Immersion heater timer query

[pinkynotthebrain]

Hi, looking for some advice, I currently have an immersion heater which is run either by 24hr electric, ie no timer, or by a timer that links to our oil fired system.
Currently the mains goes to a 20a double pole switch, from this the main wire then goes directly to the immersion heater, but also from the 20a switch,they're is another connection to an isolator switch which goes down to the timer for the oil fired system.
This is fine if I'm happy to run off the oil, but is there also a way to install a timer for the electric side of it. On most systems you would wire this inbetween the pole and the immersion heater, but would this then override the oil heated timer.
Hope that makes sense.

 

[EFLImpudence]

Yes

I'm not clear from your description of the set-up but -

It won't override the boiler if you wire it so that it does not.
However, you may not want both to be on together.

 

[pinkynotthebrain]

Try again with the description. I have the mains going into the 20a socket. Live to L1, Neutral to N1 and earth is earthed . From L1 and N1, wiring going into a isolator switch which goes to Load L and Load N. Again earthed.
From here, wiring goes down to timer for oil system, via live and N Supply.
Also in the 20a switch is the live and neutral to the immersion heater which goes from the L2 and N2, again earthed.

 

[pinkynotthebrain]

 

[EFLImpudence]

Still not 100% sure of wiring, however -

You can get a timer, as in the link above, and wire it in the immersion cable where it will not affect anything else.

I do not understand why you want a timer on the immersion when there is a timer on the boiler.
Surely you only want/need the immersion if the boiler should fail.

I would think it just needs separate switches for the immersion and boiler.

 

[pinkynotthebrain]

It's because the immersion heater runs from the electric and the oil system together, which is fine when the oil prices are low as this is cheaper so I can use the oil to heat the water. When its not cheaper I use the electric, but there is no way to time the electric, hence the query.

 

[EFLImpudence]

The immersion heater is just a big kettle; it does not run from the oil system.

They are completely separate therefore you need to connect the immersion timer into the immersion cable.

 

[endecotp]

It's because the immersion heater runs from the electric and the oil system together

No, you need to get the terminology right or people will just get confused. The hot water cylinder runs from either an electric immersion heater or from the oil boiler.

which is fine when the oil prices are low as this is cheaper so I can use the oil to heat the water. When its not cheaper I use the electric, but there is no way to time the electric, hence the query.

Yes, you can fit a timer.

 

[pinkynotthebrain]

Oops, my mistake no intention to confuse anyone. I can either heat the hot water cylinder through the oil boiler or can use the electric to heat it. The immersion heater is connected to the top of the hot water tank in the normal way and wired as described.
So when the timer for the oil to heat the water is turned off, the water is heated by electric if the 20a switch is turned on.
So it's sound like I need to put the timer in-between the 20a switch and the immersion heater

 

[endecotp]

Yes, that sounds right.

Are you considering doing this yourself?

 

[pinkynotthebrain]

That was the plan, just really double checking what I thought was the case. Thanks to everyone for their help

 

[kai]

You appear to have an incorrectly wired set up - the proper way, as per the photo, is to have separated feeds for both the immersion heater, and gas boiler, allowing independent switching of each item, without affecting the other - ideally fed from separate circuits.
You can see there are two fused spur units, one for the Immersion, and the other for the Boiler above.

 

[ericmark]

If you set the thermostats then there is no need for a timer. The idea is oil heats water to say 80°C and electric set to 65°C so with a well insulated tank oil will do all the heating unless you run a bath then electric will cut in as well to reheat the tank. This was standard with many systems I found out the hard way my daughters house she wanted cooler water at the taps so I reduced the temperature on the tank stat result was large electric bill when electric cut in instead. 65°C is considered minimum setting to stop legionnaires.

You can fit a timer on electric but if set low on thermostat not really required.

 

[ban-all-sheds]

https://farm6.staticflickr.com/5187/5649269101_0553c87bab.jpg

What's the point of all those caution and danger notices?

 

[riveralt]

https://farm6.staticflickr.com/5187/5649269101_0553c87bab.jpg

What's the point of all those caution and danger notices?

I don't know - maybe death - danger - lurking - behind those white boxes!!!!
The more the merrier as far as I am concerned.