3.2.19
Thermometer Wells
A thermometer well shall be provided in each return line for each circuit
in multicircuit systems.
3.2.20
Air Vents
Air vents shall be installed where shown or directed. Air vents shall be
installed in piping at all system high points. The vent shall remain open
until water rises in the tank or pipe to a predetermined level at which
time it shall close tight. An overflow pipe from the vent shall be run to
a point designated by the Contracting Officer's representative. The inlet
to the air vent shall have a gate valve or ball valve.
3.2.21
Escutcheons
Escutcheons shall be provided at all finished surfaces where exposed
piping, bare or insulated, passes through floors, walls, or ceilings except
in boiler, utility, or equipment rooms. Escutcheons shall be fastened
securely to pipe or pipe covering and shall be chromium-plated iron or
chromium-plated brass, either one-piece or split pattern, held in place by
internal spring tension or setscrews.
3.2.22
Drains
A drain connection with a 25 mm 1 inch gate valve or 20 mm 3/4 inch hose
bib shall be installed at the lowest point in the return main near the
boiler. In addition, threaded drain connections with threaded cap or plug
shall be installed on the heat exchanger coil on each unit heater or unit
ventilator and wherever required for thorough draining of the system.
3.2.23
Strainer Blow-Down Piping
Strainer blow-down connections shall be fitted with a black steel blow-down
pipeline routed to an accessible location and provided with a blow-down
valve.
3.2.24
Direct Venting for Combustion Intake Air and Exhaust Air
**************************************************************************
NOTE: Delete this paragraph if condensing boilers
are not used.
**************************************************************************
The intake air and exhaust vents shall be installed in accordance with NFPA
54 and boiler manufacturer's recommendations. The exhaust vent shall be
sloped 20.8 mm per m 1/4 inch per ft toward the boiler's flue gas
condensate collection point.
3.3
GAS FUEL SYSTEM
Gas piping, fittings, valves, regulators, tests, cleaning, and adjustments
shall be in accordance with the Section 15190A GAS PIPING SYSTEMS. NFPA 54
shall be complied with unless otherwise specified. Burners, pilots, and
all accessories shall be listed in UL Gas&Oil Dir. The fuel system shall
be provided with a gas tight, manually operated, UL listed stop valve at
the gas-supply connections, a gas strainer, a pressure regulator, pressure
gauges, a burner-control valve, a safety shutoff valve suitable for size of
burner and sequence of operation, and other components required for safe,
SECTION 15569A
Page 71
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