help - bath pasteuriser problems with elements

[R G]

Perhaps the op could come back with some info and photos ??

 

[davesparks]

Well thanks for the info Dave, 240V it is for all calculation from now on.
Of course as you well know the supply voltage is allowed to be +10%, -6% from 230v (216.2 to 253v range) and does change through out the day as the load shifts.

And all substation transformers are set at 250/433V output, even the new ones.

 

[Leesparkykent]

Shouldn't you calculate the resistance from what voltage the manufacturer says? Ie 3kW at 230V or if it says 3KW at 240V.....last immersion I looked at said 3KW at 230V-240V

 

[davesparks]

Shouldn't you calculate the resistance from what voltage the manufacturer says? Ie 3kW at 230V or if it says 3KW at 240V.....last immersion I looked at said 3KW at 230V-240V

You should yes, but in reality the manufacturers haven't bothered to spend all that money changing their machinery to manufacture a slightly different element to give 3kW at 240. Much cheaper to change the printing on the sticker.

 

[davesparks]

I've checked my notes on a job I did a couple of years ago.
It was a system for storing, heating and pumping water for rain and stuff for an interpretive dance piece ('arts council funded' etc etc)
We had a 3000 litre tank in which we fitted a 6kW TP immersion heater at one end of the tank low down (approx 1/4 height)
Control was by a precision temperature measuring device with a remote sensor suspended in the tank.
A small submersible pump was also suspended in the tank to keep constant circulation of the water within the tank.

It took a few hours to get it up to the required temperature which was in the 40's

 

[telectrix]

this may help.

Water heating time calculator - Process Heating Services Ltd.Process Heating Services Ltd.

 

[JohnCider]

Hello all,
Clamp tested and coming up at 19.2 ohms.... but reflecting on this, Im sure that if the element is wired direct to power (via a 16amp plug) and are not heating sufficiently (and I agree that they should be heating that volume in around an hour) then surely its the elements that are faulty or unsuitable for purpose?
So - we are needing to look at other elements - need to be 3kw, flat (to fit a gap of 55mm high, and length 700mm including the terminals).
Can anyone recommend or add a link?

 

[Leesparkykent]

How has clamping it come up with 19.2Ohms?

 

[JohnCider]

STOP PRESS!
Well, after getting a tongue lashing from You know who, I have removed the elements from the tank, and lo and behold - on inspection they are engraved 240V/500watt.
Naturally, Im peed off with the company, (whom I have emailed), but at least I know what the problem is.......

 

[Leesparkykent]

So you definitely wasn't getting 19.2Ohms.....if you had tested the element with a multimeter.

 

[JohnCider]

No, definately getting 19 ohms - thats why I took the elements to look at them to see if I could see anything wrong.

 

[Leesparkykent]

No, definately getting 19 ohms - thats why I took the elements to look at them to see if I could see anything wrong.

At 500W it should be around 115Ohms.