Immersion heater question?

grahamc2003

Richie-from-the-Boro wrote: »

- element length - a pointless task relative to its outcome - I don't agree - if you could fit one twice the size you would heat the same area of water water in half the time before the stat switches the element off - the problem is its an immersion heater type tank .. .. not an E7 bottom element tank.

Whether you get more hot water with a longer element depends on the orientation of the element. If it's fitted horizontally, then maybe you're right, but mine is angled at about 45 deg, so would definately produce more hot water before the stat clicked off.

Just a general point, hope you don't mind - I often find your posts quite confusing as they frequently introduce irrelevant things, like, in this case, dustbins, which just serve to complicate the matter. Why you think an element at the top of a dustbin would cause the water to boil while one at the bottom wouldn't really escapes me!

alastairq

precisely, thank you...

the problem is..the old tank achieved better results..ie more hot water to fill the bath...than the new one does...and they are both identical as far as element position is concerned.

So..either the old element was a lot longer [therefore heating the water lower down the tank]....

and/or the thermostat was set at a higher temp [than the current 70 degrees]....thus heating more water, hotter...

The interface twixt hot water and cold would have been much bigger...hence tap runs longer before cold water emerges?


Because the old tank presented no problems in this respect....neither the plumber, nor myself, would query a like-for-like replacement. Nothing to suggest there should be a difference in performance.

I don't think cost was an issue.......certainly not to the LL.....

I agree the element is in the wrong place for my needs...However, there isn't much that can be done about that.

So..the purpose of longer elements is?

will they heat more water, further down the tank?

sorry, replying to richie-from-the-boro....but got leap-frogged!

I understand exactly what you mean......especially as..since hot water rises [and eventually forms a convection current]...so a bottom heater will be active for longer, maintaining a good outcome, which is a tank-full of hot water at an even temperature.

alastairq

How could he measure that, for just the immersion, if all his electric is on cheap rate for the 7 hours?

to be fair, I can do that...but just haven't had the desire to.

Since March, the E7 storage heaters have been switched off.

The only current draw overnight, apart from immersion heater, is the fridge/freezer.

If I switch that off tonight, at the same time take an off-peak reading, then come tomorrow, I'll have a reading solely for the immersion...providing I get dressed in the dark!

But I won't bother, since the recovery time from cold really isn't the issue.....the immersion is usually 'on' for 6 hours [to allow for power cuts/timer errors if I'm out]....plus at least an hour boost on a night....

Regarding lagging?

The temperature within the [airing] cupboard since the new tank was fitted has be noticeably cooler than before.

This leads me to believe, either the cylinder isn't being heated up to the same temp....or the lagging is much more efficient.

jalexa

Cardew wrote: »

How could he measure that, for just the immersion, if all his electric is on cheap rate for the 7 hours?

:rotfl:The OP has correctly worked out that apart from the fridge/freezer not much else need be consuming ovenight.

And the underlying reason for the suggestion which appears to have escaped you, is that the OP is concerned that the heat content of the cylinder, for reasons unknown, is inadequate (at least compared with previously). An overnight check of consumption may (or may not) be informative.

Any better suggestions?

DirectDebacle

Not necessarily better.


Turn the adjusting screw to min then back to max and see how that goes. May be stuck or just faulty. If no better after trying this get plumber back to change the stat or whole unit.

Edit

alastairq

DirectDebacle wrote: »

Not necessarily better.

OP have you removed the cover of the immersion and checked what the thermostat is set to. Should be @ 60-65.
Turn the adjusting screw to min then back to max and see how that goes. May be stuck or just faulty. If no better after trying this get plumber back to change the stat or whole unit.

thanks..........yes, done that...also fitted a new stat...done likewise.

does anybody know if new cylinders [and immersions] need 'running-in' to get up to optimum performance? I.e., will it 'improve' with time?

DirectDebacle

Not to my knowledge. Think of HW Cyl & immersion as similar to giant electric kettle.

Cardew

jalexa wrote: »

:rotfl:The OP has correctly worked out that apart from the fridge/freezer not much else need be consuming ovenight.

And the underlying reason for the suggestion which appears to have escaped you, is that the OP is concerned that the heat content of the cylinder, for reasons unknown, is inadequate (at least compared with previously). An overnight check of consumption may (or may not) be informative.

Any better suggestions?

The OP said he had storage heaters and:

Therefore the hot water boost from cold is done during off-peak hours...as is the washing machine, tumble drier, and anything else I have which guzzles leccy.......[they all have timers...useful little things, really]

If you only have one element I do not understand the role of the timer. How long "*exactly* is "proper heating time" and at what time?

Normally an "Economy 7" cylinder would have 2 elements, a lower main element connected (only) to overnight "cheap-rate" and a upper "top-up" element connected to the timer

You are sure, now it has been explained to you, that you understand that all his electricity changes to off-peak for 7 hours; which is why he needs a timer.

Or were you just talking about an 'element connected(only) to an overnight cheap rate in order to 'tease out' an explanation from the OP?

Cardew

[QUOTE=alastairq;47727781
Even when running a bath, the water temp is sub-60 degrees [measured last night]...so either the thermostat is new-but-faulty...or the tank input cools the hot water too quickly? .[/QUOTE]

If the thermosts is set to 70C and the the bath water is sub 60C then it seems pretty certain that the thermostat is faulty IMO.

To settle all discussion on length of immersion and various theories etc, anyone with good electrical knowledge(an electrician) could just bypass the thermostat as a one off experiment and check the water gets much hotter.

Obviously remove bypass after one off experiment.

This shows how to remove a thermostat's wiring.

http://www.diydata.com/problem/immersion/immersion_heaters.php

jalexa

Cardew wrote: »

The OP said he had storage heaters and:







You are sure, now it has been explained to you, that you understand that all his electricity changes to off-peak for 7 hours; which is why he needs a timer.

Or were you just talking about an 'element connected(only) to an overnight cheap rate in order to 'tease out' an explanation from the OP?

Good grief. What petty point are you trying to make instead of trying to help the OP?

From the OP's first post the (apparent) issue has been lack of delivered heat from a new cylinder/stat combo, but as several posters noted and the OP eventually conceded, the OP lacked detail.

As I "quoted" earlier...

OK, perhaps I should have said "I do understand the role of the timer..."

What I was really trying to do was to tease out whether the OP understood the role of the timer and "proper heating time"...

I think a clear answer to your latest "petty point post" question.

You chose to ignore the relevance of "proper heating time" and its (unstated) relationship to energy acceptance of the cylinder. I let that omission go realising you would eventually put your other foot in it.

Which you duly did.