Installation and Service Manual

12
6-584.13
INSTALLATION - GAS CONNECTIONS
GAS CONNECTIONS
1. Installation of 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 CSA-B149.1.
2. Piping to units should conform with local and national
requirements for type and volume of gas handled, and
pressure drop allowed in the line. Refer to Table 12.1 to
determine the cubic feet per hour (CFH) for the type of gas
and size of unit to be installed. Using this CFH value and the
length of pipe necessary, determine the pipe diameter from
Table 12.2. Where several units are served by the same
main, the total capacity, CFH and length of main must be
considered. Avoid pipe sizes smaller than 1/2". Table 12.2
allows for a 0.3" W.C. pressure drop in the supply pressure
from the building main to the unit. The inlet pressure to the
unit must be 6-7" W.C. for natural gas and 11-14" W.C. for
propane gas. When sizing the inlet gas pipe diameter, make
sure that the unit supply pressure can be met after the
0.3" W.C. has been subtracted. If the 0.3" W.C. pressure drop
is too high, refer to the Gas Engineer’s Handbook for other
gas pipe capacities.
3. Install a ground joint union with brass seat and a manual
shut-off valve adjacent to the unit for emergency shut-off
and easy servicing of controls, including a 1/8" NPT plugged
tapping accessible for test gauge connection (see Figure 12.1).
4. Use 2 wrenches when connecting field piping to units.
5. Provide a sediment trap before each unit in the line where
low spots cannot be avoided (see Figure 12.1).
6. When pressure/leak testing, pressures above 14" W.C.
(1/2 psi), close the field installed shut-off valve, disconnect
the appliance and its combination gas control from the gas
supply line, and plug the supply line before testing. When
testing pressures 14" W.C. (1/2 psi) or below, close the
manual shut-off valve on the appliance before testing.
Figure 12.1 - Recommended Sediment Trap/Manual
Shut-off Valve Installation - Side or Bottom Gas
Connection j
j Manual shut-off valve is in the “OFF” position when handle is perpendicular to pipe.
IMPORTANT
To prevent premature heat exchanger failure, the input to the
appliance, as indicated on the serial plate, must not exceed
the rated input by more than 5%.
Table 12.1 - Sea Level Manifold Pressure &
Gas Consumption
Natural Propane
Model BTU/Cu. Ft. 1050 2500 No. of
Size Specific Gravity 0.60 1.53 Orifices
Manifold Pressure In. W.C. 3.5 10.0
CFH 28.6 12.0 2
Gal/Hr. Propane .33
Sec/cu. ft. 126 300
Orifice Drill Size 49 56
CFH 42.9 18.0 3
Gal/Hr. Propane .50
Sec/cu. ft. 84 200
Orifice Drill Size 49 56
CFH 57.1 24.0 4
Gal/Hr. Propane .66
Sec/cu. ft. 63 150
Orifice Drill Size 49 56
CFH 71.4 30.0 5
Gal/Hr. Propane .83
Sec/cu. ft. 50 180
Orifice Drill Size 49 56
CFH 95.2 40 5
Gal/Hr.Propane 1.09
Sec/cu. ft. 38 90
Orifice Drill Size 45 55
CFH 119 50 5
Gal/Hr.Propane 1.37
Sec/cu. ft. 30 72
Orifice Drill Size 42 53
30
45
60
75
100
125
Pipe
Length (ft)
Natural Gas
1/2" 3/4" 1" 1-1/4" 1-1/2" 2"
10 132 278 520 1050 1600 3050
20 92 190 350 730 1100 2100
30 73 152 285 590 890 1650
40 63 130 245 500 760 1450
50 56 115 215 440 670 1270
60 50 105 195 400 610 1150
70 46 96 180 370 560 1050
80 43 90 170 350 530 930
100 38 79 150 305 460 870
125 34 72 130 275 410 780
150 31 64 120 250 380 710
Table 12.2 - Gas Pipe Capacities - Natural Gas jk
j Capacities in cubic feet per hour through Schedule 40 pipe with maximum
0.3" W.C. pressure drop with up to 14" W.C. gas pressure. Specific gravity is
0.60 for natural gas and 1.50 for propane gas.
k For pipe capacity with propane gas, divide natural gas capacity by 1.6. Example:
What is the propane gas pipe capacity for 60' of 1-1/4" pipe? The natural gas
capacity is 400 CFH. Divide by 1.6 to get 250 CFH for propane gas.
WARNING
1. All field gas piping must be pressure/leak tested prior to
operation. Never use an open flame. Use a soap solution or
equilavent for testing.
2. Gas pressure to appliance controls must never exceed
14" W.C. (1/2 psi).
3. To reduce the opportunity for condensation, the minimum
sea level input to the appliance, as indicated on the serial
plate, must not be less than 5% below the rated input, or
5% below the minimum rated input of dual rated units.
CAUTION
1. Purging of air from gas lines should be performed as
described in ANSI Z223.1 - latest edition “National Fuel
Gas Code”, or in Canada CSA-B149 codes.
2. When leak testing the gas supply piping system, the
appliance and its combination gas control must be isolated
during any pressure testing in excess of 14" W.C. (1/2 psi).
3. The unit should be isolated from the gas supply piping
system by closing its field installed manual shut-off
valve. This manual shut-off valve should be located within
6' of the heater.
4. Turn off all gas before installing appliance.