Takagi T-H3J-DV Installation Manual And Owner's Manual page 24

Maximum delivery Capacity of Cubic Feet of Gas per Hour of IPS Pipe carrying Natural Gas with 0.60 Specific Gravity
Based on Pressure Drop of 0.5" W.C.
Based on Energy Content of 1,000 BTU/Cubic ft.: The water heater requires 160 Cubic ft./hr for the 240 (T-H3J)
models, 180 Cubic ft./hr for the 340 (T-H3S) models, and 199 Cubic ft./hr for the 540 (T-H3) models.
Pipe Size
Diameter 10' 20'
363 249
3/4"
1" 684 470
1 1,404 965
1/4"
1 2,103 1,445 1,161 993
1/2"
2" 4,050 2,784 2,235 1,913 1,696 1,536 1,413 1,315 1,234 1,165 1,033 936
Maximum Capacity of Propane (LP) Based on 11" W.C. supply pressure at a 0.5" W.C. pressure drop
Pipe Size
Diameter 10' 20'
567 393
3/4"
1" 1,071 732
1 2,205 1,496 1,212 1,039 913
1/4"
1 3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976
1/2"
2" 6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496 1,260
Gas sizing example
(Natural Gas)
Based on Energy Content of 1,000 BTU/Cubic ft:
Divide each appliance's BTU requirement by 1,000 BTU/h to get the appliances Cubic Ft. requirement.
Take into account the distance the appliance is from the gas meter, look in the above gas chart to properly size the line.
For sections of the gas line supplying gas to more than one appliance (Ex: Point A to Point B), add up the cubic ft.
requirements of the appliances that are being supplied by that section, and size to the farthest appliance.
For Example: The section from A to B supplies gas to the furnace, range and dryer. Adding up the BTU requirements and
dividing by 1,000 yields a cubic ft. requirement of 220 cubic ft. of gas. The farthest appliance is the range, which is 50 ft.
away from the meter. Looking at the above chart, and under the column of 50 ft., Section A to B needs to be 1" in order
to supply 220 cubic ft.
-Natural Gas Supply Piping-
30' 40' 50' 60'
200 171 152 138
377 323 286 259
775 663 588 532
880 798
-Propane (LP) Supply Piping-
30' 40' 50' 60'
315 267 237 217
590 504 448 409
834
Water
heater
199,000 BTU/h
10' Length
3/4" Pipe size
5' Length
1-1/4" Pipe size
A
10' Length
1" Pipe size
5' Length
1-1/4" Pipe size
Gas meter
24
Length
70' 80' 90' 100'
127 118 111 104
239 222 208 197
490 456 428 404
734 683 641 605
Length
70' 80' 90' 100'
196 185 173 162
378 346 322 307
771 724 677 630
35,000 BTU/h
15' Length
B
1" Pipe size
10' Length
3/4" Pipe size
Furnace
Range
120,000 BTU/h
65,000 BTU/h
Page
Installation Manual
Installation
Unit: Cubic feet per hour
125' 150' 200'
93 84 72
174 158 135
358 324 278
536 486 416
801
Unit: kBTU per hour
125' 150' 200'
146 132 112
275 252 213
567 511 440
866 787 675
Dryer
10' Length
1/2" Pipe size
15' Length
1/2" Pipe size
C