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brewmedic43 05-25-2012 04:03 AM

Johnson A419 help
I wired me new temp controller to my old chest freezer and after figuring out why the dang thing kept tripping the breaker I had a question pop up. Nowhere in the literature could I find anything on the subject. The wiring did not appear to me to bypass the existing thermostat, so with that still in line of the wiring, what "temp" should it be set at? The freezer is a Gibson elite 8 that has a rotary style thermostat that goes from off to coldest with about 8 settings in between. I first attempted to just barely turn it on but it still froze solid. I set the temp controller to 64* with a high set point of 68* and a delay of 10 minutes. Anything else I should do??? Thank y'all for the help. :mug:

Homercidal 05-25-2012 01:37 PM

Generally the device should be turned to the MAX COOLING position. The reasoning is that you always want the device ready to turn on whenever the external controller turns it on.

If it's turned down to far it might not kick on even when the external controller switches on.

The Johnson is a bit hard to configure IMO, until you get a good understanding of how it works.

There are 2 sets of jumpers. One switches it from HEAT mode to COOL mode. Obviously you want the COOL mode, so it know which direction the temperature is supposed to go when the setpoint or offset is reached.

The other selects either CUT-IN or CUT-OFF. Cut-IN says that when the setpoint is reached, turn the relay on and start cooling (if you have it in cooling mode..) and keep cooling until the offset is reached. Cut-OFF says that when offset is reached, turn on the relay to start cooling until the Setpoint is reached.

Remember that the cut mode matches the setpoint. So cut-in at the setpoint, or cut-off when the setpoint is reached.

It sounds like it's not in cooling mode to me. Or the relay is defective.

brewmedic43 05-26-2012 01:45 AM

Thanks Homer, I will try that.

Junkster 05-26-2012 12:17 PM

Freezer operating temperatures are generally around 0 or less, so the factory control will probably always be calling for cooling if you're running the box in the 60's - but, yeah you might as well dial it to "MAX".

Be aware also that if the freezer has a defrost timer (it probably does), eventually it's going to stop the compressor for a period of time even though your external controller is supplying power to the unit. After the defrost time period has elapsed it will then resume normal operation and cycle on the controller.

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