GAS WATER HEATERS SPECIFICATIONS Revised 03.02.2021.pdf

Specifications (Revised) Tankless Water Heaters

(11) - High Efficient Natural Gas, Free-Standing, Tankless Water Heaters for (purchase only). Vendor must be able to meet and /or exceed the following specifications in order to be considered.

• High Efficient Gas Tankless Water Heaters

• Condensing water heaters must be constructed in accordance with ASME Water heater and

Pressure Vessel Code, Section IV (HLW) Potable Water.

• Water heaters shall include manufacturer's standard form in which manufacturer agrees to repair or replace components of water heaters that fail in materials or workmanship within specified warranty period. Potential bidders can include any additional warranty information that is available.

• Each water heater shall be ETL Listed; ASME Section IV (HLW) coded and stamped and shall incorporate a negative Pressure gas valve on each exchanger capable of full fire operation at of 2.5"

• Each with a minimum input of 499,999 MBH, output of 470 MBH, 564 GPH, (9.4 GPM) at 40-140 oF when fired with natural gas, turndown ratio 13.3:1, CO emissions of less than 400 PPM.) (2) 250MBH (approx.) Heat Exchangers.

• Power burner shall have full modulation. The minimum firing rate shall not exceed 30,000 BTU/HR input. Water heaters that have an input greater than 30,000 BTU/hr at minimum fire will not be considered equal.

• Water heater shall have an operational set point capability of 100 F to 190 F and shall maintain outlet temperature within an accuracy of +/-4 oF during load changes of up to 30% rated capacity.

• Water heater shall be factory-fabricated, factory- assembled, and factory-tested.

• Heat exchanger shall be constructed with 316L stainless steel helical water tube, fully floating with no welded joints in the exchanger.

• Water tubes shall be 0.75” ID, with no less than 0.0472” wall thickness.

• Heat exchanger shall be ASME Sect IV (HLW) stamped for working pressure not less than 160 psig.

• The water heater burner shall be capable of a 16.6-to-1, turndown ratio of the firing rate without loss of combustion efficiency or staging of gas valves.

• Burner shall be stainless fiber mesh covering a stainless steel body with spark ignition and flame rectification.

• All burner material exposed to the combustion zone shall be of stainless steel construction.

• There shall be no moving parts within the burner itself.

• A modulating air/fuel valve shall meter the air and fuel input.

• The exhaust manifold shall be of polypropylene with a 4" diameter flue connection.

• Ignition shall be via spark ignition with 100 percent main-valve shutoff and dual electronic flame supervision.

• The control panel shall consist of one individual circuit. The circuit boards shall include, a digital touch display to indicate temperature and status and a CPU board housing all control functions.

• The unit shall have a selectable exhaust temperature limit suitable for venting with PVC or

CPVC/Polypropylene/Stainless Steel (AL29-4C).

• The controls shall annunciate water heater and sensor status and include extensive self-diagnostic capabilities.

• The water heater control system shall incorporate the following additional features for enhanced external system interface: Temperature set point; High Exhaust temp monitor and control.

• Turn down the Gas valve until the exhaust temp is kept below selected material (PVC or CPVC).;

Cascading via RS232; Error Code Display / Error Code History; Blower Fault; Blocked Flue Fault;

Ignition Failure; Temp Sensor Short; Temp Sensor Wiring Fault; Flue Temp Fault; Heat Exchanger Temp Fault; Cascading Fault; Water Valve Fault; Pump Fault; Software Fault. Monitor and access to daily, weekly, monthly water usages data. Monitor inlet/outlet temperatures, flow rates, flue gas temperatures, combustion rates via onboard touchscreen.

• The water heater control system shall incorporate onboard multi-unit sequencing logic that would allow Master-less Cascading (Not Lead/Lag) functionality & sequencing between multiple water heaters operating in parallel and must have the following capabilities:

o Efficiently sequence 2 up to 8 (~2,000,000 Btu) heat exchangers on the same system to meet the load requirement.

o Individual heat exchanger logic to enable accurate temperature control.

o Operate one motorized valve per heat exchanger as an element of the load sequencing, Valves shall close with decreased load as heaters turn off, minimum of one (depending upon Mode selection) must always stay open for recirculation.

o Automatically rotate Start/Stop amongst the heat exchangers in the chain based upon an internal calculation of run hours, water through put, burner starts and stops and length of time each burner has been firing.

o Sequencing is not based upon next in line (Lead/Lag), it is based upon the most logical (least used) heat exchanger in an effort to equalize unit run hours.

o Automatic bump-less transfer of sequencing in case of heat exchanger failure. All systems must be able to fail all but one heat exchanger in any order or for any reason and the last will continue to operate.

o Each heat exchanger will default to individual control upon failure of the sequencing chain.

o Automatic isolation of heat exchanger module from water circuit in case of failure and prevention of cold water from exiting the system.

o Master-less control, change any parameter in any one of the units and all the rest in the series will automatically adjust to the most recent parameter change.

• Single-Point Field Power Connection: Factory-installed and factory-wired switches, motor controllers, transformers and other electrical devices shall provide a single-point field power connection to the water heater.

• Electrical Characteristics:

o -Voltage: 120 V o -Phase: Single o -Frequency: 60 Hz o -Full-Load Current 5 Amps or less per 200,000 BTU of heat input.

• Condensate traps, manufactured from only non-corrosive materials.

• Smart condensate neutralizer with capability of monitoring pH levels through included IoT app.

• Appropriate size condensate neutralizer (ADDED)

• Smart Neutralizer to also include: (REMOVED) o Monitor water temperatures o CO detection o Flue gas detection o Water leak detection of boiler room w/audible/visual alarms o Water flow recording/monitoring

• The exhaust vent must be PVC, CPVC, Polypropylene, Stainless Steel (AL29-4C) compatible with positive pressure, condensing flue gas service.

• The minimum exhaust vent duct size for each water heater is six-inch diameter.

• The minimum sealed combustion air duct size for each water heater is 4" diameter.

• Perform tests and inspections and prepare test reports.

• Start-up, Leak, Operational, Controls & Safeties Test.