how to test if immersion heater is knackered

[Taylortwocities]

[You didn't do (2), did you...

Nope, I bought a nice shiny new immersion spanner, and (because the little devil wouldn't shift) I added an extra length of pipe on to increase the handle length. = instant copper corkscrew

Still, I've got a nice Megaflo (well Ariston PWV) in my new house, + water softner + anti-corrosion sysem. Much better all round.

 

[Goldberg]

yes, but you'd need to know the resistance of a healthy element.. and I don't off hand..

should be fairly low though...

about 12-15 ohms if my maths is right??? ( 3000W/230V = 13Ohms )?

Again with this insistance on using 230V for calculations. It's always wrong if the rating for the load is stated at 240V.

you're only talking about £10-15 for a new element so if in doubt, change it..

I would say if in doubt leave it alone.

can't be that hard can it?

Have you ever had to remove an element when it needs sawing out?

quick spray or "cilit bang" and a smear of copper grease on the new threads before fitting would cure that I recon?

Is that something you learned on your WRAS course? Are you forgetting that the water is potable?

 

[sparkysm]

hi, going back to the original question, if there is live & neutral at the element terminals and it doesn`t get hot, its fooked (no need to test it)

 

[ban-all-sheds]

Are you forgetting that the water is potable?

Is it still classed as such when it comes out of a hot water cylinder?

Even it it's not been sitting around in an unsealed storage tank in the loft first....

 

[ColJack]

Again with this insistance on using 230V for calculations. It's always wrong if the rating for the load is stated at 240V.

we have to use it now for calcs..
besides, it errs on the side of caution with regards to current draw etc..

I would say if in doubt leave it alone.

..
he's confirmed power as far as the element so it's obviously either the element or the thermostat.. for such a cheap fix and a guaruntee on the new element it's worth a change...

Have you ever had to remove an element when it needs sawing out?

never had to change one full stop.. that's why I asked...

quick spray of "cilit bang" and a smear of copper grease on the new threads before fitting would cure that I recon?

Is that something you learned on your WRAS course? Are you forgetting that the water is potable?

what's WRAS? and I thought potable meant drinkable? I wouldnt't drink the hot water out of an immersion tank..
I meant on the external of the element threads for the limescale remover.. and the copper grease was meant in jest..

 

[Goldberg]

Are you forgetting that the water is potable?

Is it still classed as such when it comes out of a hot water cylinder?

No - that was an aberration on my part. I wasn't concentrating.

However, the chemicals that ColJack (apparently humously) proposed could pollute the water without anyone realising it, such that washing hands (and things) in that water could constitute a health risk.

 

[kirkgas]

Are you forgetting that the water is potable?

Is it still classed as such when it comes out of a hot water cylinder?

Even it it's not been sitting around in an unsealed storage tank in the loft first....

hot water in a cylinder is not potable (class 1 fluid), it is a class 2 fluid as it is class 1 which has been circulated through the tank and cylinder and showers etc, not sure a tiny amount would do any harm but probably not too clever to put it in a tank then wash your face in it

 

[ColJack]

what chemicals? cillit bang is used on sinks and taps all over the country..

there's probably more polutant in the water from the flux from soldering than you'd end up with from a couple of squirts of limescale remover on the outside of the nut..

 

[kirkgas]

what chemicals? cillit bang is used on sinks and taps all over the country..
there's probably more polutant in the water from the flux from soldering than you'd end up with from a couple of squirts of limescale remover on the outside of the nut..

coljack as i said not sure a tiny amount would be noticed in100+ litres of water, but i wouldn't spray it on my face for a quick wash, we are tough up here but there are limits

 

[Goldberg]

Again with this insistance on using 230V for calculations. It's always wrong if the rating for the load is stated at 240V.

we have to use it now for calcs..
besides, it errs on the side of caution with regards to current draw etc..

I contest the claim that you "have to use" 230V.

The fact is, if a heating element manufacturer states that it will consume 3000kW at 240V, then the current draw is 3000/240, not 3000/230.

If you want to "err", then why aren't you using 207V, since that's the legal minimum?

I would say if in doubt leave it alone.

..
he's confirmed power as far as the element so it's obviously either the element or the thermostat.. for such a cheap fix and a guaruntee on the new element it's worth a change...

Immersions elements should never be changed speculatively, because each change stresses the cylinder. I've never seen a faulty element that couldn't be diagnosed with the most basic of multimeters.

what chemicals?

The ones that you proposed be used - one of them you later said you had been jesting about.

cillit bang is used on sinks and taps all over the country.

And that's where it should be used.

BTW, you misquoted me earlier - I didn't write quick spray of "cilit bang", I wrote quick spray or "cilit bang", because I was quoting you.

there's probably more polutant in the water from the flux from soldering than you'd end up with from a couple of squirts of limescale remover on the outside of the nut..

That's an argument for not soldering, rather than an argument for using cillit bang.

 

[Goldberg]

2) Draw a line with a felt tip that runs from the IH to the tank body. As you apply torque to unscrew it, look very closely at the mark.

I'm curious - is this mark visible despite the spanner being in place?

5) You're stuffed.

Actually not, because:

0) Removing stuck immersion elements is one of the things that plumbers do for a living. But it's best to call them before (1), not after (5).

The last time I tried to cahnge an element it was so encrusted with limescale that I twisted the top of the tank trying to unsrew it.

You didn't do (2), did you...

Or (0)...

 

[Taylortwocities]

 

[BS3036]

As a matter of interest I just had to buy two immersion heaters. Same make. One measured 17 Ohms, the other 22 Ohms. So I don't think that the difference between 230V or 240V is worth talking about!

 

[ban-all-sheds]

I've never seen a faulty element that couldn't be diagnosed with the most basic of multimeters.

Or if it can be done, by temporarily bypassing the thermostat.

I'm curious - is this mark visible despite the spanner being in place?

Good point. Never had the luxury of a proper spanner, so it is visible with an open-ended tool. I guess you could draw the line over the spanner too...

5) You're stuffed.

Actually not, because:

0) Removing stuck immersion elements is one of the things that plumbers do for a living. But it's best to call them before (1), not after (5).

Where's your spirit of adventure....

 

[ban-all-sheds]

hot water in a cylinder is not potable (class 1 fluid), it is a class 2 fluid as it is class 1 which has been circulated through the tank and cylinder