Products:  Electric:  HWS

Model HWS Packaged Hot Water Generator

Specification

Note:  items shown in parenthesis () are options.

1. General

Furnish and install as shown on the plans a PRECISION Storage Water Heater Model HWS-which shall be a complete Factory tested, packaged unit consisting of an electrically-heated water storage vessel complete with all required operating and safety controls.

The pressure vessel shall meet all the applicable requirements for ASME Section IV and stamped HLW and shall be National Board Inspected and designed for (125) (150) PSIG maximum working pressure. A copy of the Manufacturer's Data Report shall be provided to the owner.

The completed Hot Water Storage Heater shall be UL listed and be installed in accordance with all applicable state and local codes.

2. Recovery

Each Hot Water Storage Heater shall have an electrical heating capacity of_____KW for operation at a line voltage of_______, 3 phase, ______hertz. The control voltage shall be 120 volts derived from an integral control transformer.

Note for steam dual fired heater:

Heater shall also be provided with steam coil and controls rated to heat GPH of water fromof toof temperature rise and to control the outlet within 5 degrees of the selected temperature when supplied with _____PSIG saturated steam to the control valve.

3.  Controls and Safety Devices

Load Sequencing:

Units of 4 or less steps - The Hot Water Heater shall be equipped with on/off thermostats to provide not less than _____ stages. The limit circuit shall consist of a high limit thermostat (automatic reset), a high limit thermostat-(manualreset), internal branch circuit fusing, magnetic contactors, a float-type low water cutoff, and pilot lights (one per stage).

Units of 5 or more steps - The Hot Water Heater shall be equipped with a proportional step control to provide not less than ____ steps. The control circuit shall consist of a proportional temperature controller with adjustable throttling range, a high limit thermostat (automatic reset), a high limit thermostat (manual reset), internal branch circuit fusing, magnetic contactors, an on/off switch with pilot light, a recycle feature, a float-type low water cutoff, and pilot lights (one per step).

Each Heater shall be equipped with an ASME pressure and temperature relief valve, a combination pressure and temperature gauge, and an integral electric control panel with key-locked door.

4.  Construction

Heater shall be constructed of a (vertical) (horizontal) steel tank  ____” (inches) diameter x______"(inches) (long) (high) and shall have a storage capacity of ______ gallons.

The immersion heating elements shall be Incoloy-sheathed individually flanged and sized for a maximum of 75 watts per square inch. The U-bend shall be heat treated and re-compressed after forming, to avoid failure due to stress cracks in the bend, and then brazed into a 2-1/2" square steel flange.

The pressure vessel shall be insulated with a minimum of 4 inches of 3/4 pound density fiberglass insulation (or equivalent) and shall be enclosed in a enamelled sheet steel enclosure of at least 16 gauge thickness.

The Heater shall be furnished with an 11" x 15" manway, ______" inlet,"_____ outlet, drain pipe and valve, and lifting lugs.

5.  Vessel Lining

Heater shall be completely lined AFTER FABRICATION with (Precision Seal) (Copper Coat™)  (Cement) lining as follows:

(Insert one of the following paragraphs that applies to your selection of linings)

5.1 Seal: The tank interior shall be lined with two separate coats of polymerized epoxy to a dry film thickness of 5-6 mils per coat. Each coat shall be baked and force-cured in an oven.

5.2 Copper Coat: The tank interior shall be lined with 100% dead soft copper by using the "Thermometalization Process", creating a non-ferrous, corrosion-resistant protective surface. In addition, the tank shall be equipped with a Copper Coat™ manway cover and Copper Coat™ threaded tank openings. The copper shall then be overcoated with two (2) separate coats of Precision Seal to a dry thickness of 10 - 12 mils.

5.3 Cement Lined: The tank interior shall be completely lined with aluminum silicate cement, good for service temperatures to 250°F with the same coefficient of expansion as medium steel. The cement is applied at a minimum thickness of 5/8" to form a hard one-piece lining.