Emmersion heater

[ruddyr1]

I havent used our emmersion heater for a few years as the rocker switch broke and I just use the central heating to heat water. If I replace the switch will it be safe to switch on? Or do they deteriorate having not been used?

 

[ricicle]

It's hard to say for sure. The only way to know before switching on would be to do an insulation resistance test on it and an element resistance test. It may be an idea to change it anyway to the modern type with cut-out in as well for peace of mind.

 

[EFLImpudence]

It may be an idea to change it anyway to the modern type with cut-out in as well for peace of mind.

That's only the thermostat.

No point replacing the immersion if not needed.

 

[AndyPRK]

A lot of peoples immersion is only there as a backup, not being used. So I wouldn't worry about yours.

 

[ericmark]

Be careful with thermostat where the only form of heating is electric than a non resettable thermal fuse is used. However this thermal fuse can rupture if any other form of heating raises the temperature above the fuses limit.

This has caused problem where solid fuel water heating is used as it can raise the temperature over the thermal fuse limit.

What is important is the material used to make the header tank. It can be made of a thermal plastic material which if heated can fail this did kill a baby when the water cascaded thorough the ceiling onto the baby below. As a result there was a move to non resettable thermal fuses.

With these poor quality header tanks the non resettable thermal fuse is a must but there are many heater tanks made of a sensible material able to stand boiling water which are (we hope) always fitted where solid fuel heating is used.

With gas it is down to the plumber involved he could fit either type. Personally I think the flimsy thermal plastic type should be banned and all should be thermal setting plastic which will not fail with boiling water but it seems this is not the case.

So the type of thermostat is dependent on the header tank used. Likely with gas using a non resettable thermal fuse would not be a problem but to have a device which can cause the back-up not to work when there is a fault with the gas boiler seems to me flawed.

So before replacing the thermostat do check what type of header tank is fitted.

This is yet another example where the electrician has to correct the plumbers errors in theroy with two forms of water heating thermoplastic heater tanks should not be used but fact is that they are.

 

[AndyPRK]

That's all very interesting, although header tanks arent that common these days.

 

[bernardgreen]

Thermostats do fail and over boiling may happen. The cut out will ( should ) turn off the immersion if the thermostat does fail in the ON position.

"These thermostats are not accurate. They are fairly accurate when they're first installed but when they've been in for a number of years the range of accuracy decreases.

Read more: http://www.dailymail.co.uk/news/art...irl-death-known-unreliable.html#ixzz36KmyagOp
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If it is noticed and the immersion heater is switched off the hazard of scalding water is prevented.

But if the over boiling occurs and the immersion is not turned off in time then the hazard is great.

One worst case disaster that a cut would have prevented was

http://www.dailymail.co.uk/news/art...scalded-baby-girl-death-known-unreliable.html

 

[RF Lighting]

That's all very interesting, although header tanks arent that common these days.

I would think half the houses in my area still have header tanks. My next door neighbour has a plastic header tank and a coal back boiler which regularly boils over

 

[ericmark]

That's all very interesting, although header tanks arent that common these days.

I would think half the houses in my area still have header tanks. My next door neighbour has a plastic header tank and a coal back boiler which regularly boils over

That is a problem with non resettable. Having the manual red reset button is still going to stop the boiling where a thermostat fails but will mean the thermostat does not need changing when the other form of heating causes the over heat only the red button needs pressing.

There seems to have been a knee jerk reaction to the babies death, but in the wrong direction it is the flimsy plastic header tanks which should be banned not thermostats with re-settable over temperature devices.

Please note not all plastic header tanks will fail with boiling water. It does not have to be steel there are hard plastic tanks able to stand boiling water. Only the flexible soft plastic ones are a problem.

As a kid we had a solid fuel stove and drawing off hot water when the water started to boil was a regular event. There was no problem the noise told one when it was boiling and there may have been from time to time water spilt onto the yard but one would have needed to be retarded to not realise what was happening. It was normal when the immersion heater was required to have to press the red reset button.

How anyone could sit in a house with the water boiling I don't know the noise was something else.

 

[bernardgreen]

Dumping 2 kWatts worth of steam into a loft for a few hours can make ceilings soggy enough to collapse.

 

[ericmark]

Dumping 2 kWatts worth of steam into a loft for a few hours can make ceilings soggy enough to collapse.

If one was at work yes but at home one could not help hear the noise. OK if very sound asleep maybe but one would have to be very sound asleep the noise is very loud.

 

[Adam_151]

Worth adding to this that in light of the tragic headlines quoted above, The NICEIC recommend that an immersion heater without a over temperature cut out when a plastic header tank is in use, is a recommendation code C2 on an EICR.

Now I know some will disagree with that, but if you are NIC registered then I think you need to be aware that, that is what they recommend, and be at least noting it down, even if you prefer to change the coding (perhaps you mark it as an observation without a code due to it not being a strictly electrical issue)

 

[JohnW2]

Worth adding to this that in light of the tragic headlines quoted above, The NICEIC recommend that an immersion heater without a over temperature cut out when a plastic header tank is in use, is a recommendation code C2 on an EICR.

It's always difficult to say things like this, since "one tragedy is always one tragedy too many". However, in that article the Coroner suggested that 10 million people were 'at risk' of this problem, due to a system which had commonly been present in homes for up to 60 years. If this were, perhaps, the first fatal incident of this type in 10 million people exposed to the risk for 60 years ....!

Now I know some will disagree with that, but if you are NIC registered then I think you need to be aware that, that is what they recommend, and be at least noting it down, even if you prefer to change the coding (perhaps you mark it as an observation without a code due to it not being a strictly electrical issue)

That makes total sense. Despite the above, if an electrician (or any other tradesperson) detects a potential hazard, (s)he should at least bring it to the attention of the householder in some way - as well as what we are talking about, that would apply equally to any potential hazards detected in relation to the gas installation, structural issues or whatever. However, as you imply, I'm not sure that it would actually be appropriate to 'code' it on an EICR (although the presence/absence of a cutout is, in some senses, an electrical issue, I don't think that BS7671 addresses it) - although, from what you say NICIEC members may have no real choice.

Kind Regards, John

 

[ban-all-sheds]

(although the presence/absence of a cutout is, in some senses, an electrical issue, I don't think that BS7671 addresses it)

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