The E-RR power module lets you expand a heated floor zone beyond a single thermostat's 15A limit. It installs like a second thermostat but takes its signal from your existing DITRA-HEAT thermostat — one control point, multiple cable circuits.

• Connects to any DITRA-HEAT thermostat (E-R, E-RT, E-WiFi, E-RS1) via a low-voltage 20 AWG signal wire — when the thermostat calls for heat, the E-RR fires its cable circuit simultaneously
• Each E-RR handles one additional 15A circuit on its own dedicated breaker — add multiple modules for very large zones
• Built-in Class A GFCI — installs in a standard single-gang electrical box, requires its own dedicated electrical circuit

Pro tip: You'll need the E-RR when your heated area exceeds roughly 150 sq ft at 120V or 300 sq ft at 240V. Plan the extra circuit and box location during rough-in, not after drywall.