To Next PageTo Next Page
Need help?Do you have a question about the Taco SR506-5 and is the answer not in the manual?
The Taco SR506-5 Switching Relay is a six-zone control device designed for hydronic heating systems, capable of managing up to six thermostats and operating up to six zone circulators, in addition to two auxiliary outputs (AUX) for controlling other circulators like boiler and primary loops. This relay is engineered to enhance comfort levels and improve fuel efficiency in both modulating-condensing and conventional On/Off boiler systems, eliminating the need for an outdoor sensor through its energy-saving program.
The SR506-5 operates by energizing the appropriate circulating pump, illuminating a red light, and activating the boiler end switch relay and AUX circulator relay(s) whenever a thermostat calls for heat. It supports expansion connections, allowing up to 20 Taco zoning panels (SR and ZVC controls) to be daisy-chained, potentially managing up to 120 zones if all are six-zone panels. One switching relay is designated as the MASTER, controlling other daisy-chained EXPANSION zone controls via thermostat wire connections.
A key feature is the priority zone option, where zone 1 can be configured to operate exclusively during a priority call, deactivating zones 2 through 6. This is particularly useful for indirect water heater applications. To prevent prolonged priority calls from impacting other zones, a Priority Protection feature returns power to all other zones after one hour of continuous priority operation, allowing them to function independently until the priority zone is satisfied. The control then auto-resets, re-enabling priority for up to one hour from the next call.
The device includes several timing options to optimize system performance and longevity. Post Purge keeps the priority zone output energized for two minutes after its thermostat or aquastat is satisfied (without operating the boiler), ensuring residual heat is distributed. Pump Exercise cycles all attached circulating pumps for 30 seconds every two weeks, preventing seizing due to inactivity. Both Post Purge and Pump Exercise timings are adjustable via the eLink mobile app. A Low Limit (ZC) Operation feature stops all zone circulating pumps if the boiler temperature drops below a set low limit, and allows them to resume operation once the boiler rises above this limit.
The AUX 1 output is energized whenever any zone calls for heat, while AUX 2 (Primary Circulator Output) can be configured to energize with any zone call, except for the priority zone, depending on dip switch settings.
The SR506-5 also incorporates SmartPlus® Recirc Logic, an intelligent system that learns domestic hot water usage patterns. By recording daily hot water usage over a week via a pipe-mounted sensor, it automatically runs the circulator at corresponding times the following week, ensuring hot water availability. This system adapts to changes in usage patterns. In "Smart" Mode, it initially runs in "Pulse" mode for 7 days to learn patterns, then cycles the pump based on recorded usage. In "Pulse" Mode, it continuously cycles the circulator pump ON for 5 minutes and OFF for 10 minutes to maintain hot water. When a sensor is connected to the Recirc sensor input, zone 2 output is dedicated to DHW loop recirculation based on DHW usage.
General