Ebay Aquarium Temp Question

I have everything wired up, and it is working good, but it seems like the cycle times for the fridge are a bit too frequent. I am using a full size fridge, and have added a few gallon jugs of liquid to act as a heat sink, but am thinking that I may need to put the temp probe in a jug of water as well. Anyone tried this? Here are some pics so you can get an idea of the setup. The controller is wired for heat, but I haven't added the space heater yet due to it consistently being well above 60 in my garage this time of year. I have my temp swing set @ 1 degree C. I haven't added a reinforced top shelf yet, but once that is done I will be able to handle 4 fermenters at once.

putting the probe in water will reduce temp swings. 1* is a pretty small window to set for your temp. it's your choice if you want to keep such tight temp control but it will greatly reduce the life of your compressor.

autobaun70 said:

I have everything wired up, and it is working good, but it seems like the cycle times for the fridge are a bit too frequent. I am using a full size fridge, and have added a few gallon jugs of liquid to act as a heat sink, but am thinking that I may need to put the temp probe in a jug of water as well. Anyone tried this? Here are some pics so you can get an idea of the setup. Anyone tried this? Here are some pics so you can get an idea of the setup.

Click to expand...

You need to turn the controller/fridge off immediately. You may fry your compressor in just days/hours, depending on the short cycle prevention it has built in. The controller comes defaulted to 3 min, which is barely enough. Your probe appears to be in the direct air stream of the evaporator fan. This will cause the probe temp to drop below the SP almost immediately upon cooling, then rise almost immediately afterwards because no appreciable cooling took place.

RE: probe and larger thermal mass- Yes, this has been done, and you can find more info in the ebay aquar. controller thread. Most suggest taping the probe to the active fermenter, then insulating it (probe only). When you don't have an active fermenter in there, you can tape the probe to the side of a jug, then insulate it (probe only). Waterproofiness of the probe doesn't have to be worried about that way.

I would suggest a minimum of a couple of cornies/sixtels in there.

autobaun70 said:

The controller is wired for heat, but I haven't added the space heater yet due to it consistently being well above 60 in my garage this time of year. I have my temp swing set @ 1 degree C. I haven't added a reinforced top shelf yet, but once that is done I will be able to handle 4 fermenters at once.

Click to expand...

You can leave the temp diff at 1C or even lower it to .5C as long as you have the probe on a 2 liter jug or bigger. If you are a "probe in air" type, a temp diff of 3-5C is more acceptable. Set the compressor delay to its max- 10 minutes.

You may be able to fit 4 fermenters in there, but only one active fermentation at a time can be accurately controlled. Once a fermenter has past the exothermic phase, another new one can be added and the probe switched to it. The passive/finished beer in there with it will go a bit below the temp SP for the active one, but temp control is not real critical at that point anyway.

Thank's for the help. What is the typical temp rise from exothermic activity?

ok, mods are done. moved the probe to the side of a fermenter, and also went ahead and made a support so that I can put 2 fermenters on the top shelf rather than the floor. I am going to store a bucket of sanitizer in the floor, along with some other random liquids that will act as a heat sink. The floor is also where the heater will need to go come winter. I set the swing back to the factory .5 degrees c, and it appears to be cooling much more predictably.

autobaun70 said:

Thank's for the help. What is the typical temp rise from exothermic activity?

Click to expand...

It varies a lot depending on how active the fermentation is. My experience has been somewhere around 3-5F when fermenting at 65F, but I've heard that it can be as much as 10F for very active fermentations. In general, the lower the fermentation temp is to begin with the slower fermentation is resulting in less exothermic activity. I tape the probe to the most recently brewed batch and then tape a folded up paper towel over it. Active fermentation is usually mostly over within a week and I never brew more often than once a week, so this works well for me.

The earlier post was correct on the temp rise. The difference between ambient air and the ferm vessel ranges between 3-10F. That is why probing the ferm vessel is easier than trying to adjust the ambient temp to keep the ferm vessel temp at the target temp, or worse yet, just setting the air temp to the target ferm temp.

Did you max out the compressor delay param?
It won't, or shouldn't, ever impact the temp control of the contents. It is just there to prevent activation of the compressor shortly after it has just run. This can happen for long door openings, the probe coming untaped, or when switching the probe between vessels.

cwi said:

Did you max out the compressor delay param?
It won't, or shouldn't, ever impact the temp control of the contents. It is just there to prevent activation of the compressor shortly after it has just run. This can happen for long door openings, the probe coming untaped, or when switching the probe between vessels.

Click to expand...

I did, now set at 10 min. Seems to be working great at this point.