Check Inlet Gas Supply - Lochinvar WH 55-399 Installation & Operation Manual

7
Gas connections
Table 7A 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
Knight wall mount boilers are typically shipped ready to fire on natural gas. Check boiler rating plate to
WARNING
determine which fuel the boiler is set for. If set to natural gas, it may be converted to LP by installing an
orifice (see page 13). In order to operate on LP gas, an orifice MUST BE installed. 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 boiler
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.
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.
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. Shut off power at source.
2. Shut off gas supply at the manual gas valve in the gas
piping to the appliance.
50
Natural Gas Pipe Capacity Chart
Length of Pipe in Straight Feet for 1/2 PSI
30 40 50
97 82 N/A
205 174 155
384 328 292
789 677 595
1210 1020 923
2260 1950 1720 1560
3610 3100 2720 2460
6400 5400 4870 4410
9000
This setting is suitable for
Installation & Operation Manual
60 70 80 90
N/A N/A N/A N/A
141 128 121 113
267 246 236 210
543 502 472 441
830 769 707 666
1440 1330 1250
2310 2100 2000
4000 3800 3540
8300 7690 7380
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. 7-3.
4. Slowly turn on the gas supply at the field installed
manual gas valve.
5. Turn on power at source..
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. Shut off power at source.
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. Re-tighten the set screw inside the pressure
tap.
100 125 150 175
N/A N/A N/A N/A
106 95 86 79
200 179 164 149
410 369 333 308
636 564 513 472
1180 1100 974 871
1900 1700 1540 1400 1300
3330 3000 2720 2500 2340
6870 6150 5640 5130 4720
200
N/A
74
138
287
441
820