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PHWS – Specifications

Model PHWS Packaged Hot Water Generator

Specification

1. General

Furnish and install as shown on the plans one (1) PRECISION model PHWS-H horizontal (or -V, vertical) packaged hot water generator. Generator shall provide _____gallons per hour of potable water at 140 F when supplied with city water at_____ F and steam at____psig (boiler water at ____ F). Heater storage section shall have a diameter of _____inches, a capacity of ____gallons and shall be designed for 125 psig. Packaged generator shall be completely factory assembled with controls and trim as specified below.

2. Pressure Vessel

 

Vessel shall be constructed and stamped in accordance with ASME Section IV HLW and shall be registered with the National Board. Shell shall be fabricated from carbon steel, with integral 12″ by 16″ manway, and shall be furnished with [choose one of]:

“Precision Seal” polymerized epoxy lining with carbon steel fittings and 5 year manufacturer’s limited warranty [max temp 1600 F].

“Coppercoat” TM lining with carbon steel fittings and 10 year manufacturer’s limited warranty [max temp 1600 F].

“Nickelcoat” lining with carbon steel fittings and 1 0 year manufacturer’s limited warranty [max temp 1600 F].

Aluminum silicate cement lining with 304 stainless steel fittings and 10 year manufacturer’s limited warranty [max temp 2100 F].

All fittings, nozzles and joggled joints shall be seal welded internally to eliminate crevices between pressure boundary parts. Storage vessel shall be fitted with a removable U tube heating coil with non-ferrous tubesheet and separator. Tubes shall be (select one of):

  • 3/4″ OD single wall seamless SB75 copper tubes with 20 BWG [0.035″] wall.

  • 3/4″ OD single wall seamless SB111 cupro-nickel tubes with 20 BWG [0.035″]wall.

  • 3/4″ OD single wall SA240-304 stainless steel tubes with 20 BWG [0.035″] wall.

  • 3/4″ OD single wall SA240-316 stainless steel tubes with 20 BWG [0.035″] wall.

  • 3/4″ OD double wall, seamless SB75 copper tubes with integral leak detection passages.

Heating capacity of coil shall be ____GPH at ____ F to ____ F temperature rise using steam at ____ psig inlet pressure to control valve. (Water at ____ F inlet temperature and ____psig pressure to control valve.)

3. Steam-to-Water Generator Controls

Steam-to-water generator shall be provided with the following controls: Factory installed steam control valve with steam capacity of______Ib/hr at _____ psig inlet pressure to vary the flow of steam to the heating coil in response to variations in storage tank temperature. Control valve shall be self contained, self-operating (pneumatic, diaphragm actuated, spring to close in event of air failure.) (pilot-operated)(electric actuated) with upstream strainer. Trim shall include properly sized ASME pressure- temperature relief valve, manual drain valve, water thermometer and pressure gauge, all tank mounted; float and thermostatic steam trap on coil outlet and auxiliary steam trap on upstream side of control valve, both piped to common condensate outlet; and (vacuum breaker on tank coil cap).

4. Water-to-Water Generator Controls 

Water-to-water generator shall be furnished with the following controls: Factory installed heating water 2-way or 3-way diverting control valve with water capacity of _____GPM at inlet temperature of _____ F to vary the flow of heating water to the coil, in response to variations in storage tank temperature. Control valve shall be self contained, self operating (pneumatic, diaphragm actuated, spring-to-close in event of air failure)(electric actuated) with upstream
strainer. Trim shall include properly sized ASME pressure-temperature relief valve, water thermometer, water pressure gauge and manual drain valve, all tank mounted; (heating water pressure gauge) (heating water inlet/outlet temperature gauges)(high temperature cutout).

5. Integral Circulation System

Provide baffled heating coil with wrapper and bronze circulator, factory piped with copper tubing and bronze- bodied isolating ball valves.

6. Packaging

Complete package shall be factory assembled and mounted on structural channel support skid. All specified components are to be mounted, piped (and wired). Tank shall be insulated with 2 inches of heavy duty fiberglass to conform to ASHRAE 90.1 and housed in a rectangular, 16 gauge enamel painted steel jacket. Lift lugs shall be provided to allow rigging of package during installation.

7. Quality Control

Complete packaged generator shall be manufactured by PRECISION Boilers, LLC in strict accordance with ASME Boiler and Pressure Vessel Code and ISO 9002 Quality Standard.

Specifications subject to change without notice.