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Options and unit configurations are indicated in Red and/or brackets [ ] which indicate required choices to be made.

This Engineering Specification is intended for the use of an Engineer when creating an HVAC guide specification that is applicable to a specific project. User should delete any portions of text or descriptions that are not applicable to the specific project. It shall be the responsibility of the Engineer to meet any components or configurations required for applicable building codes, industry standards and system commissioning. Engineer shall coordinate with other product specifications along with any applicable drawings.

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VariCool EZ-Fit

Self-Contained Indoor Floor Mounted

Air Conditioning System

ENGINEERING SPECIFICATION DATA

WATER-COOLED UNITS

Part 1 –General

1.01 Related Documents

A. Drawings and general provisions of the contract, including General and Supplementary Conditions and other Division 1 specification sections, apply to this section.

1.1General Description

A. Furnish and install an indoor self-contained vertical air conditioner system designed to control space temperature and humidity levels. It shall have the performance, electrical characteristics, and air path configurations as defined in the product schedule for the space to be conditioned.

B. The unit(s) shall be a VariCool EZ-Fit modular water-cooled model manufactured by United CoolAir, York, Pennsylvania.

C. The unit(s) shall be installed as asingle packagefloor mounted system.

D. All systems shall be shipped with a full factory refrigerant charge and be ready to wire and pipe once the unit has been placed on site.

E. A wiring diagram shall be affixed to each unit. A printed Installation, Operation and Maintenance Manual shall be provided with each unit. All units shall be suitably labeled for safety purposes and for access.

1.2Quality Assurance

  1. Unit and refrigeration system(s) shall comply with ASHRAE 15, Safety Standard for Mechanical Refrigeration.
  1. Unit shall meet ASHRAE 90.1 Standards for Efficiency.
  2. Unit shall be certified in accordance with UL Standard 1995/CSA C22.2

No. 236-11, safety Standard for Heating and Cooling Equipment.

  1. Unit shall be factory evacuated, charged with refrigerant R-410A, leak tested, and functionally tested as a complete system prior to shipment.
  2. Submittals
  1. Literature shall be provided that indicates unit dimensions, applicable clearances, unit operating weights, capacities, blower performance, filter information, factory supplied options, electrical characteristics, and connection requirements.
  2. Installation, Operation, and Maintenance manual along with start-up procedure shall be provided.
  3. Delivery, Storage, and Handling
  1. Sections shall be shipped with all access panels in place and suitably affixed to prevent damage during transportation and thereafter while in storage either offsite or on the jobsite.
  2. Unit and/or unit modules shall be stored in a clean, dry place protected from construction traffic and the natural elements.
  3. Installing contractor shall follow industry accepted practices and instructions in the Installation, Operation and Maintenance manual for moving unit and/or modulesand for the assembly of modules where required.
  4. Units shall fit through a standard 3-0 doorway without building modifications.
  5. Unit or section of the unit shall not be disassembled in the field, except as designed for, in order to facility placement into the building or mechanical space. Any disassembly of the unit or unit sections not incorporated into the basic design would act to void the unit warranty and reduce the factory quality assurance process.
  6. Warranty
  1. Manufacturer shall provide a “parts only” limited warranty for a period of 12 months from the date of equipment start-up or 18 months from date of shipment from the factory, whichever is less.
  2. Manufacturer shall provide a “compressor parts only” limited warranty for a period of 60 months from the date of equipment start-up or 66 months from date of shipment from the factory, whichever is less.
  3. Manufacturer’s limited warranty shall be for parts only. Labor is not included.

Part 2 – Products

2.01 Cabinet

  1. Cabinet shall be unpainted non-weatherized and constructed of scratch resistant heavy duty galvanized G90 steel.
  1. Cabinet shall be painted non-weatherized construction of scratch resistant heavy duty galvanized G90 steel. All structural members and access panels shall be electrostatically sprayed, powder-coated with a polyester wrinkle finish textured coating designed to function as both a decorative and a protective finish. Film thickness shall be in the range of 2.5 – 4.0 mils and be cured at 375 deg. F. for a minimum of 10 minutes.

Finish shall have a Salt Spray Resistance of 1500+ hours – 1/8” vertical scribe, in accordance with ASTM B117.

