Gas Piping - AAON RM Series Installation Instructions Manual

GAS PIPING

Size gas piping to supply the unit with 6" to 10.5" water
column pressure for natural gas or 11" water column
pressure for propane when all gas consuming devices in
the building connected to the same gas system are
operating. Install piping in accordance with local codes,
the piping must conform with the latest ANSI-Z223.1
National Fuel Gas Code; in Canada, Current Standard
CAN / CGA-B149, Installation Codes for Gas Burning
Appliances and Equipment.
Some utility companies will require pipe sizes larger
than the minimum sizes listed.
GAS PIPING SIZES
UNIT SIZE / TONS
02 - 03
04
05 - 06 - 07
08 - 10 180 - 270 - 351
13 - 15 180 - 270 - 390
16 - 30 270 - 390 - 480
NOTE: Local Codes may require the use of a manual
main gas shut-off valve and union, (furnished by others)
installed in the gas line external to the unit.
GAS PIPING is to be supported DIRECTLY AT CON-
NECTION TO UNIT and must not be strained or bent
and shall be supported by metal straps, blocks or hooks
at intervals not to exceed that shown in the following
table:
GAS PIPING SUPPORT
SIZE OF PIPE
1/2"
3/4" or 1"
1 1/4" or larger (horizontal)
1 1/4" or larger (vertical)
Pipe joint compounds used on all gas piping connections
shall be resistant to the action of petroleum gases.
An 1/8" NPT plugged tap is required immediately ahead
of the unit gas control valve.
All piping connections shall be checked with a soap
solution for gas leaks before operating the appliance.
GAS PIPING CAPACITIES
Nominal Max. Capacity of Gas Pipe in Cubic Ft. Per Hour*
Iron Pipe
LENGTH OF PIPE, FEET
Size, Inches
10
3/4" 278
1" 520
1 1/4" 1050
1 1/2" 1600
2 3050
2 1/2" 4800
*At gas pressure of 0.5 PSIG or less and a pressure
drop of 0.5 inches of water. Specific gravity = 0.60.
PIPE SIZE
INPUT / MBH
69 3/4"
90 3/4"
90 - 180 3/4"
3/4"
3/4"
3/4"
INTERVALS (feet)
6'
8'
10'
every floor level
50 100 200
115 79
215 150
440 305
670 460
1270 870
2000 1400
INSTALLATION continued
Gas
Shut-off
Valve*
*Gas piping field installed by others
Gas piping information is for practical guidelines and is
typical for one gas valve. For units with dual heat
exchangers, duplicate gas piping to number two gas
valve.
GAS PRESSURE REGULATOR & OVER-PRESSURE
PROTECTION DEVICE
On applications where gas service to the unit is greater
than 10.5"w.c. and less than 2-psi, a gas pressure regu-
lator must be installed.
At supply pressures in excess of 2-psi and less than 5-
psi, ANSI Z21.80 line regulator standard requires a
means (an over-pressure protection device / OPD) to
limit the downstream pressure to 2-psi maximum, in the
event of regulator failure.
In compliance with the ANSI Standard, installations
exceeding 2-psi and less than 5-psi nominal require a
tested and approved over-pressure protection device for
use with the regulator.
For proper heater operation, pressure to the regulator
MUST NOT BE greater than 5-psi.
55
100
210
320
610
980
Optional
Gas Pressure Regulator
9
Utility
Access
Union*
GAS PIPING ILLUSTRATION
Heat
Exchanger
Gas
Valve