Bell & Gossett® has introduced Circuit Sentry™, an automatic flow limiting valve designed to adjust hydronic hvac systems to peak operating performance. Ideal for achieving optimal operation in variable speed pumping systems, the Circuit Sentry valve balances the system by compensating for hydronic pressure differences. It consists of a ball-type shutoff valve, commissioning measuring ports, and a flow control cartridge that maintains the flow rate at a constant level. The automatic flow rate cartridge ensures flow rate is maintained at a constant pressure, even under fluctuating pressure conditions, from as little as 2 psid to 60 psid, and maintaining the desired flow rate to +/-5%. The flow control cartridge also facilitates easy flushing of the piping upon commissioning of the system. Bell & Gossett.