GUIDE SPECIFICATION SECTION238146-1
Revised 16 February 2016Water Source Heat Pump Units
SECTION 238146 –WATER SOURCE HEAT PUMP UNITS
PART 1 GENERAL
RELATED DOCUMENTS
Contractors, manufacturers, manufacturer representatives, vendors, suppliers, etc. are cautioned that requirements of the Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 1 Specification sections, apply to work of this section. Sections 230210, 230220, 230240, 230510, 230511, 230533, 230593, 230596, and 230924, must be reviewed for compliance with the requirements of this section.
//ENSURE THAT EACH OF THE FOLLOWING SPECIFICATION SECTIONS ARE INCLUDED AS PART OF THE PROJECT SPECIFICATIONS.//
Unit components shall meet the specific requirements of the following Specification sections:
Component / SectionElectrical service / 230511
Motors / 230513
Drives / 230210/230514
Fans / 233416
Coils / 238216
Support/Vibration Control / 230529/230548/233313
Filters / 234113/234123/234133/234213
AHU Section / 237311/237313
Refrigeration Section / 236219
QUALITY ASSURANCE
Comply with the following Air-Conditioning, Heating, and Refrigeration Institute (AHRI) standards, as applicable:
210/240, Performance Rating of Unitary Air-Conditioning and Air-Source Heat Pump Equipment
340/360, Performance Rating of Commercial and Industrial Unitary Air-Conditioning and Heat Pump Equipment
520, Performance Rating of Positive Displacement Condensing Units
575, Method of Measuring Machinery Sound Within an Equipment Space
Units with nominal total cooling capacity of 135,000 Btuh or less shall comply with AHRI/ISO-13256-1 and be listed in the current AHRI Applied Equipment Directory.
Comply with the following Air Movement and Control Association (AMCA) standards, as applicable:
210, Laboratory Methods of Testing Fans for Aerodynamic Performance Rating
410, Recommended Safety Practices for Users and Installers of Industrial and Commercial Fans
Comply with American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 15, Safety Standard for Refrigeration Systems
Comply with National Fire Protection Association (NFPA) Standard 90A, Standard for the Installation of Air-Conditioning and Ventilating Systems
Building Code Compliance: Packaged units shall meet or exceed the minimum efficiency rating required by the InternationalEnergy Conservation Code.
Extended Warranty: The Contractor shall provide an extended parts and labor warranty on each refrigeration compressor in addition to guarantees and warranties required under the General Conditions to the Construction Contract.
The parts portion of the warranty shall be directly from the manufacturer to the Owner.
The labor portion of the warranty shall also be provided directly from the manufacturer to the Owner.
Exception: Where a manufacturer labor warranty is not available, the Contractor shall provide a labor warranty directly to the Owner.
This warranty shall provide for repair or replacement of the covered compressor, including removal and/or replacement of refrigerant, that becomes inoperative as a result of defects in materials or workmanship within 4 years after the date ending the initial 1-year guarantee period for the Project.
SUBMITTALS
General: Submittals shall demonstrate compliance with technical requirements by reference to each subsection of this specification. Where a submitted item does not comply fully with each and every requirement of the Specifications, the submittal shall clearly indicate such deviations. Identification requirements for non-complying features of items are very specific. See Section 230210 for exact requirements.
Manufacturer's Data: Submit manufacturer's technical product data, including rated capacities of selected model clearly indicated, weights, furnished specialties and accessories, and installation and startup instructions.
PART 2 PRODUCTS
DESCRIPTION
Packaged horizontal or vertical direct expansion refrigeration air-to-water/water-to-air ("water source") heat pumps consisting of casing, fan(s), indoor air heating/cooling coil, refrigeration system with compressor(s) and refrigerant-to-water heat exchanger, and microprocessor-based unit controls, as indicated on the Drawings. Heat pumps shall be fabricated with flanges for both supply and return ductwork connection.
Heat pumps shall be connected to a water source that serves as their heat sink/source, as follows:
//SELECT ONE OF THE FOLLOWING THREE SYSTEM DESCRIPTIONS AS REQUIRED FOR THE PROJECT.//
Closed-Loop System: The system consists of multiple units connected to a 2-pipe, closed-loop hydronic system with variable flow water circulation. The temperature of the water loop shall be maintained at approximately 60-95 degrees F by means of addition of heat and heat rejection when needed.
