Navien NHB Series, Руководство по установке и эксплуатации

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26 About the Boiler
Maximum and Minimum Flow Rates through the Boiler
Model Minimum Pipe Diameter Maximum Flow (GPM) Minimum Flow (GPM)
NFB-301C 1
1
/
4
" 32 10
NFB-399C 1 1 /
2
" 42 12
Temperature Rise Conditions
Model
20°F ΔT @ 100% water 25°F ΔT @ 100% water 35°F ΔT @ 100% water
Flow Rate (GPM) Head (Ft) Flow Rate (GPM) Head (Ft) Flow Rate (GPM) Head (Ft)
NFB-301C 29 10.5 24 7.4 17 4.0
NFB-399C 39 4.3 31 3.0 22 1.8
Pump Sizing for Use with Glycol
The use of glycol results in a greater head loss due to its higher viscosity compared to water. Heat transfer is also reduced as the glycol
concentration increases. The corrected flow rate and head loss values below must be used when sizing the boiler pump in order to maintain
similar performance as using 100% water for the heating system. Refer to the chart below.
Model
20°F ΔT @ 30% glycol 25°F ΔT @ 30% glycol 35°F ΔT @ 30% glycol
Flow Rate (GPM) Head (Ft) Flow Rate (GPM) Head (Ft) Flow Rate (GPM) Head (Ft)
NFB-301C 32 12.6 25 8.9 18 4.8
NFB-399C 42 5.2 33 3.6 24 2.2
Model
20°F ΔT @ 50% glycol 25°F ΔT @ 50% glycol 35°F ΔT @ 50% glycol
Flow Rate (GPM) Head (Ft) Flow Rate (GPM) Head (Ft) Flow Rate (GPM) Head (Ft)
NFB-301C 35 14.7 28 10.4 20 5.6
NFB-399C 46 6.0 37 4.2 26 2.5
Minimum Flow Rates through the Boiler for Use with Glycol
Model
Minimum Flow (GPM)
For Use With 30% glycol For Use With 50% glycol
NFB-301C 11 12
NFB-399C 13 14