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Project Name / Date Division 23 52 33.13 - 2
A. General
1. The water heater(s) shall be fired with
gas at a rated input of BTU/hr.
2. The water heater(s) shall be CSA tested and certified with a minimum thermal efficiency of 85
percent at full fire.
3. The water heater(s) shall be ASME inspected and stamped and National Board registered for
160 PSIG working pressure, complete with a Manufacturer's Data Report.
4. The water heater(s) shall have a floor loading of 45 lbs. /square foot or less.
B. Heat Exchanger
1. The heat exchanger shall be of a single-bank, horizontal-grid design with nine integral copper
fin tubes, each end of which is rolled into an ASME water heater quality steel tube sheet.
2. The heat exchanger shall be sealed to 160 PSIG rated bronze headers with high temperature
silicone "O" ring gaskets.
3. The low water volume heat exchanger shall be explosion-proof on the water side and shall
carry a twenty-year warranty against thermal shock.
4. The headers shall be secured to the tube sheet by stud bolts with flange nuts to permit
inspection and maintenance without removal of external piping connections. The heat
exchanger shall incorporate "V” baffles between the tubes to ensure complete contact of the
external tube surfaces with the products of combustion.
5. The water heater(s) shall be capable of operating at inlet water temperatures as low as 105°F
without condensation.
6. The heat exchanger shall be AB-1953 compliant in construction and verification by a third-
party certification agency.
C. Burners
1. The tubular burners shall have gas orifices, punched ports and slots, be capable of quiet
ignition and extinction without flashback at the orifice, and be manufactured from corrosion-
resistant, stainless steel with low expansion coefficient.
2. The burners will be supplied with a fan-assisted, clean burning, and highly efficient fuel-air
mixture.
D. Ignition Control System
1. The water heater(s) shall be equipped with a 100 percent safety shutdown system.
2. The ignition shall be Hot Surface Ignition type with full flame rectification by remote sensing
separate from the ignition source, with a three try-for-ignition sequence, to ensure consistent
operation.
3. The igniter will be located away from the water inlet to protect the device from condensation
during startup.
4. An external viewing port shall be provided, permitting visual observation of burner operation.
E. Gas Train
1. The water heater(s) shall have dual-seated main gas valve(s).
2. Gas control trains shall have a redundant safety shut-off feature, main gas regulator, and
plugged pressure tapping to meet the requirements of ANSI Z21.10.3/CSA 4.3.
F. Water Heater Control
1. The following safety controls shall be provided:
a. High limit control
b. Flow switch
c.
PSIG ASME pressure relief valve, piped by the installer to an approved drain
d. Temperature and pressure gauge
2. The water heater(s) shall be equipped with an energy-saving pump relay, mounted and wired,
which automatically shuts off the water heater pump at a set period after water heater shut-
down (adjustable for two settings of five or ten minutes) to avoid standby losses associated
with constant pump operation.
G. Firing Mode
1. For models HD101 – HD401, provide on/off control of the gas input to the water heater (two-
stage fire optional).