Color shall be Rohm & Haas, Corvel 244-0253 Stormy Gray or approved equal.

  1. Cabinet shall be modular in construction, shipped in multiple sections (3-8), on separate skids, depending on unit size in order to facilitate rigging and placement.Factory shall supply suitable devices for assisting in the rigging of the modules for moving and unit assembly.
  2. Cabinet access panels shall fit into recessed pockets within the cabinetstructure and held in place with screws. Recessed areas will be lined with flexiblegasket to minimize air leakage.
  3. Unit shall be provided with removable hinged doors to provide access to variable frequency drive and controls. Hinges shall be fiberglass-reinforced thermoplastic. Access doors shall have tool operated compression latches. Access doors shall be lined with flexible gasket to minimize air leakage.
  4. Intelliclamps shall be provided for reassembly of the unit. The 3-D Intelliclamps will align modular sections for field reassembly allowing a solid connection. Zinc die-cast, black coated with through bolt.
  5. Units are shipped from the factory knocked down into modular section with factory refrigerant charge in the system.
  6. Panels and doors shall allow access to key internal components to facilitateinstallation, maintenance and servicing of the unit.
  7. Inlet and outlet water connections will be located on the [Left] [Right] side of the cabinet independent of electrical connection.
  8. Electrical connection will be located on the [Left] [Right] side of the cabinet independent of water connections.
  9. All duct flanges shall be factory-installed on each unit prior to shipment.
  10. Water piping shall be wrapped in a material that hinders any formation of condensate on the piping.
  11. Insulation shall be 1” mat-faced thermal / acoustic and have an approximate density of 1.9 lbs. / ft3 and a thermal conductivity of 0.13 BTU/ (hr.) (ft2) (°F/in) @ 75° F mean temperature. The insulation shall be dual density fiberglass comprised of a 1.2 lbs. / ft3, flexible core insulation with a 4.0 lbs. / ft3 density, 1/8” fiberglass mat-face. Composite insulation shall be made from fire-resistant, non-corrosive inorganic glass fibers bonded by a thermosetting resin. Insulation shall be installed on the interior top, side and bottom pans, doors and panels. Insulation must meet NFPA 90A and 90B/ASTM-C1071, Type 1 requirements as well as Canadian CGSB 51-GP-11M and CAN 4-s102.
  1. Acoustic Foam Insulation - Cabinet and removabledoors and panels shall be lined with metalized Mylar-faced acoustical foam insulation. Insulation shall meet the requirements of ASTM D3574-86 for Tear Strength, Tensile Strength, Compression Set and Elongation. Insulation shall have chemical resistance tofluids such as moisture, petroleum, solvents, and alkalis. Flammability shall meet MVSS 302, UL-94 HF1 and FAR 25.853(b). Thermal conductivity shall be 0.25 BTU/ (hr.)(Ft2)(Deg. F/in.)
  1. Elastomeric Foam Insulation – Cabinet and removable doors and panels shall be lined with a flexible, closed-cell elastomeric insulation in sheet form. Insulation materials shall have a closed-cell structure to prevent moisture from wicking. Materials shall have a maximum water vapor transmission of 0.08 perm-inches when tested in accordance with ASTM E 96, Procedure A, latest revision. Insulation material shall be manufactured without the use of CFC’s, HFC’s or HCFC’s. Insulation shall be formaldehyde free, low VOC’s, fiber free, dust free and shall resist mold and mildew. Materials shall have a flame spread index of less than 25 and a smoke-developed index of less than 50 when tested in accordance with ASTM E 84, latest revision. Materials shall have a maximum thermal conductivity of 0.27 Btu-in./h-ft2-°F at a 75 °F mean temperature when tested in accordance with ASTM C 177 or ASTM C 158, latest revisions.
  1. Double Wall with Perforated Liner - Cabinet and removabledoors and panels shall be double-wall construction with 1” mat-faced thermal / acoustic insulation and have an approximate density of 1.9 lbs. / ft3 and a thermal conductivity of 0.13 BTU/ (hr.) (ft2) (°F/in) @ 75° F mean temperature. The insulation shall be dual density fiberglass comprised of a 1.2 lbs. / ft3, flexible core insulation with a 4.0 lbs. / ft3 density, 1/8” fiberglass mat-face. Composite insulation shall be made from fire-resistant, non-corrosive inorganic glass fibers bonded by a thermosetting resin. Cabinet interior panels and doors shallbe perforated galvanized metal with 1/8” holes spaced on 3/16” staggered centers.
  1. Double Wall with Solid Liner - Cabinet and removable doors and panels shall be double-wall construction with 1” mat-faced thermal / acoustic insulation and have an approximate density of 1.9 lbs. / ft3 and a thermal conductivity of 0.13 BTU/ (hr.) (ft2) (°F/in) @ 75° F mean temperature. The insulation shall be dual density fiberglass comprised of a 1.2 lbs. / ft3, flexible core insulation with a 4.0 lbs. / ft3 density, 1/8” fiberglass mat-face. Composite insulation shall be made from fire-resistant, non-corrosive inorganic glass fibers bonded by a thermosetting resin. Cabinet interior panels and doors shall be solid galvanized metal.
  2. A representative (direct) from the Manufacturer shall walk the structure with a mockup of the units largest section to ensure accessibility and fit of the entire system without making any modifications to the building structure.

