9
76683
NOTE: To determine the size of the branch gas line from the main gas line to the fireplace, enter the tables below (for iron
pipe or copper tubing) using the distance from the gas meter or second stage regulator to the furthest appliance on the
gas system. Select a pipe or tube diameter which has enough capacity to meet the maximum input requirement of the
fireplace. Regardless, do not use less than 1/2" diameter for the branch line. For any distances required longer than
shown in these tables, refer to the National Fuel Gas Code.
NOTE: There may be a local gas utility requirement specifying a minimum diameter for gas piping. All units require a 1/2 inch pipe
connection at the gas valve.
Gas Line Pipe Sizing
CAPACITY OF PIPING
Cubic Feet per Hour based on 0.3" w.c. Pressure Drop
Specific Gravity for Natural Gas - 0.6 (1000 BTU/Cubic Foot)
Specific Gravity for Propane Gas - 1.6 (2550 BTU/Cubic Foot)
Length
Nominal Inches for Iron Pipe Sizes (1,000s BTU/hr)
of
1/2” D
3/4” D
1” D
1
¹⁄₄
” D
1
¹⁄₂
” D
Pipe
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
Natural
Propane
20’
92
143
190
296
350
546
730
1135
1100
1711
30’
73
115
152
237
285
444
590
918
890
1385
40’
63
97
130
202
245
380
500
778
760
1183
50’
56
87
115
179
215
334
440
683
670
1043
60’
50
79
105
163
196
304
400
622
610
949
70’
46
71
96
151
180
280
370
576
560
872
90’
40
61
84
130
160
250
320
497
490
763
100’
38
59
79
122
150
235
305
474
460
717
Outside Diameter Copper Tubing, Type L (1,000s BTU/hr)
Tubing Length
1/2”
5/8”
3/4”
7/8”
Feet
0.43
0.545
0.666
0.785
10
110
206
348
536
20
76
141
239
368
30
61
114
192
296
40
52
97
164
256
50
46
86
146
224
60
42
78
132
203
80
36
67
113
174
100
32
59
100
154
WARNING: Use only internally tinned copper tubing. If correct copper tubing is not used, tubing can deteriorate and develop
gas leaks.
Table 1
Gas Inlet Pressure
Natural
Propane
Max.
14.0” w.c.
14.0” w.c.
Normal
7.0” w.c.
11.0” w.c.
Min.*
5.0” w.c.
10.8” w.c.
Regulator Pressure
3.5” w.c.
10.0” w.c.
*Minimum inlet supply pressure for the purpose of input adjustment.
Gas Pressure Check
The gas inlet pressure specified in Table 1 is the pressure
where the field-installed gas line connects to the gas control.
This is measured at the inlet test port on the gas valve in the
appliance. Ensure that pressure is as shown in Table 1.
The manifold pressure is controlled by the gas valve and should
be checked at the pressure test points as shown in Figure 9 on
Page 11. The pressure connections accept 1/4” I.D. hose or
tubing.
The pressure should be checked with the appliance burning on
high (highest setting) and all other appliances turned on. One
must then read the manometer and if pressures are not 10.0”
w.c. for LP or 3.5” w.c. for Natural gas the inlet pressure must
be adjusted or increased until the proper pressures are at-
tained. If these pressures are greater than 10.2” w.c. for LP or
3.7” w.c. for Natural gas, contact your gas supplier before
operating the appliance.
Pressure is tested by loosening (do not remove) the screw in
the test port and sliding tubing onto the test port.
CAUTION: If the appliance's operating pressures are not
checked and adjusted, improper combustion may result in
soot being produced. Record the results of the gas
pressure check on the appropriate documents.
Testing the Gas Piping.
Test all piping for leaks. When
checking gas piping to the heater with gas pressure less than
1/2 psi, shut off manual gas valve for the heater. If gas piping is
to be checked with the pressure at or above 1/2 psi, the heater
and manual shut off valve must be disconnected during testing
to prevent damage to the regulator on the unit. (SEE WARN-
ING).
To ensure that the gas lines and connections do not have any
leaks, a pressure test should be performed. Only a qualified
installer should perform the pressure test to ensure that
the unit is not damaged by high pressures!
WARNING: Be sure that the gas type indicated on the
gas log rating plate concurs with the gas system in your
building.
