Verifying the differential pressure establishes whether it is within the valve operating range. If the differential pressure is within the operating range (e.g. for Kombi-QM V5003TY10.., 160…2000mbar) the valve works properly and the flow rate will be kept at a constant set value.
Differential pressure gauging can however also be used to optimize pump efficiency. The pump delivery rate can be reduced on adversely positioned valves until just the required minimum pressure is available.