Modulex Light Commercial Series
CHAPTER 4: Installation Instructions
OMM-0158_A
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4.15 Determination Of Primary Boiler Pump Or Boiler System Pump
The following table gives an indication of the pump’s flow rate in function of the
∆t
of the primary
circuit if the installation has a mixing header.
The size of the pumps must be determined by installers or technical engineers according to boiler
data and system design.
TABLE 4-2: MODULEX EXT Minimum/Maximum Flow Rates
BOILER MODEL
450 2S
600 2S
800 2S
1100 2S
Min. flow rate demanded in gal/min ∆T 27°F (15°C)
9.7
12.9
16.2
22.7
Min. flow rate demanded in gal/min ∆T 36°F (20°C)
7.3
9.7
12.1
17.0
Max flow rate demanded in gal/min ∆T 27°F (15°C)
33.8
45.1
56.4
79.0
Max flow rate demanded in gal/min ∆T 36°F (20°C)
25.4
33.9
42.3
59.3
The water side resistance curve of the boiler is shown in the diagram in Figure 4-19.
The pump is not an integral part of the boiler. It is recommended to choose a pump with the rate
and delivery head at about 2/3 of its characteristic heating curve.
Figure 4-17:
MODULEX EXT Water Side Pressure Losses
NOTE:
The use of a mixing header fitted between the boiler circuit and the system circuit is always
advisable. See Modulex EXT Piping Applications Guide TAG-0099 for additional details.
