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PN 240012960 REV. F [09/15/2020]
CH Circuit
• Piping diameter shall not be reduced from the DHW module’s provided 3/4" connection size.
• Piping to and from the boiler should be kept as short as possible with minimum number of restrictions such as
elbows in order to maximize CH flow and DHW output.
•
Increasing CH pipe diameter to boiler to 1" may be beneficial in reducing pressure drop in the connecting piping,
further increasing CH flow. This could be helpful if the DHW module is far away from the boiler.
• To simplify air purging, a purge valve may be installed in the CH circuit. In order to purge air the DHW module must
be powered and have domestic water flowing in order to open the two way valve and allow CH flow to purge air out
of the flat plate heat exchanger.
• Charts below show the pressure drop through the CH circuit of the DHW module, and the remaining available pump
head for connecting piping after accounting for that pressure drop.
CH Circuit Pressure Drop versus Flow Rate Through
DHW Module
PHE22-MAX represents the pressure drop with the motor at minimum stroke tolerance.
PHE22-MIN represents the pressure drop with the motor at maximum stroke tolerance.
CH Circuit Available Pump Head for
Connecting Piping