Checking an immersion heater.

peweuk · 17 May 2015

Taylortwocities said:
A new element+thermostat should ensure that a cutout is provided. Sometimes they are in the element housing, sometimes they are part of the thermostat.

Its false economy not to replace both.

This was exactly what I said to the company when I spoke to them. Particularly as it was obvious that the installation was at least 20 years old and the immersion had obviously never been replaced since the tank was installed.

He chose to ignore my comment at the time.

Taylortwocities · 17 May 2015

You can get thermostats with an integrated cut out, useful to make an older (non-compliant) immersion heater meet todays safety standards.

See pic below with cut-out reset button.

Untitled

Taylortwocities
17 May 2015
1
immersion

JohnW2 · 17 May 2015

Taylortwocities said:
You can get thermostats with an integrated cut out, useful to make an older (non-compliant) immersion heater meet todays safety standards. See pic below with cut-out reset button.

Thanks. As I said, I've never seen one of those. I do, however, still feel that it is theoretically marginally 'less safe' than having a cut-out which is totally independent of (and physically separate from) the thermostat.

Kind Regards, John

EFLImpudence · 17 May 2015

JohnW2 said:
I do, however, still feel that it is theoretically marginally 'less safe' than having a cut-out which is totally independent of (and physically separate from) the thermostat.

Could you not say the same about being independent of the element?

As long as it works ...

peweuk · 17 May 2015

JohnW2 said:
Thanks. As I said, I've never seen one of those. I do, however, still feel that it is theoretically marginally 'less safe' than having a cut-out which is totally independent of (and physically separate from) the thermostat.

Kind Regards, John

The one they fitted to mums immersion has one of those reset buttons. But when power was turned back on the fault on the element welded the contacts on the stat closed.

I am all for safety - particularly in a block of flats for the elderly.
Can you point me to a link for an external cutout of the type you are referring to.

JohnW2 · 17 May 2015

EFLImpudence said:
JohnW2 said:

I do, however, still feel that it is theoretically marginally 'less safe' than having a cut-out which is totally independent of (and physically separate from) the thermostat.

Click to expand...

Could you not say the same about being independent of the element?

The usual ones surely are essentially 'independent of the element', aren't they - they are simply mounted on part of the structure which supports the element?

EFLImpudence said:
As long as it works ...

Sure, but is it not more guaranteed to work (in the event of primary thermostat failure) if it is independent of the thermostat? If, for example, the primary failure was the result of (or resulted in) some burning/melting of parts of the thermostat - can you not imagine that possibly resulting in failure of a cut-out which was integral with the thermostat?

Kind Regards, John

Taylortwocities · 17 May 2015

peweuk said:
Can you point me to a link for an external cutout of the type you are referring to.

The"external" cutouts are a built-in part of the immersion element housing itself. Its not something that can be retro-fitted.

That's why you can get stats with them built in.

JohnW2 · 17 May 2015

peweuk said:
The one they fitted to mums immersion has one of those reset buttons. But when power was turned back on the fault on the element welded the contacts on the stat closed.

Including welding closed of the contacts of the integral thermal cut-out, I wonder?

peweuk said:
I am all for safety - particularly in a block of flats for the elderly. Can you point me to a link for an external cutout of the type you are referring to.

I'm not at all sure that one can get them as standalone devices (I doubt it, but someone may correct me!) - most elements now sold include such a thermal cut-out built into their housing.

Kind Regards, John

EFLImpudence · 17 May 2015

JohnW2 said:
EFLImpudence said:

As long as it works ...

Click to expand...

Sure, but is it not more guaranteed to work (in the event of primary thermostat failure) if it is independent of the thermostat? If, for example, the primary failure was the result of (or resulted in) some burning/melting of parts of the thermostat - can you not imagine that possibly resulting in failure of a cut-out which was integral with the thermostat?

