Immersion heater test

[Redhotferrari]

Hi guys,

Can anyone give me detailed instructions as to how to use a multimeter to test Immersion heater and thermostat?

What settings do I use on meter etc?

Cheers

 

[corgiman]

What are you checking

the immersion heater or the stat?

 

[WDIK]

delete

 

[Redhotferrari]

Thanks corgi, Want to test both to ensure both are OK

 

[WDIK]

incidently while you have the lid off check that your stat is the newer type with a high limit, if its not then change it.


//www.diynot.com/forums/viewtopic.php?t=37170&start=30

see ChrisR FAQ post 36

 

[Softus]

with power fully isolated
set meter to resistance.
check resistance thru element, a figure of approx 13 ohm and infinity to earth would indicate a healthy element.

240/13 = 18.46 Amps.

What kind of elements are you used to?

 

[ChrisR]

Well the resistance is temperature dependent, so Softus' sum isn't accurate , but they're normally about 20 Ohms.

 

[WDIK]

sorry im giving the figure for current my faulty maths.

should read V2/watts (230v x 230v)/3000w



which = 17.63333 ohm, which is very close to 20 ohm

nominal voltage being 230v element being 3kw

 

[Softus]

nominal voltage being 230v element being 3kw

I believe that most elements are rated 3kW at 240V.

Well the resistance is temperature dependent, so Softus' sum isn't accurate

You're quite right of course.

but they're normally about 20 Ohms.

Except the ones that I measure, that are closer to 19 Ohms. But we're not trying to be accurate, are we?

 

[Agile]

check resistance thru element, a figure of approx 13 ohm and infinity to earth would indicate a healthy element.

That would give a power output of over 4 kW !!! And 18 amps through the 13 amp fuse!


I suggest that about 18 ohms element resistance would be more appropriate for a 3 kW element!

Tony

 

[WDIK]

check resistance thru element, a figure of approx 13 ohm and infinity to earth would indicate a healthy element.

That would give a power output of over 4 kW !!! And 18 amps through the 13 amp fuse!


I suggest that about 18 ohms element resistance would be more appropriate for a 3 kW element!

Tony

yes and and as you know well as you can read i apologised for giving that wrong figure using a wrong calculation,i confused current for resistance.
primarily because its a formular i would never use.
why?
because i would never do it that way.
but when some asks how to do it with a multimeter, i have to turn and say that no one should ever use a multi meter to perform these forms of testing.
as a live test.
a multimeter is not a recognised test instrument and should not be used when live testing.
so all i can do suggest dead testing techniques

 

[Softus]

That would give a power output of over 4 kW !!! And 18 amps through the 13 amp fuse!

Oh, well spotted.

Have another vat of wine, Agile.

 

[Agile]

The difference is that I know from previous regular measurements what results to expect when I test elements.

If I didn't then I could still use Ohm's law to calculate it.

I admit I replied without reading all the other replies others had given!

Tony

 

[WDIK]

That would give a power output of over 4 kW !!! And 18 amps through the 13 amp fuse!

Oh, well spotted.

Have another vat of wine, Agile.

yes althought he precise figure is 13.04A

look its a 3kw element and a 230v supply ok?

the maths work

 

[Softus]

look its a 3kw element and a 230v supply ok?

I very much doubt that. Have you measured your supply voltage recently?