Lochinvar SNA285-125, SNA500-125 Check inlet gas supply, Natural Gas Pipe Capacity Chart

TM

Installation & Service Manual

7Gas connections (continued)

Table 7A Natural Gas Pipe Size Chart

Nominal					Natural Gas Pipe Capacity Chart
Iron Pipe					Length of Pipe in Straight Feet for 1/2 PSI
Size (Inches)
	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

￿WARNING

Shield 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. 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

5. Reconnect power to the appliance.

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.

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.

￿WARNING

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 (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.

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

The gas piping must be sized for the proper flow and length of pipe, to avoid excessive pressure drop. Both the gas meter and

tap.

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.

￿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.

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 7-4 thru 7-6.
4.	Slowly turn on the gas supply at the field installed
	manual gas valve.

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.

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