Turbo oven dead...

borat123

My faithful mod'd halogen TO has finally given up the ghost after serving faithfully for the past three years or so.  It sets off the circuit breaker every time it's plugged in, even without the element switched on.

Lucky I still have the old solid event TO as a spare so I used that today to roast up a couple of kilo's of Ethiopian.  I forgot how bad the lag is compared to the halogen, and also the temp ramp capability is slightly less.

Anyway, I'll pull it apart and take a look inside. If nothing obvious it's going to the local appliance repair man to see what he can do.

UNM

if you cant find anything obvious, give it a spray with electrical contact cleaner, or brake parts cleaner. Cleans any carbon deposits off that can cause slight earth leakage. I am assuming that it is an earth leakage (aka RCD/GFCI) breaker. If a simple current based breaker, you have a serious short and that should be easy to catch. Over here, it is far cheaper to replace than repair, but perhaps pricing is different there. Good luck

Brett H

I can't believe that there wouldn't be a plethora or turbo ovens to choose from in the desert??? Seriously though here's hoping you're up and running soon.  I had chaff all through the internals kill one of mine and I'm convinced that their performance degrades in a relatively short period.  Good luck mate!

derrilex

Just pick up a couple of dozen of them next time you fly to China :thumb:

Koffee_Kosmo

I was also going to suggest an electrical cleaner and if that did not work replace it with a new unit KK

borat123

Thanks for the tips. Yes I was thinking earth leakage as well. Took it apart and the inside was filthy - covered in a light tan coloured dust. It almost looked a bit like mould but was dry and powdery rather than damp. Inside there was nothing obvious, and it's now nice and clean and been sprayed with contact cleaner. Putting it back together now and we'll see if it's working gain.  If not, labour is so cheap over here, it's cheaper to repair than buy a new one!

galumay

Hey Borat, they always seem to look like that inside, its like some sort of alien foam or something! I am giving up on the TO's and going to the high end Steinel Heat Gun solution, will post a thread up when the bits come and report on success or otherwise! There is another user who inspired me to try this path, http://www.bestcafes.com.au/forum/roasters-different-roasting-equipment/kkto-roaster-with-heat-gun-as-alternative-heat-source/  (the second solution)

borat123

Problem solved! A good clean seems to have fixed it.  Not bad I guess, considering that was it's first internal clean in three years... I'll have to try being a bit more diligent in vac'ing through the side grills after each roast in the future.

Koffee_Kosmo

on 1379234421:

Problem solved! A good clean seems to have fixed it.  Not bad I guess, considering that was it's first clean in three years...

Very good mate  :thumb: Your back in business KK

GaryatGala

Reviving this thread, my Cookwell halogen oven has died, so I bought another one of the same (still only $39.95 at Homeart). Bought it back, took off the heat shield and gave it a blast. Astounding to find out that this second oven runs 40+ degrees hotter than the last one according to the DMM logger and thermocouple. So I gave the usual 625 gm of beans a go using the same heat settings as on the original oven and promptly did a 11.50 minute roast. WTF? Turned down the dial down to 150 deg for pre-heat and 190-200 deg roasting. Time was longer but still rather short at almost 14 minutes. By now the silicon rings have scored significant bubbling due to the heat. So now I,m at the re-tweaking stage again. Has anyone tried a second identical oven and discovered any variances to the first one?

GaryatGala

Tried the oven with the shield on but the results were not as satisfactory as the shield off result. Beans have a burnt mottled look as well as not as much expansion in bean volume. They don't have the healthy brown color, more like a dark grey baked look. Heat settings were at maximum. Roast time was 23 minutes.

Koffee_Kosmo

Try an in between heat shield tweak In my tweak I cut 4 X 32mm holes with the hole saw in the plate One in the centre and three in a triangle shape on the circumference Attachment not found.Attachment not found.Attachment not found.

