Table of Contents
Advertisement
D. Gas Supply Connections
The installation must conform completely to the
requirements of the authority having jurisdiction, or
in the absence of such, requirements shall conform in
the U.S. to the current National Fuel Gas Code, ANSI
Z223.1-1984, or in Canada to the current Natural gas
and propane installation code (CAN/CSA B149.1-05),
and applicable regional regulations for the class;
which should be followed carefully in all cases.
Authorities having jurisdiction should be consulted
before installations are made. Refer to paragraph
3.5.2 for gas supply requirements.
1. Drip Leg
a. A drip leg, or sediment trap, is supplied
with the gas train. The gas line must be
connected to a supply main at least as large
as the gas train connection at the boiler. This
connection should be made with a union so
that the boiler gas train components and
burner may be easily removed for service.
2. Gas Piping Leak Test
a. After completion of the gas-piping hookup,
the installation must be checked for leaks.
Leaks shall be checked using a soap and water
solution. All joints up to the main motorized
gas valve shall be checked. A pressure
gauge shall be installed down stream of the
main motorized gas valve and up stream of
the manual gas shutoff valve in the closed
position to ensure the main motorized valves
are not leaking by. During commissioning,
the remainder of the gas train joints down
stream of the main motorized gas valve shall
be tested for leaks.
3. Venting of Gas Train Components
a. The MBC (gas valve) has an internal, factory
installed vent limiter re ANSI Z21.18/ CSA 6.3.
Venting required unless otherwise accepted
by the authority having jurisdiction.
b. The high and low gas pressure switches
incorporate a vent limiter as per UL 353
and limits the escape of gas less than 1.0
CFH of natural gas at 7 PSI if internal switch
diaphragm ruptures.
12
Thermal Solutions, 1175 Manheim Pike, Lancaster, PA 17601 Website: www.thermalsolutions.com
Phone: 717-239-7642 Fax: 877-501-5212 Email: sales@thermalsolutions.com
E. Combustion Air Supply System
For proper combustion it is necessary to provide the
boiler room with appropriate openings for fresh air
supply. Temporary air intakes such as windows and
doors should be avoided since they may be closed.
In addition to air needed for combustion, sufficient
air must be supplied for ventilation as well as other
air consuming equipment that may be present in the
boiler room. Often when personnel are working in the
boiler room, combustion air openings are closed due
to the temperature of the outside air. THIS MUST BE
AVOIDED AT ALL COSTS! Provisions should be made
to heat the outside combustion air, if necessary, for
personnel comfort.
Positive means for supplying an ample amount of
outside air, allowing for the complete combustion of
the gas, must be provided.
Movable combustion air dampers, automatic or
manually adjustable, must be electrically interlocked
with the boiler to prevent boiler operation if the
dampers are closed.
Combustion air openings must never be blocked or
obstructed in any manner.
The boiler room must be at a positive or neutral
pressure relative to the outdoors. A negative in the
boiler room will result in downdraft problems and
incomplete combustion due to the lack of air.
WARNING
WARNING
Failure to provide an adequate air supply will result
in boiler damage and hazardous conditions in the
building (fire and asphyxiation hazard as well as
equipment damage).
The design of combustion air openings MUST comply
with local and/or State codes or the authority having
jurisdiction. As a minimum, combustion air openings
to the boiler room shall be provided as follows:
WARNING
WARNING
Combustion air provided solely from an indoor
source is discouraged. No dimension for a round or
rectangular opening shall be less than 3".
Advertisement
Table of Contents
