Immersion heater.

Thinking ahead just in case it blows...............

The issue is length - I could measure the outside dimensions of the tank, but without taking the element out there's no guarantee there's no obstructions inside - and I could just measure the element if I took it out.

The easy way out is to buy one of the shorter folded elements, but I'm wondering if the effect on convection would be good or bad.

The tank is square, not cylindrical.

Thanks for any help.

Reply to
Ian Field
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The other issue is undoing without deforming the ever thinner copper of the tank. Heat up the thread section with a blow lamp before attempting to undo . Moderate torque plus tapping spanner with hammer , before upping the torque.

Reply to
N_Cook

The local DIY store offers a very flimsy looking pressed steel spanner that won't put enough torque on the element to do any damage.

There's a more robust looking box spanner on Ebay that would apply the torque with less risk of buckling.

The last element came out surprisingly easily - so I'm remaining optimistic.

Reply to
Ian Field

What size was it back then?.. :-)

I have a 27 inch element fitted at the top of a 42 inch cylinder. Water heating is normally by the CH coil but I occasionally test the immersion heater to make sure it works.

The manufacture's leaflet states:- "... this heater will only effectively heat water ABOVE, it is important that the correct length be fitted, i.e. if an 18" heater is used in a 36" cylinder only 45-50% of the water will be heated"

I have sensors at the top, 2/3 and 1/3 levels and a typical immersion heater test over a few hours shows that the tank is not fully heated.

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Reply to
Geo

Its square and not cylindrical, and the element is horizontal at the bottom - that may not accommodate as long an element as diagonal in a cylinder.

There is another threaded bush half way up the tank that I could add a second element if I wanted to.

Reply to
Ian Field

OK - with you now. Some simulations here:-

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useful only if yiou want to keep water hot for handwashing etc without heating the whole tank.

Reply to
Geo

You'll get a much better response in uk.d-i-y. sci.eletronics.repair is a rather weird place to ask a question about an immersion heater.

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Reply to
Mike Tomlinson

Yebbut you need so many filters - Harry, Roddy, Denis, Toughguy etc

Reply to
Geo

Aye, that's true. Can't say I blame you :)

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Reply to
Mike Tomlinson

A well insulated tank costs more to heat up from cold than keep topped up by the thermostat.

Not as bad heating half a tank from cold, but I'm guessing it would still cost slightly more.

Reply to
Ian Field

Except the rate of heat loss is dependent on the delta T between inside and outside. Colder tanks lose less heat, if they haven't already reached minimum, than warm tanks being kept warm, so it takes less energy.

Reply to
Tim R

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