Neff fridge internal temp too high before compressor starts

[trp]

We own a fairly old Neff fridge – E-Nr 621 358 822 – that is reaching an internal temperatue of 12-14 degrees centigrade before the compressor starts. The compressor will start without issue and bring the temperature down to a set level after several minutes. For example if the dial is set to 4 the compressor will stop at 4.9-5.9 degrees and if it’s set to 5 it will stop at -0.9 or thereabouts (too big a jump?). It will then stay off until the temperature gets up to the aforementioned 12-14 degrees and then start again. If the dial is set to the higher setting (lower temp) the compressor will start at a slightly lower temp, ie 12 degrees or so, so there does seem to be a vaguely working range but, as we now realise, the upper temp is way too high. The ‘only’ food issue we appear to have had is a couple of sealed bottles of milk going off very prematurely recently which prompted us to check what the internal temp should be, which was a bit of a shock.

Is this likely to be a faulty thermostat? I’ve read the guides and it seems that thermostats tend to fail in an on/off fashion, ie frozen fridge or no cooling atall – which this isn’t. Compressor fault? But the compressor seems to be working in so much as it comes on at a high temp then goes off at a low temp without any issue. I read that the compressor is/should be running 60-80{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} of the time – ours is nowhere near that.

I’ve looked at the thermostat phial and it’s not in great shape. It runs from the thermostat (branded Ranco K59) to behind the plate in a big loop before coming back out of the side of the plate and locked into a small depression in the plate secured by a large clip. It’s certainly not a smooth loop behind the plate and there are a few bends in it verging on shallow kinks.

Tim

[Luggsey]

Is the stat a capillary type with a copper bulb on the end or an electrical wire with a plastic bulb?
I can’t recomend you change anything electrical yourself but it does sound like a thermostat problem to me?

[trp]

Thanks for replying – it’s a capillary type with bulb. Having said that it’s all a bit moot now as, coincidentally enough, we took delivery of a new fridge/freezer today. I emailed the shop about which thermostat I needed and mentioned I hadn’t had a reply to my thread but that it didn’t matter as if it wasn’t the thermostat then it was beyond me and not worth the cost to get someone in. The person who replied looked at the thread and in no uncertain terms said it was the compressor. For c£25 I would have tried the thermostat if the answer was possibly or probably but that wasn’t the case and whilst we’ll never know now we’ve moved on. And ‘fairly old’ is an understatement. On taking down the carcass (the Neff was built in) the supplier label had a date of 1981 and I’ve no reason to believe the fridge didn’t come with it. So it was 40 years old (and I strongly suspect hadn’t been working properly since before we moved in nine years ago) – indeed an antique, as it was referred to, and no doubt time for us to enter the 21st century!

[Luggsey]

Trouble with refrigeration is its a bit of a black art with special tools unless its a thermostat fault!

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