Check Inlet Gas Supply - Lochinvar Shield SNR150-100 Installation & Service Manual

6
Gas connections
Table 6A Natural Gas Pipe Size Chart
Nominal
Iron Pipe
Size (Inches)
10 20
1/2 175 120
3/4 369 256
1 697 477
1-1/4 1400 974
1-1/2 2150 1500
2 4100 2820
2-1/2 6460 4460
3 11200 7900
4 23500 16100 13100 11100 10000
Shield water heaters are typically shipped ready to fire on natural gas. Check the water heater rating plate to
WARNING
determine which fuel the water heater is set for. In order to operate on LP gas contact the factory, 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.

Check inlet gas supply

CSA or UL listed flexible gas connections
NOTICE
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
WARNING
gas valve outlet pressure. The gas valve is
factory-set for the correct outlet pressure.
This setting is suitable for natural gas
and propane (when configured for LP),
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.
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. Disconnect power from the appliance.
2. Shut off gas to the appliance.
3. Loosen the set screw one (1) full turn from inside the
pressure tap on top of the gas valve. Place the tubing of
the manometer over the tap once the set screw is
loosened as shown in FIG.'s 6-4 thru 6-6.
4. Slowly turn on the gas supply at the field installed
manual gas valve.
(continued)
Natural Gas Pipe Capacity Chart
Length of Pipe in Straight Feet for 1/2 PSI
30 40 50 60
97 82 N/A N/A
205 174 155 141
384 328 292 267
789 677 595 543
1210 1020 923 830
2260 1950 1720 1560
3610 3100 2720 2460
6400 5400 4870 4410
9000
TM
70 80 90 100
N/A N/A N/A N/A
128 121 113 106
246 236 210 200
502 472 441 410
769 707 666 636
1440 1330 1250 1180
2310 2100 2000 1900
4000 3800 3540 3330
8300 7690 7380 6870
5. Reconnect power to the appliance.
6. Adjust the temperature set point on the control panel of
the electronic 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. Disconnect power from the appliance.
12. Shut off the gas to the appliance.
13. Remove the manometer from the pressure tap on top of
the gas valve. Re-tighten the set screw inside the pressure
tap.
When re-tightening the set screw, be sure to
WARNING
tighten securely to prevent gas leaks.
Do not check for gas leaks with an open
flame -- use the bubble test.
use the bubble test or check for gas leaks
can cause severe personal injury, death, or
substantial property damage.
14. Reconnect gas to the appliance.
15. Reconnect power to the appliance.
16. Adjust the temperature set point on the control panel of
the electronic control module to the desired water
temperature so the appliance will call for heat.
Installation & Service Manual
125 150 175
N/A N/A N/A
95 86 79
179 164 149
369 333 308
564 513 472
1100 974 871
1700 1540 1400
3000 2720 2500
6150 5640 5130
Failure to
200
N/A
74
138
287
441
820
1300
2340
4720
41