Grant On/Off Double Pole Switch (neon) EFBS19 Compatible with the following boilers: Grant Combi MKII Grant Combi V3 Grant Vortex Pro Kitchen/Utlity Condensing Standard & System Models. Grant Vortex Pro External Models. Grant Vortex Pro Condensing Combi Internal & External Models. Grant Vortex Eco Utility Condensing Standard & System Models. Grant Vortex Eco External Condensing Standard & System Models. Grant Vortex Eco Wall Hung Standard & System Models. Grant Euroflame Grant Multipass