TROUBLESHOOTING NEXUS AUTOMATIC FLOW CONTROL VALVES

摘要

Environmental Test and Balance Company accepted a project balancing a condensing water system at a large educational facility for the Arkansas Army National Guard located in Little Rock. The referenced system consisted of 70 water source heat pumps served by system circulating pumps, a plate and frame heat exchanger, and a separate cooling tower loop. Each water source heat pump was furnished with a Nexus UltraMaticTM automatic flow control valve preset from the factory at a specified flow rate (GPM). The valve body houses a spring-loaded flow control cartridge that maintains a desired flow rate. The cartridge spring range is 2 to 45 PSID (0.14-3.10 Bar). The first number, 2 (0.14), of this spring range is the minimum differential pressure (DP) required to maintain constant flow and the second number, 45 (3.10), is the maximum DP the cartridge can absorb and still maintain the specified GPM.