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Table 11. Boiler Flow and Head Requirements
4.B Boiler Water Flow & Headloss Data
See Table 11 for water flow and boiler headloss, based on heat exchanger temperature rise.
4.C
Water Heater Water Flow and Headloss Data
Water flow and headloss for water heaters is based on the water’s hardness, to help minimize scale (mineral) buildup
inside the heater’s water tubes. Table 12 shows water flow and headloss based on the hardness of the system’s
water. Temperature rise is shown for information and testing/troubleshooting purposes.
Table 12. Volume Water Flow Rates
Model
20°F
25°F
30°F
35°F
40°F
Flow
gpm
Headloss
ft
Flow
gpm
Headloss
ft
Flow
gpm
Headloss
ft
Flow
gpm
Headloss
ft
Flow
gpm
Headloss
ft
1250
110
25.0
88
16.4
73
11.5
63
8.6
55
6.6
1500
131
34.8
105
22.9
87
16.0
75
12.1
65
9.1
1750
152
19.5
122
13.4
102
9.4
87
6.4
76
4.2
2000
176
24.9
140
16.6
117
11.8
100
8.5
88
6.2
2500
219
36.1
175
24.7
146
17.9
125
13.4
110
10.4
3000
259
65.2
207
40.7
173
28.1
148
20.4
129
15.6
Model
11°C
14°C
17°C
19°C
22°C
Flow l/m
Headloss
m
Flow l/m
Headloss
m
Flow l/m
Headloss
m
Flow l/m
Headloss
m
Flow l/m
Headloss
m
1250
416
7.6
333
5.0
276
3.5
238
2.6
208
2.0
1500
496
10.6
397
7.0
329
4.9
284
3.7
246
2.8
1750
575
5.9
462
4.1
386
2.9
329
2.0
288
1.3
2000
666
7.6
530
5.1
443
3.6
379
2.6
333
1.9
2500
829
11.0
662
7.5
553
5.5
473
4.1
416
3.2
3000
980
19.9
784
12.4
655
8.6
560
6.2
488
4.8
*Headloss is for the heater only (no piping) Allowable pH is 6.5 to 9.5
Model
1 - 10 Grains Per Gallon Hardenss
11 - 15 Grains Per Gallon Hardness
Flow Rate
(gpm)
Headloss* (ft)
Temp Rise (°F)
Flow Rate
(gpm)
Headloss* (ft)
Temp Rise (°F)
1250
85
16.1
26
104
23.6
21
1500
90
17.9
29
110
26.3
24
1750
120
12.9
25
150
19.6
20
2000
135
16.1
26
170
24.4
21
2500
140
17.2
31
170
24.4
26
3000
150
21.0
35
183
31.5
28
Model
1 - 10 Grains Per Gallon Hardenss
11 - 15 Grains Per Gallon Hardness
Flow Rate (l/m)
Headloss* (m)
Temp Rise (°C)
Flow Rate (l/m)
Headloss* (m)
Temp Rise (°C)
1250
322
4.9
14
394
7.2
12
1500
341
5.5
16
416
8.0
13
1750
454
3.9
14
568
6.0
11
2000
511
4.9
14
644
7.4
11
2500
530
5.2
17
644
7.4
14
3000
568
6.4
19
693
9.6
16
