Overrun wiring

[mrscalex]

I'm wondering why boilers are fitted with 3 terminals to directly wire the pump when an overrun facility is present.

Why can't they just have a switched live terminal and the pump takes it's earth and neutral from the wiring centre?

Thanks,

Robert

 

[htgeng]

neatness and simplicity? One wire vs two?

 

[CH4]

It could also be that the effectiveness of the boiler's mains supply filter, intended to suppress electromagnetic interference, would be reduced if the pump's neutral and earth were taken from the wiring centre, as part of the filter would be bypassed.

 

[PEDANTICVINDICTIVEMAN]

Interesting, I have used the N & E in the wiring center rather than running two cables and use a 4 core to the boiler, never ever had any problems with the space time continuum on the boiler.

 

[CH4]

Very good PVM.

You shouldn't have any problems. It's the manufacturer that has to be seen to be conforming to the EMI emission requirements, set by yet another pile of EU directives.