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
Specific Gravity @ 0.5 in WC Pressure Drop
Propane Gas 2500 BTU/FT
3
1.53
Specific 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 flow rates exceed maximum GPM an external auxiliary bypass valve is
required. See external bypass valve section for details.
Table L. Min/Max Flow Rates
F10638-1
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
