Rubbish tube heaters!

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Clint

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Hello all,
Went to check on yesterday's brew to find the Inkbird at 16c!
Checked I hadn't left the probe out...again..nope. changed the heater fuse nope...found a pinched wire so cut back and fixed... nope. Bloody heater packed up...again! That's twice in three years and again just out of 12 month warranty.
I popped into town and picked up another,this time a Dimplex,1ft long..not including the end bit where the wire comes out! So..it doesn't fit directly where the other did as the bucket shelf needs moving and the door won't shut!
So...I've had to make a temporary shelf out of some off cuts I had and the added palaver of not being able to lift the fridge and get the cable through the drain hole I decided to cut a bit out the door seal for the heater cable.
Phew! It's all working now but leaves a few jobs when this brew is done..
 
Come to think about it the previous brew had the heater on more than usual so it was probably on its way out..the annoying thing is they seem to go just after a year...like there's a timer inside! Toolstation said they would have just replaced inside of a year..but the previous brand..whatever that was,they don't stock any more and have the Dimplex instead. It's not as if the heater is on constantly even when it's freezing a brew will keep itself warm in the fridge once it gets going.
 
hmmm, rather oddly I was advising somebody on facebook this very morning on how to test if it was his tube heater gone down (it was).
Then I have just been out to my Brew House and one of my tube heaters has failed, checked the fuse not that, disabled thermostat not that either. This was a Dimplex
 
I've had one die on me, just a generic jobby from eBay. Of the two I had then I'm fairly sure this was the newer one that died. The other one is still going strong now though this is obviously tempting fate.

There isn't much too them, it's just a coil of resistive wire in a metal tube. I had about people using 60W light bulbs instead (the old fashioned types with filaments).
 
I use one of these in my second brew fridge. It’s only 7w and struggles a bit but was still able to keep the FV at 18-19 degrees in the fridge in the shed when outside temperatures were below freezing.
That’s impressive, was it taped to the side of the FV?
 
That’s impressive, was it taped to the side of the FV?

I‘ve taped it to the shelf and the FV sits on it.

90FD0B6F-253C-4008-A14A-D38032B06E97.jpeg
 
That's twice in three years and again just out of 12 month warranty.
You should still be eligible for a refund as long as you've used it according to the manufacturer's instructions. If the manufacturer/retailer, speak to Trading Standards and make sure you mention it's not the first.
 
I use one of these in my second brew fridge. It’s only 7w and struggles a bit but was still able to keep the FV at 18-19 degrees in the fridge in the shed when outside temperatures were below freezing.
I use the 14w version and that keeps 28l at 20c easily. Cant understand why people use tube heaters.
 
When frequent failures like this are seen then it's normally because a product is being operated outside its design envelope. I suspect that the reason is stress due to extreme heat change (more than might be anticipated when used in an airing cupboard or greenhouse which have no active cooling system). The mechanism is this:
  1. Both the heater and fridge are in poor thermal contact with the item being temperature controlled i.e. 25 or so litres of wort which has a large thermal mass.
  2. At switch on say the wort is too warm, the fridge turns on. The bottom of the fridge where the rod heater is placed will drop to a very low temperature dependent on the fridge type in use. So the heater body will get very cold.
  3. After a period of cooling the wort hits target temperature and the fridge switches off. The body of the fridge remains very cold and some overshoot is likely. The controller should have some hysteresis set up but may not be sufficient to prevent the heater coming on.
  4. when the heater comes on it starts at a very low temperature, warms up to full working temperature before very slowly heating the wort.
  5. Again overshoot would cause the heater to be turned off and the fridge switched on thus rapidly cooling the heater.
  6. if hysteresis is set too low the cycle repeats.
Myself I use a brew belt wrapped around a stainless steel fermenter so the belt is in pretty tight thermal contact with the wort. Also I've built my own controller with an Arduino so I was able to design my own hysteresis algorithm to ensure that the system has a properly defined idle state.
I appreciate this probably doesn't help much but the above is the likely response from the technical department of the heater supplier - assuming you could ever get an answer at all!
if your controller has a set value for hysteresis it would be worth making sure that this is set to at least 1C and checking the system operation to ensure that it does not rapidly oscillate between heating and cooling.
 
....... I suspect that the reason is stress due to extreme heat change (more than might be anticipated when used in an airing cupboard or greenhouse which have no active cooling system).
........

I disagree, mainly because, when fermenting, there is almost no reason in the UK for a refrigeration facility for about 10 months of the year (+/- September to June).

During these ten months I very seldom switch the fridge on for fermenting and generally only use it for cold-crashing a brew prior to syphoning it off for use.

So far, my little Dimplex Tube Heater has lasted well over four years.
 
I had one in the garage that broke and i had lost the receipt so couldn't get a refund. They don't seem to be very reliable. With my heat mat and an stc as soon as it drops 0.3c it kicks back on and the fridge never needs to be used. Extends the life of the fridge, saves energy and does not stress the yeast.
 
I disagree, mainly because, when fermenting, there is almost no reason in the UK for a refrigeration facility for about 10 months of the year (+/- September to June).

During these ten months I very seldom switch the fridge on for fermenting and generally only use it for cold-crashing a brew prior to syphoning it off for use.

So far, my little Dimplex Tube Heater has lasted well over four years.
I think that you might be proving my point actually. If your fridge is not on then the effect that I describe will not occur, so this could be why your heater tube has lasted 4 years. Or you could just be lucky.
Heat cycling hot to cold using a temperature chamber or a hair dryer and a freezer spray is a very well used way of stressing circuitry & components in the electrical/electronics industry. It soon weeds out dry joints, intermittent faults or design weaknesses. But it was only a passing thought, it could simply be that tube heaters are a heap of unreliable **** under all conditions of use, unlikely though I would think.
 

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