HONEYWELL RA889A1001 120V, 60 Hz Switching Relay with Spdt switching. The RA889A Switching Relay with 24 V controller provides intermediate switching of line- and low-voltage devices from a line- or low-voltage controller and is typically applied in Hydronic heating systems. ? High load switching capability. ? Troubleshooting LED. ? Push-to-test button. ? Replaceable transformer fuse. ? Long-life DC relay drive control technology. ? Relay for use with external 24 Vac or 24 Vdc supply, with line-voltage control, or with internal 24 V transformer supply. ? One model replaces many Honeywell models. ? Secondary of transformer protected by replaceable 1A automotive fuse.