written instructions.
  12. Complete manufacturer's starting checklist.
  13. Check operation of condenser capacity control device.
  14. Verify that vibration isolation and flexible connections properly dampen vibration transmission to structure.

3.6DEMONSTRATION

  1. Startup Services: Engage a factory-authorized service representative to train Owner's maintenance personnel as specified below:
  2. Train Owner's maintenance personnel on procedures and schedules related to startup and shutdown, troubleshooting, servicing, and preventive maintenance.
  3. Review data in the maintenance manuals.
  4. Refer to Division 23 Section "DX Air Handling Equipment".

END OF SECTION

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Revision Date: 01/21/14 Project & Bid Package

File name: 236316 AIR-COOLED SCROLL CONDENSING UNITS