can anyone get me out of a hole. on a job at moment with vaillant ecotec system boiler ,honeywell s plan for rads and cylinder and polyplumb underfloor heating system.all wired up ok apart from when switch live on s plan are both in terminal 4 on boiler it trips rcd on house consumer unit.both run fine seperatly but together power is sent down ufh switch live cable to wiring center on uhf tripping it out.help please