Abstract: A direct return and reversed return chilled water system simulation network with bypass differential pressure control is established.By the method that shutting certain subcircuit, and computing hydraulic imbalance de-gree of other subcircuits, then the influence of the position of the differential pressure signal on the hydraulic stability of the system with on-off valves at the terminal is ana-lyzed.The result indicates that the farther away from the cold source, the worse the hydraulic stability of the system is as a whole, the closer the subcircuit to the position of pressure difference feedback signal,the better the stability, while the stronger the interference of the subcircuit is.So it's best to use the bypass loop as the signal taking posi-tion.When the pump frequency adjustment based on the temperature difference control is applied in the cold source side, the hydraulic stability of the pipe network significant-ly improved.

Key words: direct return, reversed return, bypass pressure difference control, hydraulic stability, position of differential pressure signal, temperature difference control