I have a summit 570 kegerator which does not get cold enough. I bought the Johnson A419 - saw reviews everyone swears by it. I hooked it up, set at 32°F, the display reads 43°F and does not come on. I do not think it is bypassing the factory thermostat in the fridge - do I need to bypass it, and if so, how?
It sounds like you could be right - if the existing fridge doesn't get cold enough, then the thermostat is opening (disconnecting the circuit) above your target temperature, so the unit doesn't get cold enough. I'm assuming you've looked for some adjustment on the thermostat - most fridges have these.
So, if you have connected the A419 to the mains socket of the freezer, then the built-in thermostat still still be in play and will shut off the fridge too soon.
This thread here talks about the temp sensor being covered in ice prematurely, which is the reason they don't get cold enough. The fix was to improve the door seal, since that was letting in moisture causing ice buildup on the sensor.
This thread gives instructions on how to bypass the thermostat:
How do I bypass the Summit thermostat? There are two wires that enter into the fridge compartment and clip onto the thermostat. I am assuming one is 115 volt and the other tells the compressor what to do. If I splice these two wires together, will the compressor run continually? I can then let my Johnson Control thermostat control the system and hopefully get my pours down into the proper temps in the 30's. Right now I am pouring at 45 degrees, not acceptable!
And the reply:
You are correct that connecting the 2 wires of the thermostat results in it running non-stop. I don't think it's 110 volts at the thermostat more liKely it's a relay switch at much lower voltage but when they are connected the switch is in the on position. Your temp. controller will then be needed to take over the control of the compressor. If your unit is healthy it should be able to get below 29 F. the temp beer freezes at so be careful setting the temp on your controller.