Mini Refrigerator broken

Hi,

has anyone heard of or does anyone think a Johnson Controller thermostat set at a 1 degree differential could break a mini fridge? I am trying to understand why my fridge is broken quite early, and I suspect it might have to do with my 1 degree differential turning the fridge on and off too frequently.

Any opinions on this?

Thanks,

Dara

With a mini-fridge you should be able to dial in the temperature pretty accurately with the built-in temperature controller. If you are going for warmer than normal fridge temps it should run the compressor less when you have your Johnson controller hooked up.

How often was the compressor cycling compared to when you ran it without the controller? How old is the fridge? Did you drill any holes in it? Does the compressor still run and just not cool the inside, or does it never kick on?

1 degree might be a little tight, I run my keezer at 3 degrees differential.

Hey,
It's about 6 months old,off Craigslist.it worked fine for months.I didn't drill a hole-the cable is small enough that the insulation on the door just wrapped around it when I.closed the door.I would guess it cycled on about half the time.maybe not drilling a hole was the cause.it doesn't power on at all now.even the light on the fridge does not turn on

probably a silly question but have you tried anything else on the same outlet or plug in? Any fuses or breakers on that line or refrigerator (i'm by no means an electrician of any kind).

hi,

the power from the outlet is on - the johnson controller still is powered on. That was how I noticed something was wong - it said 66 F one day when I checked!

dara

i'm guessing this was a used fridge that you got off CL 6 months ago, or is it now 6 months old? do you know the manufacture date?

Dara said:

hi,

the power from the outlet is on - the johnson controller still is powered on. That was how I noticed something was wong - it said 66 F one day when I checked!

dara

Click to expand...

Just thought I'd ask ... I myself have been know to over look "easy" things before.

If the temperature controller is worth it's salt, it should have an anti-chase/anti-osculation delay circuit.

All good aircon units and all good boilers have them. Basically it prevents the scenario where by:

Temp hits trigger.
Circuit shuts off cooler/heater.
Temp immediately drops below / rises above trigger.
Circuit turns on cooler/heater.

and.... it osculates every few seconds indefinitely. With a gas boiler this can be dangerous as the boiler releases a small amount of unburnt gas before lighting, so if it's relighting 5 times a minute it could gas the occupants. For an air con unit, it can break the thing, as the frozen humidity on the cooling fins will be like snow, switch the unit off and it will start to melt. Switch it back on immediately and it sets into ice. Thus an air con unit will not restart for at least 1 minute after it last shut off, allowing the melt to complete and the water to drain into the humidity bucket before firing up again.

Hi Paul,

ye the controller is good - it won't turn back on until the temp goes bove 1 degree above the target, e.g. I set it to 45, so when the temp goes to 47, it cools the fridge to 43. So it doesn't go on and off all the time. I opened the back of the fridge up, but the circuit board shows no obvious burn outs or anything, so I am just gonna toss the thing without knowing what happened.

I am not sure when it was manufactured, but it was bought new about a year ago, but it is a NuCool dorm fridge which doesn't have a compressor at all!

dara