No more than anything else.
I don't know exactly how they are made (innards) but I suppose some burning (what burning?) would operate it.
They are to stop the water overheating - not electrical faults.
There's always one unlikely scenario which will cause a safety device not to work.

Should we fit an element with one, a thermostat with one and for good measure a tank stat. as well?

JohnW2 · 17 May 2015

EFLImpudence said:
They are to stop the water overheating - not electrical faults.

Indeed, but they stop the water overheating by opening electrical contacts - and that situation will only arise if/when other parts of the thermostat innards have already failed (and maybe burned/melted - themselves and things around them).

Kind Regards, John

333rocky333 · 17 May 2015

In my veiw the overheat part is fitted more for the fact that when it operates it LOCKS off until manually reset.
Thus safequarding the system overheating cooling down and overheating by the initial stat cycling on /off possibly by the client hazourdly turning the temp on the normal stat too high

For the Op, i think what TTC meant was its good practise to fit a new stat when fitting a new element.

The other way round, due to the possible complications draining down etc.
If the element tests ok then it would be normal to fit the stat only.

Proberly why stats are sold on there own, but ive never seen an Element sold without a stat fitted

JohnW2 · 17 May 2015

333rocky333 said:
In my veiw the overheat part is fitted more for the fact that when it operates it LOCKS off until manually reset. Thus safequarding the system overheating cooling down and overheating by the initial stat cycling on /off possibly by the client hazourdly turning the temp on the normal stat too high

That's interesting - I'd always thought/assumed that the overheat thingy did not operate unless the water temperature rose to above the highest temperature which could be ('legitimately') set for the thermostat.

But surely there is something wrong here? Why do they make and sell (or why are they allowed to make and sell) thermostats which can be set to temperatures which a (now 'required') safety device regards as dangerously high - and therefore over-rides (in a semi-permanent fashion) the thermostat?

Kind Regards, John

peweuk · 17 May 2015

333rocky333 said:
If the element tests ok then it would be normal to fit the stat only.

The problem in my mums case is that they fitted a new stat when the element was obviously not OK (see the pic in earlier response) and in doing so have destroyed a new stat and a very expensive timer (although they will point out that I cannot prove the latter).

333rocky333 · 17 May 2015

JohnW2 said:
333rocky333 said:

In my veiw the overheat part is fitted more for the fact that when it operates it LOCKS off until manually reset. Thus safequarding the system overheating cooling down and overheating by the initial stat cycling on /off possibly by the client hazourdly turning the temp on the normal stat too high

Click to expand...

That's interesting - I'd always thought/assumed that the overheat thingy did not operate unless the water temperature rose to above the highest temperature which could be ('legitimately') set for the thermostat.

But surely there is something wrong here? Why do they make and sell (or why are they allowed to make and sell) thermostats which can be set to temperatures which a (now 'required') safety device regards as dangerously high - and therefore over-rides (in a semi-permanent
fashion) the thermostat?

Kind Regards, John

In the past I have known the high temp to operate even though the normal one appeared ok, the max setting on the normal bit is a lot lower than the high level stat I recall, but I was once told if the initial stat is set quite high and the water in the tank is not drawn off, although the initial stat has shut off the element, the standing water temp still increases sometimes to an unacceptable level, triggering the over stat.
in a commercial envirement with the water in constant use more I suppose you can get away with a higher setting on the normal stat.
I may have been fobbed off with excuses, I dont know

333rocky333 · 17 May 2015

peweuk said:
333rocky333 said:

If the element tests ok then it would be normal to fit the stat only.

Click to expand...

The problem in my mums case is that they fitted a new stat when the element was obviously not OK (see the pic in earlier response) and in doing so have destroyed a new stat and a very expensive timer (although they will point out that I cannot prove the latter).

Apreciated, in your case it appears through incompetence,
though what im saying is the element will most likely automatically come with yet another stat.
In my veiw the company should at worst write off the whole cost and at best replace the timer regardless of whether the initial fault took it out

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Checking an immersion heater.

Similar threads