FloAire Compact Direct Fired Heater - Manual (Page 8)

8
Gas Pressure Table
Gas Pressure Type Gas Pressure
Natural 5 in. w.c. – 14 in. w.c.
LP 5 in. w.c. – 14 in. w.c.
Gas Connection Sizes
Unit Size Gas Pipe Size
(NPT)
76 1/2”
Gas Connection Diagram
Gas
Installation of gas piping must conform with local building codes, or in the absence of local codes, with the
National Fuel Gas Code, ANSI Z223.1 (NFPA 54) – latest edition. In Canada, installation must be in
accordance with CAN/CGA-B149.1 for natural gas units and CAN/CGA-B149.2 for propane units.
WARNING: INLET GAS PRESSURE MUST NOT EXCEED PRESSURE INDICATED
ON NAMEPLATE. SEE UNIT NAMEPLATE FOR PROPER GAS SUPPLY
PRESSURE AND GAS TYPE.
1. Always disconnect power before working on or near a heater. Lock and tag the disconnect
switch or breaker to prevent accidental power up.
2. Piping to the unit should conform with local and national requirements for type and volume of gas
handled, and pressure drop allowed in the line. Refer to the Gas Engineer’s Handbook for gas
line capacities.
3. The incoming pipe near the heater should be sized to
match the connection on the outside of the unit. Unit inlet
sizes are shown in the table to the right. Avoid multiple
taps in the gas supply so the unit has a steady supply of
gas at all times.
4. Install a ground joint union with brass seat and a manual
shut-off valve external to the unit casing, as shown below,
adjacent to the unit for emergency shut-off and easy servicing of controls.
5. Provide a sediment trap, as shown below, before each unit and where low spots in the pipe line
cannot be avoided.
6. Blow out the gas line to remove debris
before making connections. Purge line to
remove air before attempting to start unit.
Purging of air from gas lines should be
performed as described in ANSI Z223.1-
latest edition “National Fuel Gas Code”, or
in Canada in CAN/CGA-B149.
7. All field gas piping must be pressure/leak tested prior to unit operation. Use a non-corrosive
bubble forming solution or equivalent for leak testing. The heater and its individual shut-off valve
must be disconnected from the gas supply piping system during any pressure testing of that
system at test pressures in excess of ½ psi. The heater must be isolated from the gas supply
piping system by closing its individual manual shutoff valve during any pressure testing of the gas
supply piping system at test pressures equal to or less than ½ psi.
8. This unit requires a constant 5 in. w.c. minimum
natural gas supply, when the unit is operating at
maximum gas flow. If the gas supply exceeds 14
in. w.c. it will damage the internal valve
components, and if it is below 5 in. w.c., the heater
may not perform to specifications.
NOTICE
Refer to the heater rating
plate for determining the
minimum gas supply pressure
for obtaining the maximum
gas capacity for which this
heater is specified.