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INSTALLATION
Gas Connections
WARNING
1. All field gas piping must be pressure/leak tested prior to
operation. Never use an open flame. Use a soap solution or
equivalent 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 duel rated units.
CAUTION
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 codes.
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%.
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 CAN/CGA-B149.1 for
natural gas units and CAN/CGA-B149.2 for propane units.
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 8.1 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 8.2. 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 8.2 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. The gas piping to the unit can enter the unit from the side of
the unit or from below. Install a ground joint union with brass
seat and a manual shut-off valve external of the unit casing,
and 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 8.1).
4. Provide a sediment trap before each unit in the line where low
spots cannot be avoided. (See Figure 8.1).
5. 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.
8
Figure 8.1 - Recommended Sediment Trap/Manual
Shut-off Valve Installation - Side or Bottom Gas
Connection
j Manual shut-off valve is in the "OFF" position when handle is perpendicular
to pipe.
Table 8.1 - Burner Orifice Sizing and Gas Consumption
Model
Size
Cfh
75
Orifice Drill Size
Cfh
100
Orifice Drill Size
Cfh
125
Orifice Drill Size
Cfh
150
Orifice Drill Size
Cfh
175
Orifice Drill Size
Cfh
200
Orifice Drill Size
Cfh
225
Orifice Drill Size
Cfh
250
Orifice Drill Size
Cfh
300
Orifice Drill Size
Cfh
350
Orifice Drill Size
Cfh
400
Orifice Drill Size
j Based on natural gas properties of 1040 Btu/Cu. Ft. and specific gravity of 0.60.
k Based on propane gas properties of 2500 Btu/Cu. Ft. and specific gravity of 1.53.
Table 8.2 - Gas Pipe Capacities - Natural Gas j ‚
Pipe
Length (ft)
1/2"
10
132
20
92
30
73
40
63
50
56
60
50
70
46
80
43
100
38
125
34
150
31
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.
‚ For Pipe Capacity with Propane Gas, divide Natural gas capacity by 1.6. Example:
What is the Propane gas pipe capacity for 60 feet of 1-1/4" pipe? The Natural gas
capacity is 400 CFH. Divide by 1.6 to get 250 CFH for Propane gas.
5-564.4
j
Gas Type
Natural j
Propane k
72.1
30.0
20
39
96.1
40.0
30
45
120.2
50.0
25
42
144.2
60.0
30
45
168.3
70.0
27
43
192.3
80.0
23
42
216.3
90.0
20
39
240.4
100.0
25
42
288.7
120.0
20
39
336.5
140.0
27
43
384.6
160.0
23
42
Natural Gas
3/4"
1"
1-1/4"
1-1/2"
278
520
1050
1600
190
350
730
1100
152
285
590
890
130
245
500
760
115
215
440
670
105
195
400
610
96
180
370
560
90
170
350
530
79
150
305
460
72
130
275
410
64
120
250
380
Orifice Qty
1
2
2
3
3
3
3
4
4
6
6
2"
3050
2100
1650
1450
1270
1150
1050
930
870
780
710
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