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XII. Gas Piping
A. Guidelines and Requirements
All installation must conform to the National Fuel
Gas Code ANSI Z223.1/NFPA54, and/or local codes.
In Canada, installation must conform to the latest
edition of CSA B149.1 National Gas and Propane Gas
Installation Code, and/or local codes.
Safe operation of the appliance requires properly sized
gas supply piping. Design gas piping system to provide
adequate gas supply to the appliance. Account for
existing and expected future gas utilization equipments
such as boilers and cooking equipment.
1. First verify that the appliance is supplied with the
type of gas specified on the rating plate.
2. Account for pressure drop from the point of
delivery to the appliance. The maximum allowable
system pressure is ½ psig (14 in. wc). Refer to
Table 34 for model specific gas pressures and gas
connection sizes.
3. If the gas supply pressure is higher than 14 in. wc,
An additional field supplied pressure regulator will
be required.
4. For length of piping and number of fittings refer
to and Table 31 for maximum capacity of Schedule
40 pipe. Table 32 lists equivalent pipe length for
standard fittings.
5. Gas piping systems for gas specific gravity of 0.60
can be sized directly from Table 31 unless authority
having jurisdiction specifies a gravity factor be
applied. For other specific gravities, apply gravity
factor from Table 33. If exact specific gravity is not
shown choose next higher value.
6. A sediment trap must be provided upstream of the
main gas valve. (Included on AMPs with vertical gas
train connections)
7. All threaded joints should be coated with piping
compound resistant to action of liquefied petroleum
gas.
8. The appliance and its gas connection must be leak
tested before placing it in operation.
a. To protect the gas valve when testing over 1/2
psig (3.4 kPa), the appliance and its individual
shutoff valve must be disconnected from gas
supply piping. For testing at 1/2 psig (3.4 kPa)
or less, isolate the appliance from gas supply
piping by closing the manual shutoff valve on
the appliance.
b. Locate leaks using approved combustible gas
non-corrosive leak detector solution.
9. The incoming gas pressure can be measured at the
pressure tapping on the manual ball valve.
10. If the high or low gas pressure switch tripped, it
must be manually reset before the appliance can
be restarted. (See Figure 29)
11. Gas piping shall be supported by fixed hangers or
stands and not by the appliance.
12. Purge all air from gas lines.
13. Install manual shutoff valve in accordance with
state and local requirements.
Figure 28: The AMP Gas Train
Venting of Gas Train Components: The MBC (gas
valve) has an internal factory installed vent limiter
per ANSI Z21.18/ CSA 6.3. Venting is required
unless otherwise accepted by the authority having
jurisdiction.
The high and low gas pressure switches incorporate
a vent limiter as per UL 353 and limits the escape
of gas to less than 1.0 CFH at 7 PSI if the internal
diaphragm ruptures.
Locate the field supplied gas pressure regulator a
minimum of 10 ft from the appliance with no more
than 1 elbow in-between.
59
Pressure Tapping
Manual Shut-off Valve
(factory supplied)
Must install within 6 ft
(1.8 m) of the appliance
Union
Manual
Shut-off Valve
Blower
connection
Gas Valve
NOTICE
NOTICE
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