Navien NHB H Series Installation And Operation Manual page 22

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.
20°F ΔT @ 30% Glycol
Model
Flow Rate
(GPM)
NHB-055H 5.4
NHB-080H 7.8
NHB-110H 10.8
NHB-150H 14.5
Note
Do not exceed a maximum concentration of 35% glycol.
Minimum Flow Rates through the Boiler for Use with Glycol
Model
NHB-055H
NHB-080H
NHB-110H
NHB-150H
If the flow rate is below the required value for the specific boiler model as shown on the chart, it may
Note
result in noise and/or potential damage to the boiler.
22 Installing the System Piping
25°F ΔT @ 30% Glycol
Head Flow Rate
(Ft) (GPM)
10.0 4.3
20.2 6.3
15.2 8.6
27.4 11.6
Minimum Flow (GPM)
For use With 30% Glycol
35°F ΔT @ 30% Glycol
Head Flow Rate
(Ft) (GPM)
6.5 3.1
13.4 4.5
9.6 6.1
17.5 8.3
2.3
3.4
4.6
6.2
Head
(Ft)
3.5
7.0
4.8
9.0