I have a control pack that contadicts itself.
The diagram for the cylinder stat shows three teminals - call,sat and common.Ther are no other terminals on the diagram or the stat itself.
The wiring centre however has four wires for the cyl stat - that fourth one being an earth symbol.
As the copper pipework and the HW tank is already copiously earthed ,should I need to run a four core cable or could I just use a three core?
The diagram for the cylinder stat shows three teminals - call,sat and common.Ther are no other terminals on the diagram or the stat itself.
The wiring centre however has four wires for the cyl stat - that fourth one being an earth symbol.
As the copper pipework and the HW tank is already copiously earthed ,should I need to run a four core cable or could I just use a three core?