GaryatGala

A hole saw. Hmm..what is that? New year,s resolution perhaps, build up an man cave tool arsenal if my wallet approves. I still got clay from the coretto lid days..can I do sonething with that????:D Will try drilling out bigger holes with the biggest drill bits i got lying around. Thanks KK for your tip. I,m still scratching my head thinking maybe the first oven i had ran too cool and this second one i got now runs too hot. At least i,m not going to be concerned about an roast that,s going too slow and i have the ability to turn the heat up or down with the range i have available now. ;D

GaryatGala

Update. Am quite happy with the heat shield off and using lower heat settings to achieve a normal looking roast profile. The burping of the oven and/or turning down dial (in this current case, down to 150 deg displayed to for approx. 3-4 minute gap between 1C and just before 2C!). The taste in the cup is still superb as before. A 1 kilo roast is easily achievable now that I got this roaster on steroids. Got the roasting station rebuilt. A few videos to be done. To be continued...

Koffee_Kosmo

on 1388626099:

Update. Am quite happy with the heat shield off and using lower heat settings to achieve a normal looking roast profile. The burping of the oven and/or turning down dial (in this current case, down to 150 deg displayed to for approx. 3-4 minute gap between 1C and just before 2C!). The taste in the cup is still superb as before. A 1 kilo roast is easily achievable now that I got this roaster on steroids. Got the roasting station rebuilt. A few videos to be done. To be continued...

Very good Gary I also do 1 kg roasts with the halogen roaster KK

QM0996

I have had about 4 TO to date as some have been used for experiments  >:D The current one is very HOT. It is not the element so much as the thermistor as it is a basic type and thus subject to a wide tolerance. Add in the slight changes to the element ( 1100W / 1200W / 1300W / 1400W )  and the tolerances and the element type and 50C change as per setting on the dial would be normal....

borat123

Hi Gary, did you try a 1kg roast yet?  If so, how many degrees per minute ramp is it giving you?  I only seem to get a max of around 10 at that weight.  If your new TO is significantly more than that, I may have to go out and get a new one....

Koffee_Kosmo

on 1393235687:

Hi Gary, did you try a 1kg roast yet?  If so, how many degrees per minute ramp is it giving you?  I only seem to get a max of around 10 at that weight.  If your new TO is significantly more than that, I may have to go out and get a new one....

I use that highlander TO you recommended to me Modified the fan guard and for 1 kg roasts - without a stabilising period I normally get 1 st crack at approx 14 min and for hard beans at approx 16 min KK

borat123

Thanks KK, yep that's pretty much exactly what I get...  I had hopes the Chinese had released some new secret TO with a higher rated element.

Koffee_Kosmo

on 1393251636:

Thanks KK, yep that's pretty much exactly what I get...  I had hopes the Chinese had released some new secret TO with a higher rated element.

They will if I ask them, but one needs to purchase a 5000 unit min order

QM0996

on 1393284095:

They will if I ask them, but one needs to purchase a 5000 unit min order

Yes and then there is the issue of restrictions as to the max temp the units are allowed to reach; on these types of devices.  250C  In general the bi metal strip type are limited to 250 Max.  Mass produced and cheep. You can get replacement thermostats that will go to 275 and or even 320 but they can cost as much as the TO alone. Then all you need is a good Quarts element.  I by passed the thermostat on 3 units and two failed not long after due to the actual terminals at the element ends melting / disintegrating due to extend high temps. Then I got lucky with the thermostat and element in my latest TO AND it is a trooper. KK. Need to get all your stuff and drawings and etc and I will soon be able to build for you.

Koffee_Kosmo

It's ready when you are QM  :thumb:

QM0996

on 1393301935:

It's ready when you are QM  :thumb:

Thursday or Friday...  at the earliest... But due to ongoing heating issues I also need to revise / re manufacture the mixing arm... Lets say we make a Date and Time for next week..

Brett H

on 1393315511:

Thursday or Friday...  at the earliest... But due to ongoing heating issues I also need to revise / re manufacture the mixing arm... Lets say we make a Date and Time for next week..

This smells like trouble...  :thumb:

Koffee_Kosmo

on 1393315511:

Thursday or Friday...  at the earliest... But due to ongoing heating issues I also need to revise / re manufacture the mixing arm... Lets say we make a Date and Time for next week..

Contact me when you're ready via the many methods we have done so before KK