Specifications include, but are not limited to: Design & Construction: Each heater shall be of the counter-current flow stainless steel brazed plate heat exchanger designed and manufactured in accordance with ASME Code Section VIII, Div. 1 for 435 psig @ 300ºF. The packaged heater shall be rated for not less than 200 psig on the service water side and not less than 150 PSIG, 250°F on the boiler water side. The plates shall be 316L stainless steel, brazed together using copper. Electronic Control System: The heater shall maintain +/- 2°F Max temperature fluctuation from temperature setpoint at 0% to 100 % load at a constant load and +/- 4°F under normal diversified domestic load conditions. The system shall consist of a 3-way electronic control valve, constant speed domestic water circulator pump, control panel enclosure housing a PID temperature controller with digital indication of shell outlet water temperature, boiler water inlet and boiler water outlet temperatures, digital over-temperature limit switch, and feed-forward and feedback temperature sensors. The controller shall close the control valve in an over-temperature condition. The system shall have the following additional characteristics: Controller temperature setpoint range between 50°F to 180°F maximum Configured for 120V/1Phase/60 Hz, 220V/1Phase/60 Hz and 220V/1Phase/50 Hz Easy start-up. Dial in setpoint & walk away. The electronic control valve shall be of equal percentage flow characteristics, and has a tight shut-off with low leakage rate of .02% of its Cv value. The valve shall have the following performance characteristics: 1000 to 1 Turndown. Magnetic Actuator with Fail Closed Design-particularly on loss of power Time to Full Open Position: 2 seconds Time to Full Closed Position: 2 seconds The PID temperature controller shall incorporate a feed-forward function and be password protected. The following information shall be accessible locally at the controller: Setpoint Outlet Temperature Over Temperature Alarm Control Output Signal to valve Each heater shall be supplied by the manufacturer ready to accept existing boiler water and domestic water lines, and furnished with the following accessories: Y-strainers with blowdown valve for boiler water and domestic water. Boiler water strainer differential pressure gauge. Bronze T & P relief valve, conforming to ANZI Z21.22, set at 150 PSIG/210°F or Pressure Relief Valve set at 200 PSIG Bronze ball type isolation valves. 3/4" Bronze domestic water drain valve. Domestic water Air Vent rated for either 150 PSIG operation or 200 PSIG operation accordingly. In-place connections for easy and simple cleaning of the brazed plate heat exchanger.