Ground Source Closed-Loop System: The system consists of multiple units connected to a 2-pipe, closed-loop hydronic system with continuous water circulation. The temperature of the water loop shall be maintained between approximately 30-120 degrees F by means of heat addition or heat rejection into the ground loop.
Ground Source Open-Loop System: The system consists of multiple units connected to a 2-pipe, open-loop hydronic system with continuous water circulation. The temperature of the water loop shall be operating over an extended range, 30-120 degrees F, by means of heat addition or heat rejection directly into the ground water.
AIR-HANDLING SECTION
//SMALLER HEAT PUMPS, LESS THAN 3-4,000 CFM AIRFLOW, MAY BE CONSTRUCTED IN TO COMPLY WITH SECTION 237311, WHILE LARGER UNITS MUST MEET THE REQUIREMENTS OF SECTION 237313. EDIT THE FOLLOWING SENTENCE ACCORDINGLY.//
Air-handling section and components shall comply with Section 237311 or 237313, as indicated on the Drawings and/or hereinbefore specified:
Supply and return fans shall be DWDI forward-curved blade type complying with Section 233416.
Refrigerant cooling and hot gas reheat coils and electric, hot water, or steam heating coils, as required, shall comply with Section 238216.
Hot-Water Preheat Coil: For units with 40% or more outdoor ventilation air requirements, provide hot water heating coil in compliance with Section 238216 with two-way modulating control valve and manual air vent, utilizing loop water supply/return as indicated on the Drawings.
//SELECT OPTIONAL WATERSIDE ECONOMIZER COIL IF REQUIRED FOR THE APPLICATION.//
Waterside Economizer Coil: Where indicated on the Drawings, provide waterside economizer coil in compliance with Section 238216 with two-way modulating control valve and manual air vent, utilizing loop water supply/return as indicated on the Drawings.
//THE FOLLOWING PARAGRAPH IS REQUIRED FOR PROJECTS LOCATED IN COUNTIES ADJACENT TO THE OCEAN.//
Coating for Coastal Environments: Air coils exposed to greater than 40% outdoor air flow at any time shall be factory coated to prevent salt air corrosion of aluminum fins. Coating shall be epoxy or phenolic epoxy type rated for minimum 4000 hours salt spray resistance when tested in accordance with ASTM B 117 and minimum 4000 hours humidity resistance when tested in accordance with ASTM D 2247, applied at least 1.2 mils thick.
If unit is indicated on the Drawings to be equipped for airside economizer cycle operation, outside air, return air, and relief air dampers shall comply with Section 233313 and shall be sized by the manufacturer in accordance with in accordance with ASHRAE Guideline 16, Selecting Outdoor, Return, and Relief Dampers for Air-Side Economizer Systems.
REFRIGERATION SECTION
Refrigeration system and components shall comply with the requirements of Section 236219, except as follows:
//SELECT THE WATER-TO-REFRIGERANT HEAT EXCHANGER REQUIRED FROM THE FOLLOWING TWO PARAGRAPHS. TYPICALLY, SELECT CUPRONICKEL FOR CLOSED LOOP SYSTEMS AND STAINLESS STEEL FOR GROUND LOOP SYSTEMS.//
Refrigerant/Water Heat Exchanger: Provide coaxial, tube-in-tube heat exchanger with cupronickel water tube with enhanced heat transfer surfaces inside a stainless steel outer tube. Heat exchanger shall be leak tested to 450 psig on refrigerant side and 400 psig on water side. Factory mount heat exchanger on resilient rubber vibration isolators. Provide water regulating valve to limit water flow through the heat exchanger to control compressor(s) head pressure. Valve shall close to stop flow through the heat exchanger when the compressor is not energized.
Refrigerant/Water Heat Exchanger: Provide brazed-plate heat exchanger fabricated of Type 316 stainless steel. Factory mount heat exchanger in unit on resilient rubber vibration isolators and leak test to 450 psig for refrigerant side and 400 psig or water side. Factory mount heat exchanger on resilient rubber vibration isolators. Provide water regulating valve to limit water flow through the heat exchanger to control compressor(s) head pressure. Valve shall close to stop flow through the heat exchanger when the compressor is not energized.
