- Electronic Fuse – Auto reset
- Robust Transformer – Enough to handle up to 15 zones
- Double-sided printed circuit board construction
- 100% factory tested For reliability
- Clearly marked terminals with clamping plates
- Separate xx (isolated switch) & ZC/ZR Relays protect boiler aquastat
- Priority Safety Timer
- Ensures other zones get heat every 30 minutes & prevents freeze-ups
- 5-second Time Delay for boiler shut-off
- Relay Diagnostic Light
- Easily seen through window on cover
- Premium plug-in replaceable relays
- 24 VAC Transformer Terminals
- Plug-in, Add-on Zone Modules (AD-1 or AD-4)
- Switchable Priority
- High relay load rating – 1/3HP