i have one simple sealing unit.the input volt is 230V AC . used one step down tansformer and 4 number of heating element is series connection.first the input volt 23oVAC is given toTransformer primary and secondary 24VAC is connected to 4 numbers heating element in series connection.so i need to sepereted each heating element seperate switch . but i will try to connected 24vac to one element but its bunt. then try 2 element its also burnt so dont know how to seperated with switches .so i need your help .the input 230vac is connected simple domestic on/off switch with 3 pin plug top (6 amps) .