Humidity Control:
Provide hot-gas bypass refrigerant control incorporating constant pressure expansion valve and solenoid valve to maintain continuous refrigeration system operation down to 10% of full capacity of (lead) compressor.
Provide first-stage condenser consisting of hot-gas reheat coil located downstream of cooling coil.
Hot-gas bypass and hot-gas reheat valves shall be replaceable coil, pilot-operated sliding type.
Insulation: Insulate cold surfaces, including unit casings, drain pan, etc., to prevent condensation with ambient humidity of 75 percent and drybulb temperature of 90 deg.F, no air movement, in accordance with Section 230716.
LOOP WATER CONNECTIONS
Connect supply and return hydronic piping to heat pump as detailed on the drawings via flexible hose kits. Hose diameter shall match unit connection size. Provide isolation valves, inlet Y-type strainer, and balancing valve for each unit, complying with Section 232113.
Hoses shall be equipped with swivel end NPS threaded connections permanently crimped or welded to meet required pressure ratings. Hoses shall be stainless steel braid over a fire retardant EPDM liner bonded to the braid or stainless steel braid over corrugated Type 321 stainless steel tube. Hoses shall be rated for minimum working pressure of 400+ PSI at 0 to +200°F.
Hose length shall be sufficient to allow above-ceiling units to be dropped below the ceiling level before disconnecting hoses or 36 inches, whichever is greater.
UNIT CONTROLS
Manufacturer-furnished, factory-installed unit controls, including final control elements, shall meet the requirements of Section 230913, Section 230923, and the control I/O points and sequences shown on the Drawings. Unit controls shall interface seamlessly with the DDC system specified in Sections 230913 and 230923, fully complying with the operational requirements for “Control Units” specified in Section 230923:
Coordination: The Contractor shall be responsible for coordination between the controls system sub-contractor and the unit controller manufacturer/vendor to ensure that required control interface is implemented, resulting in full interoperability between unit controls and the DDC system. The unit controller shall include input/output points required to enable the sequence of operation indicated on the drawings.
ELECTRICAL CONNECTION
Provide single-point power connection, factory-wired to the power connection lug set. Electrical connection work shall be in accordance with Section 230511.
PART 3 EXECUTION
INSTALLATION OF UNITS
Install units in accordance with manufacturer's installation instructions.
Install units plumb and level, firmly anchored in locations indicated, and maintain manufacturer's recommended clearances.
Base-mounted units shall be installed on housekeeping pads in accordance with Section 230210.
Suspended units shall be installed with all thread hanger rods and structural attachments in accordance with Section 230529.
Install units with auxiliary drain pan extending 3" beyond unit casing in each direction. Drain pan shall be constructed of minimum 20 gauge galvanized steel, minimum 1-1/2" deep, with hemmed edges.
FIELD QUALITY CONTROL
Perform inspections, start-up procedures, and field tests in compliance with manufacturer's written instructions, specifically incorporating the following:
Inspect for visible damage to unit casing.
Inspect for visible damage to compressor, coils, and fans.
Inspect internal insulation.
Verify that labels are clearly visible.
Verify that clearances have been provided for servicing.
Verify that controls are connected and operable.
Verify that filters are installed.
Adjust vibration isolators.
Verify bearing lubrication on fan.
Inspect fan-wheel rotation for movement in correct direction without vibration and binding.
Start unit according to manufacturer's written instructions.
Inspect and record performance of interlocks and protective devices; verify sequences.
Inspect controls for correct sequencing of heating, mixing dampers, refrigeration, and normal and emergency shutdown.
Operate unit for an initial period as recommended or required by manufacturer and test for performance compliance after the installation is complete and electrical circuitry is energized. Remove and replace malfunctioning units and retest.
Submit report of inspections and start-up tests to A/E and include a copy in the O&M manual.
OWNER INSTRUCTION AND TRAINING
Provide Owner instruction and training in accordance with Section 230240.