Installation & Operation Manual
46
Nominal
Iron Pipe
Size (Inches)
Single Unit
Natural Gas Pipe Capacity Chart
Length of Pipe in Straight Feet for 1/2 PSI
10
20
30
40
50
60
70
80
90
100
125
150
175
200
1/2
175
120
97
82
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
3/4
369
256
205
174
155
141
128
121
113
106
95
86
79
74
1
697
477
384
328
292
267
246
236
210
200
179
164
149
138
1-1/4
1400
974
789
677
595
543
502
472
441
410
369
333
308
287
1-1/2
2150
1500
1210
1020
923
830
769
707
666
636
564
513
472
441
2
4100
2820
2260
1950
1720
1560
1440
1330
1250
1180
1100
974
871
820
2-1/2
6460
4460
3610
3100
2720
2460
2310
2100
2000
1900
1700
1540
1400
1300
3
11200
7900
6400
5400
4870
4410
4000
3800
3540
3330
3000
2720
2500
2340
4
23500
16100 13100 11100 10000
9000
8300
7690
7380
6870
6150
5640
5130
4720
Armor water heaters are typically shipped ready to fire on natural gas. Check the water heater rating plate to
determine which fuel the water heater is set for. If set to natural gas, it may be converted to LP by installing
an orifice or by making a gas valve adjustment (see pages 13 thru 15). In order to operate on LP gas, an orifice
MUST BE installed or a gas valve adjustment MUST BE made. Failure to comply could result in severe personal
injury, death, or substantial property damage.
Table 7A Natural Gas Pipe Size Chart
The gas piping must be sized for the proper flow 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., 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 151 - 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 flange to the valve and install a suitable 1/8"
(3 mm) fitting (field 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) fitting is installed
(depending on model) as shown in FIG.’s 7-6 thru 7-9 on
page
47.
4. Slowly turn on the gas supply at the field installed
manual gas valve.
WARNING
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 fires at
100% of rated input. Percent of burner input will be
displayed on the control panel.
8. Ensure inlet pressure is within specified range.
Minimum and maximum gas supply pressures are
specified 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, qualified 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 151 - 501 re-tighten the set
screw inside the pressure tap. On Models 601 - 801
remove the 1/8" (3 mm) field supplied fitting and
reinstall the pipe plug removed in Step 3.
Check inlet gas supply
NOTICE
CSA or UL listed flexible gas connections are
acceptable, but you must exercise caution to
ensure that the line has adequate capacity
to allow your water heater to fire at full
rate. Consult with local codes for proper
installation or service procedures.
DO NOT adjust or attempt to measure
gas valve outlet pressure. The gas valve is
factory-set for the correct outlet pressure.
This setting is suitable for natural gas and
propane, requiring no field adjustment.
Attempting to alter or measure the gas valve
outlet pressure could result in damage to
the valve, causing potential severe personal
injury, death, or substantial property damage.
WARNING
7
Gas connections
WARNING
When re-tightening the set screw, be sure to
tighten securely to prevent gas leaks.
Do not check for gas leaks with an open
flame -- use the bubble test. Failure to
use the bubble test or check for gas leaks
can cause severe personal injury, death, or
substantial property damage.
14. Turn on the gas supply at the manual gas valve.
15. Turn the power switch to the “ON” position.
16. Adjust the temperature set point on the control panel of
the SMART SYSTEM control module to the desired
water temperature so the appliance will call for heat.
