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The SMART ELECTRIC SE90340 is a double-pole double-throw (DPDT) relay designed for low-voltage control circuits operating on a 24-volt coil. DPDT relays switch two separate circuits simultaneously, making them a standard component in HVAC control systems where staging, reversing, or isolation of control signals is required. The SE90340 is sold as a single unit and is typically installed by licensed HVAC technicians or electricians during new system builds or control circuit repairs.
The SE90340 is suited for residential and light commercial HVAC applications where a 24-volt control circuit requires a DPDT switching configuration. Common install scenarios include thermostat control wiring, fan relay panels, and multi-stage equipment sequencing. Its double-pole double-throw design provides two independent switched paths, giving installers flexibility in control logic layout.
Designed as an OEM-style replacement for DPDT 24-volt relays used in residential and light commercial HVAC control circuit applications.
Installation is typically performed by a licensed HVAC technician or electrician. Always de-energize the control circuit and confirm voltage is absent before handling relay terminals. Verify coil voltage and contact rating against the existing circuit requirements before installation. Work should conform to applicable NEC requirements for low-voltage control wiring.
We pulled together the parts most installs need for this unit, plus a few add-ons worth a look. Check what you need — nothing here blocks checkout.
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