Johnson A419 Temp Controller Problem

[trub quaffer]

Just got controller new a couple of weeks ago. It worked fine when I started using it to control fermentation temp of a lager but since I started increasing the temp in the fridge for the diacetyl rest it's wigging out on me. It will run for a few minutes, then it shuts power to the fridge and the display starts alternating between "asd" and the temp (57F). It does this for the asd period, then the power comes back on for 1 second, the display shows 55F and then starts alternating between "asd" and 57F again. It will do this 3-5 times before it will mantain power to the fridge for any time at all. It is mantaining a steady temp but obviously is not operating correctly. I have the probe sandwiched between the carboy wall and a piece of foam insulation. I have the differential set at 1 since the probe is measuring the temp of the beer and not the ambient temp. I did have the asd setting at 1 minute but have recently increased it to 7 to decrease wear and tear on the condensor. Anything I could be doing that is causing this abnormal behavior or do I just have a defective unit?

 

[Catt22]

IIRC, having the Asd set the same as the differential causes a conflict with the result you describe. Try setting the Asd to the max 12 minutes and the differential to 4 or 5 degrees. I'd also suggest reading the users guide info that came with the unit. It has information on the proper settings and how to use them.

When the display alternates between the Asd and the temp, it means that the Asd function has been tripped and it will stay in this mode until the Asd time has lapsed (in your case, for one minute as you had it set initially).

 

[trub quaffer]

I reset the asd to 12 minutes and set the differential at 5F and the unit seems to be working fine. Leaving the differential at 5F is not really an option the way I have things set up since the probe is monitoring the beer temp and not the ambient temp. I don't really care what the asd is set at since the condensor shouldn't need to come on more often than every few hours. I guess I'll just leave the asd at 12 and move the differential back down to 1 and see how things go.

 

[D-Ring]

I had the same issue and did the same thing.

 

[Catt22]

The 12 minute setting for the Asd will be fine. If the power fails for some reason, the fridge won't gain much temp in twelve minutes and it will be easier on the compressor if there's something else causing it to go into that mode repeatedly. I have the probe on mine in the air and a separate digital thermometer montoring the fermenter temp with the probe for it attached to the side of the fermenter and covered with some bubble wrap. I adjust the controller on the basis of what the separate thermometer is reading and I have the differential set to 5 degrees. The monitoring thermometer stays very steady in this configuration. Actually, I also have a couple of the analog Johnsons that are preset to a 3 degree differential, but they perform about the same. I do have muffin fans installed in all my freezers and fridges except the fridges that already have a fan from the factory which many do.