Immersion heater time taken to heat a tank of water

[Horatio1960]

Current setting is at 60 degrees as 55 was not heating water enough whereas it used to

However if the standard is now a top entry 27" element and there are still plenty of houses with just an immersion heater for water, I simply cannot believe that the experience I have had with this one is normal or acceptable

I would have expected to find thousands of complaints on the subject which I didn't, only isolated cases in the main with a cause in a lot of them

So I understand the bottom element would be more efficient but cannot believe the top fitted element we have is working correctly

I still have the thermostat to check for length, next would be the operation of it

 

[EFLImpudence]

Another useful addition from me.

Perhaps the thermostat is duff.


You say that you have adjusted it; they usually come these days with a seal to stop you doing that.
Was there a seal on it?

Not complaining if you have, just interested.

 

[JohnW2]

Is it not just a case that the stat is turning off the element, due to the 55deg temp at the top of the tank, before heating the bottom section fully. whereas the old bottom element may have run longer as the bottom never really got to 55 deg much but the majority of the top part of the tank also got heated, hence more hot water.

That makes theoretical sense but, in practice, it seems that most people get more-or-less a full tank of hot water with a top-mounted 'long' element (and 'long' thermostat') - thinking back (many many years) to when I had a top entry immersion, I think that was the case for me. If that's the case, I guess the thermostat has to be up to its 'set temperature' along most of it's length before it switches the element off (or maybe the 'temperature sensing' bit is at the end?) - since, otherwise, it would switch the element off when there was only a small amount of hot water at the top of the cylinder!

Kind Regards, John

 

[JohnW2]

Another useful addition from me. ... Perhaps the thermostat is duff. !

If that hasn't already been suggested (I thought it had, but maybe I dreamed that), it is, indeed, probably the most likely/'obviopus' explanation. I've certainly experienced that myself.

Kind Regards, John

 

[Horatio1960]

The immersion was purchased in May last year and is to the latest spec, it has the same type of adjustable temp setting as I have usually seen

I seem to remember reading of the later ones being sealed from over adjustment

 

[EFLImpudence]

Another useful addition from me. ... Perhaps the thermostat is duff. !

If that hasn't already been suggested (I thought it had, but maybe I dreamed that)

I suggested earlier that the immersion may be faulty. I wasn't including the thermostat then - hence my 'useful' comment.

 

[333rocky333]

But didnt he say the top water was scalding hot suggesting the stats not operating early, set any higher and it might trip the safety stat
Im sure I snapped a stat once and the sensing thing run to the end, though im sure with a 27" stat the stat housing is nowhere near that length, let alone the stat length.
As for the element, a simple resistance test will confirm its ok and what wattage.
Just a quess but can you get airlocks in tanks, I assume it has just an open vent pipe

 

[Horatio1960]

Correct re scalding if set any higher

Whilst it heats some water at the top of the tank, its only very hot for a short while and loses its heat fairly quickly as there is more cold water in the tank than hot

Its just open vented so can't see the possibility of an air lock being involved

I am leaving it on overnight and will check what happens in the morning, I suspect not much better if anything

Another obvious sign to the difference between old and new is the airing cupboard doesn't get warm in the slightest, previously there was plenty of water so the airing cupboard was warm

As I and others have suggested I suspect the thermostat is a duff one

 

[EFLImpudence]

But didnt he say the top water was scalding hot suggesting the stats not operating early,

Good point but perhaps it should wait until it's hotter farther down.

 

[JohnW2]

deleted - duplication of EFLI!

 

[333rocky333]

Maybe find time to dismantle the cuboard
check the length of stat and stick a metal coathanger down the housing, if deep you maybe able to fit a longer stat

 

[SimonH2]

Is it not just a case that the stat is turning off the element, due to the 55deg temp at the top of the tank, before heating the bottom section fully.

That would be my guess.
I've not really studied them in great detail, but I did study one that I thought was faulty (just needed adjustment in the end - the stated temps on the scale were wrong). It's construction was very simple : The threaded rod that the adjustment knob work on simply goes through to the far end and is crimped into the end of the outer tube. So it's sensing the temperature all along, and effectively will sense the average temperature along it's whole length.

 

[ban-all-sheds]

Is it possible that the immersion heater you fitted was a dual type? There used to be some with two elements, one only heats the top section of the immersion heater and thus only the top part of the water, the other heats the whole length. I think the logic was that you had two switches, one for small amounts of water, the other for the whole lot. It was supposed to save money by not heating excessive amounts of water. I fitted one like that about 4 years ago in Southern Ireland but have not seen one in the UK for a long time.

That's the type I grew up with.

 

[kai]

You can't seem to buy the dual ones any more - I can't understand why.
Modern economy seven setups have two immersions in the side of the tank, one top and one bottom.

 

[ban-all-sheds]

With a dual you have to discard and replace a working element when the other one fails.