Lochinvar SNA285-125 Manuale Utente

Pagina di 76
41
Nominal
Iron Pipe
Size (Inches)
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
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.
Table 6A 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.  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.
 WARNING
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. 
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 (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.
 WARNING
6  
Gas connections 
(continued)
  
 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.  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
TM