Chiller temp fluctuations.

[Puds]

I’m now using a tall single-door Coke fridge & it has held the temperature at a steady 1-2c, not changing if I’d got just one muntjac in there or a roe along with a couple of munties.
However, last week it decided to go up to 9c on full chill and resulted in me unfortunately chucking out two muntjac carcasses that were in there.
Any idea what could have caused this/how to fix it?

Photo to show how it’s commonly set up.

 

[75]

My guess would be it either needs re-gassing or thermostat is knackered.

 

[weblyish]

I assume you checked all the most obvious

The door was shut
The temp was accurate and correct
No power cut/unplugged etc
Radiator is free of obstruction dust etc
Fan (if applicable) is running free


After that if it seems to be chilling sometimes and keeping sort of cold then it can be thermistor/controller which are usually fairly easy to replace yourself

 

[Puds]

I assume you checked all the most obvious

The door was shut
The temp was accurate and correct
No power cut/unplugged etc
Radiator is free of obstruction dust etc
Fan (if applicable) is running free


After that if it seems to be chilling sometimes and keeping sort of cold then it can be thermistor/controller which are usually fairly easy to replace yourself

I’m presuming the radiator is the bit at the bottom behind the plastic grille? If so, it’s somewhat dusty so I’ll give it a vacuum out.

 

[weblyish]

I’m presuming the radiator is the bit at the bottom behind the plastic grille? If so, it’s somewhat dusty so I’ll give it a vacuum out.

Maybe at the back?
Usually lots of thin pipe or fins
If it is at the bottom it may have a fan to circulate air in which case check that is working

The radiator should be noticeably warm when the fridge is running if not then something major is wrong

If you hear some humming from the compressor (not any fans but the big lump of machinery at the bottom) then it probably needs gas if it is running but not getting cold - gas is cheaper than even a second hand drinks chiller if you can find someone local)

If you hear no humming then it might be a compressor issue. Which is a bit problem unless it is due to a faulty thermostat or something as above (compressor replacement is definitely more expensive than a second hand replacement fridge)

 

[Puds]

I’ve just been to vacuum it out & turn it on to give it an empty test run (am stalking tomorrow evening) and it’s definitely getting colder & there’s a humming noise from it, as well as the top fan spinning up. I’ll see how cold it is in the morning & take it from there.

Thank you for the advice

 

[David Barker]

I had the same and found my cheep inside cabinet thermostat was the prob.s.

 

[Puds]

I had the same and found my cheep inside cabinet thermostat was the prob.s.

That sort of thing? https://amzn.eu/d/8HsULJn

 

[David Barker]

Yes mine was the expensive £4.99 one lol. Now changed for a decent one like said above all cleaned of crap and working fine fingers crossed.

 

[Puds]

Finally got around to looking at the chiller and have dropped the thermostat out.

Anybody know if the brown/red wire in the foreground should be attached to either of the empty tabs? It was loose when I dropped the panel down.

 

[VSS]

Is one of those tabs noticeably cleaner and shinier than the other?

 

[weblyish]

yes definitely, there are usually minimum 3 spade connections, a probe connection and an earthing wire for the thermostat unit

if you are comfortable doing so carefully and without killing yourself I would turn it on and see which is live to determine the power IN, the rest should be obvious
you could also try tracing the wires back from the mains input to see which is power in

(there may be more connections if you have defrost unit, eco setting or freezer but your looks like straightforward fridge unit from here)

 

[75]

That doesn't look original wiring to me - those blue crimps top of the picture were very unlikely to have been fitted in the factory. Plus they have brown/red wire in and black wire out (one in the foreground). I suspect someone has replaced that thermostat before and extended the wires to make it easier to access.

 

[Puds]

Is one of those tabs noticeably cleaner and shinier than the other?

The ‘in’ tab looks like it’s got slightly more shine on the top edge but not much.

Multimeter isn’t showing any voltage on the red/brown wire, and it’s turning on/fan spinning without that wire connected.

 

[VSS]

The ‘in’ tab looks like it’s got slightly more shine on the top edge but not much.

Multimeter isn’t showing any voltage on the red/brown wire, and it’s turning on/fan spinning without that wire connected.

I was just thinking that if one was more shiny, not tarnished after being exposed for a while, it might indicate that the connector had recently become disconnected from it (eg, been accidentally pulled off while you were fiddling about).

 

[Puds]

yes definitely, there are usually minimum 3 spade connections, a probe connection and an earthing wire for the thermostat unit

if you are comfortable doing so carefully and without killing yourself I would turn it on and see which is live to determine the power IN, the rest should be obvious
you could also try tracing the wires back from the mains input to see which is power in

(there may be more connections if you have defrost unit, eco setting or freezer but your looks like straightforward fridge unit from here)

Would it still turn on without the power in connected to the thermostat?

 

[Puds]

I was just thinking that if one was more shiny, not tarnished after being exposed for a while, it might indicate that the connector had recently become disconnected from it (eg, been accidentally pulled off while you were fiddling about).

I’ve plugged it onto the ‘in’ tab & turned it on, and so far nothing’s blown up/electrocuted me. The fan is spinning & the back wall of the fridge feels cold, which I’m guessing is a good sign.

Edit to add I’m getting a low voltage off the ‘in’ tab now, fluctuating between 5-8

 

[Puds]

Just bothered to read the sticker after screwing the plate back on… am I being thick or is there another thermostat I’ve not found yet?

 

[75]

It may be the old thermostat was knackered and has been bypassed with a new one (hence new wiring). I don't think it's uncommon to do that.

 

[VSS]

It may be the old thermostat was knackered and has been bypassed with a new one (hence new wiring). I don't think it's uncommon to do that.

That is exactly the case with my spare chiller.