Immersion Heater Woes

[locost]

Bought myself a Stokes SG3, a 2400W over the side immersion heater element.

Tried it out last night on 40L of water, only to discover that after 4hrs, the heater could not bring the water to the boil:-(

I guess the dimensions of my kettle are the cause of this (Hieght 400mm, Diameter 400mm), but I really need to resolve this problem as cheaply as possible (SWMBO etc.).

What are people's experience with this kind of element and what would be the cheapest way to a solution?

 

[Justin]

Hmmm. Almost sounds to me like your heater might be bung-I'd look at taking it back and talking to the blokes who sold it to you. 2400W should get that 40L to a good rolling boiling and well withing 4hrs.

Although I've never used one for boiling (Well I have but I used the immersion and gas together to speed things up), I mainly used one for stepping up/maintaining/correcting mash temps. I have however used other electric elements in my HLT for boiling water (just normal jug ones). I have an 1800W and 2kW element in my HLT, both will bring 40L of water to the boil and maintain it on their own (just the time varies really). My HLT is a keg so much bigger than your kettle diameters.

So something isn't right IMO, you should be getting much better performance out of that. Lots of people are using those for their kettles.
I'm keen to see what others have to say here but I'm sure they will agree with me that something is suspect with your element.

Cheers and good luck.
Justin

 

[jgriffin]

I use a 2400W element, i've had it do 30L in about 20mins.
So i'd say that there might be something wrong with it.

 

[user 384]

Based upon my calculations, a 2.4kw element (and assuming 10% inefficiences), should raise 40litres of 20C water to 100C in 102mins.

However this is just the theoretical calculations based upon the energy output of an element and the energy required to heat water. In the real world I reckon you're pushing the limits of a 2.4kw element with 40ltrs.

Cheers
MAH

 

[big d]

i tend to agree with mah on its limits.ive a 2400 w heater and trying to heat already warm territory water was taking ages(hours).i found i needed to use my 2 ring burner in conjuction with the element.
these days since upgrading everything i only use the element to heat the sparge/mash water which the element does quite well.mind you i give it a help by starting with hot tap water on the hlt.this still takes a bit of time but it gives me the time to get the rest of the stuff sorted.

cheers
big d

 

[user 384]

As a side note I use a 2.4kw element in my boiler. I only make batches big enough for a single 18 litre keg. This means I need to start my boil at 28 litres (allowing for losses to the kettle, boil off, losses to the fermenter etc). My element takes about 30mins to get to boil (this is the runnings which are already at about 65C), and then keeps a nice gentle rolling boil. I personally wouldn't go any larger than 28ltrs with this element.

Cheers
MAH

 

[locost]

That might explain what happened last night, the water seemed to heat up quite qickly but after an hour or so it just seemed to sit there at a point just below "simmering". I recall from my high school physics that to achieve boiling (ie. evaporation occuring within the main body of the water) an extra bit of energy is needed. Perhaps 2400W with 40 L is just too small to kick the water over into boiling.