FloAire INDIRECT FIRED BENT TUBE MODULE - Manual (Page 11)

11
Gas Pressure Table
Gas Pressure Type Gas Pressure
Inlet Pressure - Natural Gas 7 in. w.c. – 14 in. w.c.
Inlet Pressure - Propane 11 in. w.c. – 14 in. w.c.
Max. Manifold Pressure - Natural Gas 3.5 in. w.c. maximum
Max. Manifold Pressure - Propane 10 in. w.c. maximum
Min. Manifold Pressure - Natural Gas 0.15 in. w.c. minimum
Min. Manifold Pressure - Propane 0.75 in. w.c. minimum
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 14 IN. W.C. SEE UNIT
RATING PLATE 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.