2.02 Refrigerant Circuit

A. Each refrigerant circuit shall be provided with high and low-side Schrader access valves, sight glass with integral moisture indicator, filter-drier, maximum operating pressure (MOP) expansion valve with external equalizer line, manual reset high and auto-reset low pressure safety switches.

B. Each refrigerant circuit will be factory leak tested, evacuated, and charged with R-410A refrigerant prior to shipment. No field piping, brazing, evacuation or refrigerant charging shall be required.

C. Each separate section containing refrigerant circuit components shall be provided with resealable refrigerant fittings in order to preserve the factory refrigerant charge and to facilitate assembly of sections without loss of the refrigerant circuit integrity.

D. Each refrigerant circuit shall be provided with a factory-installed pressure actuated hot gas bypass valve capability that diverts a portion of discharge gas directly into the inlet of the evaporator coil.

  1. Each refrigerant circuit shall include manual shutoff valves on hot gas bypass lines to be used for isolation of the hot gas bypass capability during unit start-up, testing, or maintenance.

2.03 Compressors

  1. Compressors shall be high-efficiency, heavy duty, single-speed, suction-cooled hermetic scroll type, operating at 3450 RPM on 60Hz. The compressor shall contain internal overload protection.
  2. No compressor shall be nominally rated larger than 15 tons.
  3. Compressor shall utilize internal spring vibration isolators and external rubber in shear (RIS) mounting to minimize sound and vibration transmission.
  4. Units with multiple compressors shall have separate independent refrigerant circuits.
  5. Staging of the compressors shall be controlled by the microprocessor based on the supply air temperature.
  6. Variable Speed Compressor – Lead Compressor shall be a hermetically sealed variable speed type. Inverter compressor installed with controls drive.
  7. Digital Scroll Compressor - Lead compressor shall be a hermetically sealed digital scroll type.
  8. Compressor Acoustic Cover - Each compressor shall be provided with a removablecompressor coverusing 1.2-2# density acoustical fiberglass, surrounded by a tough, durable, weather-proof, flame resistant covering.
  9. Compressor Crankcase Heater - Each compressor shall be provided with a wraparound electrical cable resistance heater used to prevent migration and condensation of liquid refrigerant to the compressor crankcase while system is off.

2.04 Evaporator Coil Section

A. The direct expansion evaporator coil shall be configured for draw-thru airflow design for uniform air distribution across the coil face. It shall be made with heavy wall rifled seamless copper tubes mechanically expanded into tempered aluminum fins with corrugated fin design and drawn self-spacing collars. Coil end sheets shall be hot-dipped galvanized.All coils shall be factory leak checked under pressure.

B. Coils shall be interlaced, 4 rows deep with no more than 12 FPI, for uniform performance and optimum part load and humidity operation.

C. The evaporator coil shall utilize a distributor with suitable porting for injection of hot gas bypass. Maximum Operating Pressure (MOP) externally equalized balance port thermostatic expansion valves, externally equalized, shall feed each circuit in the evaporator coil.

D. Evaporator coil section shall be equipped with a 304 stainless steel drain pan. Drain pan shall extend to the entire length and width of the evaporator coil.Units shall have a single1-1/4” NPT condensate drain connection for each module.

