My daughter wants a timer fitting to her immersion heater to make better use of Economy 7.
Have looked on TLC Site - - do they just require the (existing) immersion heater flex (heat resistant) to be looped through?
Does your daughter have one or two immersions ("sink" and "bath")
Is the immersion supplied from the general or the off-peak consumer unit?
Is the E7 meter controlled by timeclock or a teleswitch. The timeclocks can get out of synch and you would need to make sure your timer was using the off-peak period as defined by the meter timeclock
Owain
I took the opportunity of renewing the heater flex as the old one was a tad manky.
I replaced it less than a year ago when the switch burned out. Hopefully I left it long enough.
No, only the flex that goes into the immersion heater needs to be heat resistant. You can connect the wall switch to the timer with pvc flex if you wish.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "John" saying something like:
No, the timer goes in the supply cable before the immersion on/off (+ bath/sink) switch. The heat-resistant cable is untouched.
No, the timer goes after the isolation switch (usually a switched-fused-illuminated spur) and therefore, the heat-resistant cable needs to be rewired into the timer and a new flex fitted between the spur and the timer.
I Don't get the reference to the bath/sink switch. You must be thinking about something other than what the OP is referring to.
It isn't a dual element heater so the reference to sink/bath is not relevant. The comment of fitting it before the switch is interesting though. If fitted AFTER the switch I realise the switch will need to be left ON all the time to keep the timer running. Is there any other reason why it might be important to fit it before the switch (cable is buried).
In all likelihood, the timer will be rated at 3kW/13A, so it needs to be protected by a 13A fuse, which will be fitted in the spur. (The radial circuit for the immersion heater will be fused at 15,16 or 20A).
There should be no issue with leaving the switch on all the time.
The spur is already in place and connected to the fixed wiring. The timer should be fitted adjacent to the spur and the immersion heater flex looped through the timer. It's a no-brainer.
Immersion heaters usually use a 20A double pole switch not a fused spur.
If the timer is to be used as the sole control of the immersion heater (with boost controls etc for off peak times) then it does not matter which side of the switch it is fitted as the switch will need to be left on all the time to allow the timer to work.
Heat resistant cable is only needed for the final connection to the element.
Adam
And remembering to reset the timer if/after any power outages! Somebody posted here a few years ago stating that their heat storage time was off by several hours! Consequently, they felt, they were, in part anyway, using electricity to store heat during the 'higher' rate period? This very similar? But does it really save much electricity?
Hi,
This one will loop through on the existing flex. Cost me £5 in the remainder bin at Robert Dyas.
I remember - it is a proper Water Heater double pole jobby - with flex outlet- with engraved label.
Although she has E7 and night storage wasters the immersion is on the normal circuit. The reason for the change is she now has an electric shower and wants to cut down on the use of the immersion heater (a dual element would be ideal)
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Dave Osborne saying something like:
Oh, really? And how is the timer going to work, then, when somebody switches the immersion off in passing?
Commonly fitted here - dual element immersions. You'll notice I put that in brackets.
I used the heat resistant flex ruining over the top of the lagged tank from the dual element (bath and sink switch), located near the top of the tank, to the timer located on the wall in the airing cupboard. Ordinary cabling ran from the timer to the fuse box and economy 7 meter downstairs. Incidentally, the timer did not switch the immersion heater from sink to bath. That had to be done manually.
Bobby
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Bobby Bewl" saying something like:
The timer should go in the feed to the normal switch, that way you keep the times accurate and it matters not if somebody knocks the switch off.
Of course.
Some E7 immersion controllers will allow either bath or sink elements, but not both, so two elements can be run on one 13A circuit.
Owain
"Of course" indeed!
Bobby
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