Replacing simple flick switch with timer on boiler

itnorfolk · Jul 29, 2012

Hey Guys,

I have a standard hot water boiler installed, and there is a standard switch to turn it on and off....

I want to replace this with a little 24h timer, enabling me to set it to come on and turn off....

I bought an LG-DIHT timer switch

On the rear the is quite simply AC, COM, then something that looks like WO or NO etc...

Inside my standard switch is:

the live, neutral and earth from the mains, and the boiler as a normal connection...

My question - What goes where? I'm assuming that AC is live in, COM is the grounds and the other connection is the boiler live and the earths are just joined in a block?

Any ideas?

steadyon · Jul 30, 2012

NO stands for Normally Open and NC stands for Normally Closed.

Assuming you don't have the instructions for the timer, I would expect the NO to have zero volts on its, going to 230V when the timer is "On".

I'd wire as follows:
Mains in: Live to AC, Neutral to COM, Earth to Earth.
Boiler Out: Live to NO, Neutral to COM and Earth to Earth.

mountainman · Jul 30, 2012

steadyon said:
NO stands for Normally Open and NC stands for Normally Closed.

Assuming you don't have the instructions for the timer, I would expect the NO to have zero volts on its, going to 230V when the timer is "On".

I'd wire as follows:
Mains in: Live to AC, Neutral to COM, Earth to Earth.
Boiler Out: Live to NO, Neutral to COM and Earth to Earth.