CH CYL STAT

[evdama]

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?

 

[seco services]

don't need earth

 

[kevplumb]

don't need earth

yer do or you would fall into oz

 

[seco services]

yer do or you would fall into oz

or end up in Tennessee

 

[kevindgas]

you need an Earth in the cable but not in the stat. (so run 3 core + earth)

wire exactly as the 2 diagrams show you and clip the earth wire at the stat (i turn it back annd clip it under the cable / cable clamp.)

 

[seco services]

you need an Earth in the cable but not in the stat. (so run 3 core + earth)

wire exactly as the 2 diagrams show you and clip the earth wire at the stat (i turn it back annd clip it under the cable / cable clamp.)

what do you gain out of that ?

 

[bengasman]

don't need earth

Not even a cpc?
How do you know that the impedance between cylinder and MET is below the max allowed?

 

[kevindgas]

you need an Earth in the cable but not in the stat. (so run 3 core + earth)

wire exactly as the 2 diagrams show you and clip the earth wire at the stat (i turn it back annd clip it under the cable / cable clamp.)

what do you gain out of that ?

when some **** cuts through the cable it trips the Mcb/Rcd that is why it is required otherwise you have 3 or 4 feet of unearthed cable.

 

[bengasman]

As the copper pipework and the HW tank is already copiously earthed ...

What makes you think the tank is earthed?

Tank cold in: not earthed.
Heating coil in and out; not earthed.
Hot water out; not earthed.
Tank itself; not earthed.

At least any and all cylinders I have seen.

 

[kevplumb]

yer do or you would fall into oz

or end up in Tennessee

yer could do worse

the waters up

i can fish off the deck in the front yard

the fridge is only 3 feet away

 

[evdama]

Im only assuming about the earthing,bengasman.Im following a hunch that all the earth bonding clamps might be doing something!

 

[kevplumb]

jeez ben

why aint we all dead

drank water out of lead pipes for long enough

it hasnt effectwed me

it hasnt effectwed me
it hasnt effectwed me

time 25 after 2

 

[kevindgas]

think you've drunk too much leaded water kev

 

[bengasman]

Im only assuming about the earthing,bengasman.Im following a hunch that all the earth bonding clamps might be doing something!

Very common mistake. No such thing as earth bonding. There is earhting, and bonding. The clamps you are referring to, are most likely for bonding, and although you might get a very good earth reading on them, they are not there too provide an earth.

It is a bit like dragging your mother in law behind your car with a rope around her neck; although she will slow the car down, she was not part of the designed braking system.

Regrettable as that might be in some cases.

 

[kevplumb]

ohh youve met her then