Aquacal H/AT100R Owner's Manual And Installation Manual page 14

Plumbing Schematic–Flow Exceeding 70-GPM
CAUTION !
Failure to heed the following may result in damage to equipment.
Use of an incorrect bypass valve may compromise the heat pump's efficiency, reliability, and may void
the factory warranty. When using a bypass valve, order and install only an AquaCal PN: 2556 spring-
check bypass valve.
Bypass Check
Plumbing Schematics–Flow 70-GPM and Below
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