I W H

Instantaneous Water Heater

1. Especificaciones Generales:
• Furnish & install in accordance with the plans an Armstrong Instantaneous Water Heater, Model (enter model number) ___. The factory-assembled package shall be capable of heating (enter flow) ___ USgpm (m3/hr) of water from ___°F (°C) to ___°F (°C) when supplied with (enter boiler flow) ___ USgpm (m3/hr) of boiler water at ___°F (°C) and returning to the boiler at ___°F (°C) (minimum 140°F or 60°C). The package, mounted on a common base plate, shall include a Plate & Frame heat exchanger, a 3-way electronic control valve, a bronze-fitted vertical in-line pump, an all-bronze circulating pump complete with electric controls, valves and strainers, and all interconnecting piping. The entire package shall be hydrostatically tested and factory painted prior to shipment, and shall have a performance guarantee when installed and operated in accordance with the manufacturer’s instructions.

1. Heat Exchanger
• The ASME constructed & tested heat exchanger shall be assembled with 316 stainless steel Single-Wall plates and EPDM gaskets. To minimize the risk of cross-contamination, Double-Wall plates shall be specified. Tie rods, nuts and washers shall be zinc coated. Unit shall be rated for 125 psi (862 kPa) design pressure at 300°F (149°C) maximum operating temperature.

1. 3-way electronic control valve
• The electronically actuated mixing valve shall be ANSI rated to withstand the operating conditions. The valve shall have a metal to metal seat, stainless steel stem and replaceable cartridge-type EPDM packing for easy service. The valve shall be spring loaded to fail closed in case of power outage.

1. Pumps
• Armstrong Series 4380 close-coupled, single stage, single suction vertical inline centrifugal unit. The pump shall have a cast iron casing, an enclosed dynamically balanced bronze impeller, a bronze shaft sleeve and a single inside mechanical seal. The driving motor shall be industry standard, vertical solid shaft and squirrel cage induction type with ODP enclosure.

1. Circulating Pump
• Armstrong “H” series Circulating Pump with a capacity of ___ USgpm (m3/hr), handling water against a total head of ___ ft (m). Pump shall be equipped with a ___ hp (Kw), ___ volt, single phase, 60 Hertz, 1800 rpm drip-proof mounted motor. Circulator shall be all-bronze construction and the shaft shall have an oil-lubricated bronze sleeve bearing and an “ARMSEAL” mechanical seal.

1. Gauges
• The pump shall be provided with a 21/2” dial pressure gauge and threeway brass valving with copper tubing for measuring both suction and discharge pressure.

1. Control Panel
• A single enclosure NEMA 1 control panel, wired to the pumps and 3-way valve actuator, shall be provided. Panel shall have main disconnect interlocked with the door, a locking door handle provided with two keys, fuses for the pump motor and starters with 3-leg overload protection. Control circuit shall include fused primary and secondary control transformers with 24 & 120- volt secondary, H-O-A switch for the primary pump and ON/OFF switch for the circulating pump. Control Panel shall be UL & CSA listed. The control panel includes either a basic temperature controller or enhanced controller described below.
• Basic Control: Advanced PID digital temperature controller with one Type J thermocouple sensing DHW supply temperature. Serial communication interface available as option.
• Enhanced Control: Custom designed digital temperature controller with six Type J thermocouples shall incorporate a feed forward controller for more accurate temperature control to address changes in boiler supply temperature transients. Communications interface with BAS networks, a master-slave ability to sequence parallel IWH units for high flow applications, smart energy saving “sleep mode” logic, and night time temperature setback energy saving logic shall be standard features.

1. Temperature Controller
• The temperature controller in the control panel monitors hot water (HW) supply temperature and HW usage using feedback and feed-forward compensation principles. The temperature controller controls the 3-way mixing valve to maintain a constant HW temperature supply. The Proportional plus Integral control of the temperature controller shall be factory set via simulated site condition testing and shall adapt to continuous changing demands.

1. Piping, Baseplate and Test
• Interconnecting piping on the primary (boiler) side shall be schedule 40 black steel pipe while regular red brass piping shall be supplied on the secondary
  (hot water) side of the heat exchanger. Suitable union connections shall be provided in the piping to allow removal of the heat exchanger or other major components without disturbing system piping. Baseplate shall be constructed of heavy duty welded structural steel. The complete package shall receive a hydrostatic test prior to shipping.