Temp Cont. Fridge With Submersible Ceramic Heater For Temp?

[buckerooni]

Hi All,

I've got Temp Control Fridge Mk I going, but am wondering if using (submersible) ceramic heater element that came with the kit (2nd hand) is a good idea. I'm wondering if it's too hot to maintain a good average temp. I haven't used the fridge to ferment yet.

Pointing the ($25) infrared thermometer at it the element is reading at 90c+ while on the other side of the fridge the temp sensor is coming in at 18.1c. I'm worried it's a bit too dramatic heat difference between what the element is outputting to the desired temperature to ferment. That is, one side of the fermentor will hotter than the other

So I'm after advice on:
- worth using a light globe instead (or can I get by with the element?)
- positioning of sensor, heat source and fermentor in the fridge
- will the gap in the seal make much difference?

here's the gear (working it's way up to 18c) - using a 1 degree temp range (falls below 17 will heat to 18):

here's the gap:

Thanks for any help!

Cam.

 

[glenwal]

You say its submersible. Do you have a vegetable crisper at the bottom of the fridge? My heating is done with a fishtank heater in the crisper full of water. Takes up basically no space (since i'd have a shelf over the top anyway - as you appear to - because of the compressor hump), and adds a fair wack of thermal mass to the heating element to eliminate the hot spots.

Just be sure to close any "vents" on the crisper (or wrap it in glad wrap) or you'll end up with plenty of condensation inside the fridge which will end in mould.


edit: And the gap in your seal looks fine - pretty much the same as most people i think.

 

[buckerooni]

thanks Glen - that's awesome! will chuck the crisper back in, fill with water and put the submersible element in there and wrap it in gladwrap - what a great idea!

 

[Wolfy]

A very interesting idea there from Glen W.
What you could also do (assuming your temperature probe is just in the airspace of the fridge) is to immerse the probe in a container of water, or even stick it to or on the fermentor, so you get a more stable reading of the internal temperature. I'd also have suggested using a 12V computer fan to circulate the air, that way you'd essentially eliminate any hot-spots without the need to fill the fridge with even more water.

 

[buckerooni]

this has worked well so far with a much more even temp around the fridge - very happy!

 

[seravitae]

Just putting it out there, submersible/immersion heaters *usually* are not designed to run dry, ie out of water.

I would be very careful to ensure that the element is allowed to run dry, but submersible heating element and 'dry' dont generally mix well.

The idea of using the crisper full of water with the element submersed is a great idea.

 

[buckerooni]

here's the new improved temp controller with the element in a crisper full of water covered in gladwrap. Didn't trust the fermenter on the fridge shelf so I grabbed 'a chair' inside :huh: