How many wires to the hot water tank?

[GSUK]

Hi,

I have an old Servowarm boiler and a mechanical lever by the HWT for switching between "heating\hot water" or just "hot water". I'm looking to have it replaced later in the year but to keep costs down I will run the necessary cables between the boiler and the tank. Question is how many cores does the flex need for a fully automated valve, plus a thermostat on the HWT.

Looking at whats there I reckon a 3port valve will fit. Its a fully pumped open vented system (if that helps)

Also, is 0.5mm flex heavy enough? I'm assuming yes as there is no load on the flex other than a small motor in the valve.

Thanks very much in advance,
Glenn

 

[Whitespirit66]

5 core for a 3-port mid position valve. HW cylinder stats need 3 cores.

I usually use .75mm heat-resistant cable.

You can probably get it by the metre from an electrical suppliers, rather than the 50 metre coils from Screwfix, etc.

 

[GSUK]

Great!

Thanks very much