A use for a contactor?

[lummocks]

I understand relays..and their uses...I'm hoping you can help me with this so bear with me.

I'm looking to turn a water boiler on when the lights in my garage come on, basically so its not left on overnight. The lights are always switched off when I leave and on when I enter despite the time of day.

I'm not sure if i'm barking up the wrong tree but is this the kind of time i'd use a contactor?

As in wire in the contactor to the lighting live so it picks the contactor and switches both poles of a fused spur to the water boiler?

Can anyone recommend one for this application. Think the water boiler is 2.5k

Thanks in advance

 

[ColJack]

an immersion heater timer is going to be much more practical and probably cheaper than a contactor...

either way, yes you can use a contactor to do what you ask.. but you'll neeed a neutral too.. not just a switched live..

 

[JohnD]

another method is to use an Immersion Heater Timer with Pins for switching. Put all the Pins in the "off" ring and use the override switch to turn it on when you want it.

edited: too slow

 

[lummocks]

Thanks guys

 

[seasickstevie]

Don't understand the timeswitch suggestion JohnD.

Surely it's just going to switch off shortly after being switched on every time.
Or am I reading it wrong?

 

[ColJack]

depending on the type, it will either click off the next time the clock "ticks" round a notch, or it will stay on until you turn it off..

 

[seasickstevie]

If the latter, may as well use a 'switch'

 

[ColJack]

no ones asked the relevant questions yet so I might as well...

what's the water boiler used for?
how long and how often are you in the garage for?
why don't you want it left on overnight? cost?


now for the silly questions..

does your garage have a sunny roof? is yes have you considered a solar heating solution.. it'll switch off at night I promise

 

[JohnD]

Don't understand the timeswitch suggestion JohnD.

Surely it's just going to switch off shortly after being switched on every time.
Or am I reading it wrong?

you insert some "off" pins at times to suit yourself

e.g. 4pm, 6pm, 10pm

at about the time you usually leave, but with some extra ones in case you work late

you do not have to insert an "on" pin unless you almost always arrive at about the same time.

 

[ericmark]

A standard relay will handle 12A per set of contacts so using both sets would likely handle the load without using a contactor. The problem is most relays and contactors will also need some sort of box

Hagar do make relays to fit inside a consumer unit

Which may be better is you have room or fit in a garage consumer unit box.

I do understand the problem so easy to boil dry if left on. On the Falkland I had ours on a change over switch and once boiled I ran on 110v which just kept it on a simmer and I piped the steam into a carboy and it also provided distilled water for topping up batteries.

That was until they found a still in one section and hunted for any more and it seems they couldn't smell the difference between distilled water and potatoes?

After which it was replaced with a "Hot Tap" which was a boiler with loads of plates in it to stop the water circulating and a ball valve which re-filled it from mains as boiling water was drawn. This worked very well even when a dozen lads all came for a cupa together the boiling water never seemed to run out although I am sure if you had 2 dozen lads my be different story.

The boiling water at bottom heated cold water coming in at top and the baffles stopped it cooling the water at bottom to under boiling and it also heated up a lot quicker in morning.

 

[Steve]

eric, im sure his water heater has a thermostat so it doesn't boil . . .