2 Ways DR3602 Dual Relay Pressure Switch Transformed Dual Setpoint
Why Calendar-Based Filter Changes Cost Us $25,000 Annually
Our tank farm was experiencing frequent overflow incidents. The float sensor read full, but the pump kept running, causing waste and delays. Upon investigation, we discovered that the pressure drop across the filter was creeping up, but the calendar said it wasn’t time for change. This discrepancy led to undetected filter clogging, which in turn caused the pump to run longer than necessary, eventually leading to overflows. As a result, we faced annual waste disposal costs exceeding $25,000 and significant downtime.
Calendar Days vs Pressure Drop: The $25,000 Difference
The root cause was a fundamental limitation of single-relay switches: they cannot provide both high and low alarm protection simultaneously. Consequently, our setup failed to detect the critical pressure drop in a timely manner. In engineering terms, we needed a device that could independently monitor two distinct thresholds: one for high pressure (to stop the pump) and one for low pressure (to start the pump). Without this dual-setpoint capability, we were essentially blind to the gradual pressure increase caused by filter fouling. Moreover, relying on a fixed maintenance schedule ignored the actual operating conditions, leading to either premature filter changes (waste) or delayed changes (overflows).
How DR3602 Solved Our Dual Setpoint Control Challenge
We installed the DR3602 dual relay pressure switch, which offers two independent relays for high and low alarm settings. This setup allowed us to set precise thresholds for when the pump should start and stop based on actual pressure changes rather than calendar-based maintenance schedules. Specifically, we programmed the low relay to start the pump at a pressure drop of 2 bar and the high relay to stop the pump at a pressure drop of 5 bar. Additionally, the programmable hysteresis prevented rapid cycling. The 4-digit LED display provided real-time pressure readings, and the optional 4-20mA analog output enabled integration with our SCADA system. The NEMA 4X / IP65 enclosure ensured durability in the harsh tank farm environment.
Why Did Our Overflow Incidents Drop by 85%?
The installation immediately paid off: we reduced overflow incidents by 85%, saving over $20,000 in waste disposal costs annually. The dual relays also improved our pump control efficiency, reducing downtime by 30%. Furthermore, the RS485 output allowed remote monitoring, enabling proactive maintenance. In fact, we now change filters based on actual pressure drop, not a calendar. This approach has eliminated unnecessary filter changes and prevented overflows entirely.
Key Specifications
- Dual independent relays for high/low alarm
- Programmable setpoints and hysteresis
- 4-digit LED display
- 4-20mA analog output optional
- RS485 output optional
- 24VDC powered
- NEMA 4X / IP65 enclosure
How have you managed pressure monitoring in your tank farm? Are you still relying on single-relay switches or calendar-based maintenance? Consider upgrading to a dual relay pressure switch like the DR3602 to achieve similar savings and reliability.
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Tags: #dualrelaypressureswitch #highlowalarm #pumpcontrolpressureswitch #DR3602
