GPA II series circulation motor pump is manily used in domestic heating and hot water system. The product is most applicable to the following systems. · Stable and variable-flow heat supply system ·Variable-temperature pipeline heat supply system · Heat supply system with night mode ·Domestic heating and domestic water supply system ·Industrial circulation system ·Solar system ·Air conditioning system Electronically controlled circulator pumps for domestic building and thermal solar systems. Shinhoo GPA II pumps are high-efficiency circulators, designed for heating and thermal solar systems. The ideal choice for basic functionality needs. Applicable as a universal upgrade and replacement pump. The pump features three constant-curve modes, proportional pressure curves, constant pressure curves, Auto and night mode. The speed can also be controlled by a low-voltage PWM signal from a controller to optimize the system performance.