Attachment 2b - Specifications and Drawings.pdf

Attachment #2 – J01302 Boiler Specifications

The boiler specifications include the following with an example being the Thermal Solutions Arctic condensing boiler ARC-3000:

Boiler:

a. Meet the Buy America Act clause of the umbrella contract

b. Boiler shall be AHRI certified with a minimum efficiency of 95%

c. The boiler shall be factory assembled & packaged as a complete unit and be shipped on a heavy steel frame or knockdown configuration. Packaged unit shall be complete with jacket, gas manifold, burner, and controls mounted and wired. The boiler shall be factory fire tested prior to shipment

d. The boiler shall be constructed in conformance to ASME Section IV and UL 795. The boiler shall bear the ASME “H” stamp and be National Board Listed for 160 psi MAWP at 210°F. The gas train and safety controls shall conform to requirements of UL 795 and ASME CSD-1

e. The boiler shall be complete with a 16 gauge metal jacket, steel casing, finished with a suitable heat resisting powdered coated finish. It shall be constructed on a structural steel frame and properly insulated with 1 inch thick insulation. The complete jacket shall be easily removable and reinstalled. The boiler shall incorporate individually removable jacket doors, with handles providing easy access to combustion chamber access panels. The entire tube area shall be easily accessible for fireside cleaning from one side

f. Pressure vessel shall be constructed of 316L stainless steel non-welded flexible serpentine water tubes connected to 316L stainless steel headers. All tubes:

i. Shall be easily removed and or replaced in field without welding or rolling and may be demonstrated upon request;

ii. Shall not require ASME “R” stamp for tube replacement; and

iii. Shall provide lifetime, shockproof seal on tube to header attributed to unequal expansion.

g. Heat exchanger shall be capable of operating up to 100°F delta T

h. Boiler shall be capable of variable primary or primary/secondary piping arrangements

Combustion System:

i. The burner shall be a metal fiber mesh burner with no moving parts capable of operating low NOx operation without additional components. The burner shall fire in a full 360-degree pattern providing uniform heat transfer. A viewing port shall be provided for visual observation of burner performance

j. Burner operation shall provide infinite modulation with minimum 5:1 turn down utilizing a Variable Speed Combustion Blower and air-fuel ratio control gas valve for dependable, repeatable modulation and precise combustion control. The gas valve design shall incorporate two safety valves in a single body and include the gas pressure regulator. Dampers, linkages or a single-speed fan is not acceptable

k. The ignition system shall be direct spark ignition with a UV scanner

l. The entire ignition and firing control sequence shall be monitored by a UL approved commercial-type microprocessor based integrated flame safeguard burner control with first out fault annunciation and operating sequence and diagnostic indicator lights. The burner control shall incorporate both pre-purge and post-purge timing functions

m. The gas train shall be UL/CSD-1 compliant with a supply gas pressure range of 4”wc - 14”wc using Natural Gas. The gas train shall consist of high and low gas pressure switches (each with manual reset), a manual shut off valve upstream of burner and downstream of last gas valve. A single main gas valve body shall perform the functions of safety shutoff, constant pressure regulation and air-fuel ratio control

n. The boiler electrical control circuit shall include a 120V limit string containing a low water cut off, water flow switch, high limit manual reset, blocked condensate switch, burner fuse, low gas pressure switch, high gas pressure switch, blocked vent switch, combustion air/fuel proving switch. Operating Control will use UL listed water temp sensors (UL353) and include both a supply sensor and return sensor as standard equipment with the option of adding a remote water temperature sensor as well as an outdoor air temperature sensor that can be shared for peer to peer operation. CSD-1 compliant.

Boiler Control System:

o. The Boiler Control System shall provide safety interlocks and water temperature control. The control system shall be fully integrated into the boiler control cabinet and incorporate single and multiple boiler control logic, inputs, outputs and communication interfaces. The control system shall coordinate the operation of up to eight (8) fully modulating hot water boilers and circulation pumps

p. Using PID (proportional-integral-derivative) based control, the remote system water temperature shall be compared with a set point to establish a target boiler firing rate. If the secondary loop flow speed is greater than the primary loop flow speed, firing rate is increased in response to the decrease in secondary loop temperature. When the remote system temperature is near the boiler high limit temperature, the boiler supply sensor shall limit the maximum boiler supply temperature to prevent boiler high limit events. Alternately, using parameter menu selections, the control system shall allow the boiler to respond directly to boiler supply temperature and set point to establish a target boiler firing rate while remote system water temperature is used for display purposes only. Each boiler’s fuel flow control valve shall be mechanically linked to the air flow control device to assure an air rich fuel/air ratio. All the automated logic required to ensure that pre-purge, post-purge, light-off, and burner modulation shall be provided

q. When the controller is in the local control mode, the control system shall establish the set point based on outside air temperature and a reset function curve, or be manually adjusted by the operator. When enabled, the set point shall be adjusted above a preset minimum set point upon sensing a domestic hot water demand contact input. When in remote mode, the control system shall accept a 4-20ma or Modbus [*OPTION: 0-10Vdc] remote set point or firing rate demand signal from an external EMS

r. A touch screen message display shall be provided to display real time BTU/hr., numeric data, startup and shutdown sequence status, alarm, system diagnostic, first-out messages and boiler historical information. In the event of a fault condition, the display shall provide help screens to determine the cause of the problem and corrective actions. Historical information shall include graphical trends, lockout history, and boiler & circulator cycle counts and run time hours

s. The controller shall be capable of sequencing the boiler, domestic hot water, or system circulators. Simple parameter selections shall allow all three pumps to respond properly to various hydronic piping arrangements including either a boiler or primary piped indirect water heater. The controller shall perform circulator exercise to help prevent pump rotor seizing

t. EMS Communication – Control and monitor the boiler via communication RS485 Modbus or direct wiring. The control shall allow for simultaneous communication for boiler peer-to-peer communication and EMS communication interfaces. Loss of EMS communication shall automatically transfer the boiler control to local operation. Boiler operation shall not be lost due to corrupt or loss of EMS communication. The boiler control system shall allow individual boiler limits, lockout, boiler and system temperatures, and firing rate status to be readable; and water set point, boiler firing rate, and start/stop command to be readable and writable. The control shall provide easy parameter selection and options for the following: Modulation Source (4-20ma or Modbus [*OPTION: 0-10Vdc]); Set point Source (4-20ma or Modbus [*OPTION: 0-10Vdc]); and Enable/Disable (contact wired or Modbus). The control shall allow a real time, live & convenient list of all interface signals to allow for quick interface verification.

The boiler control system shall network with a communication gateway to connect with LonWorks

u. It shall be possible to restore parameters to the “as shipped state” by selecting a “Factory Default” button

v. All hard lockouts, soft lockouts (holds), sensor faults, Energy Management System (EMS) signal faults, sequencer faults and limit string faults shall be recorded with a time and date stamp. The time and date log shall store up to 3000 alarm & events even after power cycle. The alarm & event log must be downloadable to a USB thumb drive. The control shall include collect and store supply & return temperature, flame intensity, and firing rate for at least 4 months. It shall be a simple matter to page through the boiler’s operation using the boiler mounted display or download the historical data to a USB thumb drive for off-site analysis. All data must be stored in standardly compatible CRV files.

w. The boiler control system shall be supplied as part of a factory-assembled and tested burner control cabinet