E. Evaporator section air path shall be as shown on project drawings.

2.05 Water-Cooled Condensing Section

A. Thewater / glycol condenser coils shall be a co-axial counter-flow refrigerant type. The condensers shall be selected to maintain low refrigerant operating pressure, while using a minimum quantity of water / glycol.Maximum working pressures shall not exceed 450 psig water side, 650 psig refrigerant side.

B. All co-axial heat exchanger water channels shall be fabricated with spiral tubing fabricated out of non-ferrous tubing. Heat exchangers shall incorporate longitudinal fins, spirally-wound and soldered to the inner tube with an outer tube serving as a shell.

C. Each circuit shall provide liquid sub-cooling of the refrigerant.

D. All systems, single or dual module, shall have a single grooved end water supply connection and a single grooved end return connection. Dual module systems internal water interconnecting piping shall be grooved end connections.

E. Each system shall be controlled by a singlewater-regulating valve with a modulating direct-coupled non-spring return actuator. Valve shall regulate fluid flow to control refrigerant head pressure.Valve shall be connected to cooling fluid piping using threaded connections. Valve shall be 2-way pressure-actuated configuration.Valve shall be rated for a 350 psig fluid pressure circuit.

F. Shell and Tube Condenser - The horizontal shell and tube condensers shall have removable heads with mechanically cleanable tubes. Heat exchangers shall be fabricated to meet ASME certified standards. Condensers shall be designed for 150 psig cooling fluid side pressure and 600 psig for the refrigerant side pressure. Condensers shall be constructed of heavy duty steel enclosures with steel tube sheets, steel heads and heavy wall enhanced copper tube geometry. Removable, epoxy coated, heads shall have high quality replaceable gaskets. Shell and tube condensers shall have epoxy coated tube sheets to prevent pitting caused by galvanic action. Tube sheets, water and refrigerant fittings are to be machine welded. Tubes shall be rolled into tube sheets. Each condenser shall be equipped with a SAE flare connection high pressure relief valve. Condensers shall be piped with threaded couplings for easy removal of fluid piping for mechanical cleaning.

2.06A Blower/ Motor Assembly(DWDI – 12 through 25 Ton Single or 24 through 50 Ton Dual)

  1. The blower assembly shall be a belt driven double width double inlet airfoil housed fan. The fan shall incorporate a corrosion resistant steel impeller with 10 (x 2) true airfoil shaped blades which are continuously welded. All wheels are to be coated with an anticorrosive primer and a final layer of epoxy paint. A galvanized spot welded housing and inlet cone shall be utilized. The inlet cones are to be bolted onto the housing side plates.
  2. The impeller and shaft shall be statically and dynamically balanced to an accuracy of G = 2.5 in accordance to DIN ISO 1940-1 and ANSI S2.19-1989. The fan shall comply with the requirements and in accordance with DIN, ISO, BS and AMCA.
  3. The impeller shall be secured to the shaft via an aluminum hub. Hub bore shall be precision machined and incorporate a keyway and locking screw. Shaft shall be designed with the first critical speed well in excess of the maximum fan speed. Shafts shall be fabricated from hardened steel, precision ground and polished and include keyways for the wheel hub and sheaves. The shaft is to have a protective paint added for corrosion protection.
  4. Blower bearings are to be self-aligning, single row, deep groove ball type, in pillow block cast iron housings. Bearings are to have an L50 life time of 200,000 hours (as per AFBMA standards). The pillow block bearings shall be mounted on a flat iron bar, welded to the “T” frame. All bearings shall be complete with re-lubrication fitting factory installed. The operating temperature range shall be from -4° F to +176° F.
  5. The blower V-belt pulley shall be of cast iron construction and keyed to the blower shaft. Motor sheave shall be cast iron, keyed and variable pitch design to allow for field adjustment of specific airflow and static requirements.
  6. The motor shall be an EPACT premium efficiency open drip proof, T-frame having class B insulation, NEMA B design and having a 1.15 service factor. Motor shall have permanently lubricated ball bearings. The motor shall be mounted to an adjustable motor frame.
  7. Belt(s) shall be sized for 200% of motor horsepower.

[Direct Drive Parallel Fans (DDP) 12 through 25 ton single or 24 through 50 ton dual]