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Modulex Light Commericial Series
CHAPTER 4: Installation Instructions
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
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
Min. flow rate demanded in gal/min ∆T 27°F (15°C)
Min. flow rate demanded in gal/min ∆T 36°F (20°C)
Max flow rate demanded in gal/min ∆T 27°F (15°C)
Max flow rate demanded in gal/min ∆T 36°F (20°C)
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 4-19: 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. It becomes INDISPENSABLE if the system requires flow rates superior to the
maximum permitted boiler flow rates, which is to say lower than 27° F (15 K).
OMM-0087_J • GF-143 • 11/17/2020
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Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
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6.5
9.7
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4.9
7.3
9.7
22.6
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45.1
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33.9
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962
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14.6
17.0
56.4
67.7
79.0
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50.8
59.3
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1100
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Page 45 of 150
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