17
Pipe Sizing for Gas Connection
These capacities shown below based on using SCH
40 black iron pipe. For capacities using other materials,
consult local code.
Maximum Equivalent Pipe Length (ft) (m)
Natural Gas 1000 BTU/FT
3
0.60
Specic Gravity @ 0.5 in WC Pressure Drop
Propane Gas 2500 BTU/FT
3
1.53
Specic Gravity @ 0.5 in WC Pressure Drop
Model
3/4" 1" 1-1/4" 1-1/2"
NAT PRO NAT PRO NAT PRO NAT PRO
206A
25
(7.6)
60
(18.3)
90
(27.4)
215
(65.5)
360
(109.7)
266/266A
15
(4.6)
35
(10.7)
50
(15.2)
125
(38.1)
210
(64.0)
480
(146.3)
445
(135.6)
336A
10
(3.0)
20
(6.1)
30
(9.1)
80
(24.4)
140
(42.7)
320
(97.5)
290
(88.4)
399/406A *
15
(4.6)
20
(6.1)
55
(16.8)
95
(29.0)
225
(68.6)
215
(65.5)
480
(146.3)
* A 3/4" gas line can be used for up to 5' (1.5 m) maximum length from the gas valve
in addition to the sediment trap.
Table K. Gas Pipe Sizing
Flow Rate
Model Pipe Size Min. GPM (lpm)
Max. GPM
(lpm)
206A 1-1/4"–1-1/2"–2" 20 (75) 100 (378)
266/266A 1-1/4"–1-1/2"–2" 25 (95) 100 (378)
336A 1-1/4"–1-1/2"–2" 35 (132) 100 (378)
399/406A 1-1/4"–1-1/2"–2" 40 (151) 100 (378)
* When ow rates exceed maximum GPM an external auxiliary bypass valve is
required. See external bypass valve section for details.
Table L. Min/Max Flow Rates
INLET
OUTLET
Figure 19. Polymer Header Water Flow
F10637-1
INLET
OUTLET
Figure 20. Bronze Header (ASME) Water Flow
Flow GPM
(lpm)
Pressure Drop (Ft. of Head) (m of Head)
206A 266/266A 336A 399/406A
20 (75) 4.0 (1.2)
25 (95) 4.0 (1.2) 4.6 (1.4)
30 (113) 4.0 (1.2) 5.2 (1.6)
35(132) 4.0 (1.2) 5.8 (1.8) 5.2 (1.6)
40 (151) 4.6 (1.4) 5.8 (1.8) 5.2 (1.6) 5.2 (1.6)
50 (189) 4.6 (1.4) 6.3 (1.9) 6.9 (2.1) 6.9 (2.1)
60 (227) 4.6 (1.4) 6.9 (2.1) 6.9 (2.1) 6.9 (2.1)
70 (265) 4.6 (1.4) 8.1 (2.5) 9.2 (2.8) 9.2 (2.8)
80 (303) 4.6 (1.4) 9.2 (2.8) 9.8 (3.0) 9.8 (3.0)
90 (340) 6.9 (2.1) 10.4 (3.2) 10.4 (3.2) 10.4 (3.2)
100 (378) 8.1 (2.5) 11.0 (3.4) 12.1 (3.7) 12.1 (3.7)
Table M. Polymer Heat Exchanger Pressure Drop -
Residential Models - (UG Fully Open)
PRELIMINARY
UNCONTROLLED DOCUMENT IF PRINTED