48
7
Gas connections
Table 7A Natural Gas Pipe Size Chart
Th
e gas piping must be sized for the proper fl ow and length of
pipe, to avoid excessive pressure drop. Both the gas meter and
the gas regulator must be properly sized for the total gas load.
If you experience a pressure drop greater than 1 inch w.c.
(249 Pa), the meter, regulator, or gas line is undersized or in
need of service. Perform the steps below when checking inlet
gas supply:
1. Turn the main power switch to the “OFF” position.
2. Shut
off gas supply at the manual gas valve in the gas
piping to the appliance.
3. On Models 400 - 501 loosen the set screw one (1) full turn
from inside the pressure tap on top of the gas valve. On
Models 601 - 801 remove the 1/8" (3 mm) pipe plug on the
inlet
fl ange to the valve and install a suitable 1/8" (3 mm)
fi tting (fi eld supplied) for the manometer tubing. Place
the tubing of the manometer over the tap once the set
screw is loosened or the 1/8" (3 mm) fi tting is installed
(depending on model) as shown in FIG.’s 7-5 thru 7-7 on
page
49.
4. Slowly turn on the gas supply at the fi eld installed
manual gas valve.
5. Turn the power switch to the “ON” position.
6. Adjust the temperature set point on the control panel of
the SMART SYSTEM control module to call for heat.
7. Observe the gas supply pressure as the burner fi res at
100% of rated input. Percent of burner input will be
displayed on the control panel.
8. Ensure inlet pressure is within specifi ed range.
Minimum and maximum gas supply pressures are
specifi ed in this section of the manual.
9. If gas supply pressure is within normal range and no
adjustments are needed, proceed on to Step 11.
10. If the gas pressure is out of range, contact the gas utility,
gas supplier, qualifi ed installer or service agency to
determine the necessary steps to provide proper gas
pressure to the control.
11. Turn the power switch to the “OFF” position.
12. Shut off the gas supply at the manual gas valve in the gas
piping to the appliance.
13. Remove the manometer from the pressure tap on top of
the gas valve. On Models 400 - 501 re-tighten the set
screw inside the pressure tap. On Models 601 - 801
remove the 1/8" (3 mm) fi eld supplied fi tting and
reinstall the pipe plug removed in Step 3.
Check inlet gas supply
NOTICE
CSA or UL listed fl exible gas connections
are acceptable, but you must exercise
caution to ensure that the line has adequate
capacity to allow your boiler to fi re at full
rate. Consult with local codes for proper
installation or service procedures.
DO NOT adjust gas valve outlet pressure.
Attempting to alter the gas valve outlet
pressure could result in damage to the valve,
causing potential severe personal injury,
death, or substantial property damage.
WARNING
Installation & Operation Manual
Capacity of Schedule 40 Metallic Pipe in Cubic Feet of Natural Gas Per Hour
(based on .60 specifi c gravity, 0.30" w.c. pressure drop)
Pipe
Size
(Inches)
Length of Pipe in Straight Feet
10
20
30
40
50
60
70
80
90
100
125
150
175
200
1/2
131
90
72
62
55
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
3/4
273
188
151
129
114
104
95
89
83
79
70
63
58
N/A
1
514
353
284
243
215
195
179
167
157
148
131
119
109
102
1 1/4
1,060
726
583
499
442
400
368
343
322
304
269
244
224
209
1 1/2
1,580
1,090
873
747
662
600
552
514
482
455
403
366
336
313
2
3,050
2,090
1,680
1,440
1,280
1,160
1,060
989
928
877
777
704
648
602
2 1/2
4,860
3,340
2,680
2,290
2,030
1,840
1,690
1,580
1,480
1,400
1,240
1,120
1,030
960
3
8,580
5,900
4,740
4,050
3,590
3,260
3,000
2,790
2,610
2,470
2,190
1,980
1,820
1,700
4
17,500 12,000
9,660
8,270
7,330
6,640
6,110
5,680
5,330
5,040
4,460
4,050
3,720
3,460
