The heating network circulating water pump system using D71 inverter has been put into operation for more than three years, and has achieved good economic and social benefits: 

• The control device operates reliably and has a low failure rate; 

• Through PID automatic adjustment, the phenomenon of uneven heating and cooling of each station in the heating network is eliminated; 

• Realize unmanned operation of production, greatly reduce labor intensity and improve production efficiency; 

• The economic benefits are significant, and all the increased investment can be recovered in more than one year.