Essentially Dead Beko Fridge?

[JohnW2]

Hi there,

I think I probably have a ‘dead’ fridge (probably something wrong with the compressor and/or the refrigeration circuit).

It is a Beko UL584APW larder fridge, about 7 years old, which has been working fine until very recently. As I usually try to do, when its warranty expired, I acquired a job lot of spares for the ‘electrical’ components (thermostat, compressor ‘relay', 'overload protective device' and start capacitor).

Recently, it started ‘not getting cold enough’, usually running at 7-11°C, regardless of the setting of the thermostat.

I first changed the thermostat and then, progressively, all of the other items mentioned above, but the behaviour remained essentially unchanged, at least in ‘bottom line’ terms.

What seems to be happening now is that when it is first switched on, it runs and drops the temp a fair bit, but then the compressor stops for a while before re-starting. When it stops, it is warm, but not particularly hot (certainly not ‘too hot to touch'). It continues cycling in this fashion, but the temp never gets below about 7°C, usually somewhere between 7 and 10°Cs. This seemed (to me!) most likely to be due to malfunction of the ‘overload protector’, but the behaviour did not change when I replaced it.

Whilst the replacements I have effected have not materially changed anything, one thing happening now which I do not recall having been the case initially is that when the compressor goes into one of its ‘off’ phases, the interior light does not come on when one opens the door. That seems odd, since I thought the overload device only switched off power to the run winding of the compressor.

Needless to say, I’ve run out of ideas - since there is now essentially nothing more that I could replace. I suppose that means that the problem is due either to an ageing compressor or to something wrong with the refrigeration circuit - neither of which I could do anything about.

Have I missed anything? Any thoughts about what is going on?

Kind Regards, John

 

[jj4091]

Have you tried varying the stat. up & down when it goes into it's "off phase" & is the 240 volts input still present ( I presume there is a suppressor that is accessible after the cable entry.

 

[Harry Bloomfield]

Insulation failure or low on gas?

+5 to +7C is the normal operating temperature of a fridge.

 

[ericmark]

My first test is the energy meter, if the unit be it fridge or freezer motor uses 60 watt, and the energy meter shows using 60 watt/hours per hour then clearly not switching off, then second test is temperature, if not switching off and a freezer shows less than -18°C (freezing point of brine) or fridge +4°C or wine cooler +16°C then many be thermostat faulty, but if above then likely lost gas.

I had a freezer rather small not switching off, it was actually sitting at around -24°C, but before I knew that tried to buy a thermostat or get it repaired, it seems no where I could take fridge to, all the repair people it seems were mobile, did not matter what the fault was, it was £60 to call them out, which covered first hour, parts extra, so it would be very easy for repair cost to exceed the valve of a non frost free freezer.

The more modern freezer even harder, with inverter drives in the main they are little more than soft starts, which since the motor does not shake its self on every start must help stopping pipes cracking, and reduce noise, it also means the energy meter can show when the de-frost cycle comes in, but as we move to larger units they alter motor speed rather than switch on/off, so only way to know faulty is to compare energy meter readings when new, to readings now.

I tried to use the annual energy rating, if 365 kWh/annum then 1 kWh per day, so if using 1.2 kWh likely OK, if using 2 kWh likely a fault. And it seems to work well.

However running all the time may mean loss of gas, but it can also means insulation damaged, I had an old fridge/freezer on maintenance contract since new, and it would seem to go wrong around once a year, I would transfer food, and defrost first, as the first time guy called out it transpired there was a build up of ice behind the divider stopping the fan from working, and most of the time, after a defrost it worked OK, but on one time I had not defrosted first, and the guy opened door and said uneconomical to repair, the insulation was damaged, where the ice had formed showed what had gone wrong, so it was replaced and used as a brew fridge for years after. It was OK as a brew fridge as it is the ice which transmits the heat into the freezer, so at 18°C ice does not form, so no problem, but it seems on switch on from warm the unit works great, but as the ice built up it would run for longer and longer, so likely the freezer was faulty from new, we just did not realise.

So when I bought the new freezers and fridge/freezers I used the energy meter, so I know how much they should use, so can easy compare now and see if performance is dropping off. The motor and inverter drive had a 10 year warranty but not the rest, so if and when it fails still not sure if worth repairing.

 

[JohnW2]

Have you tried varying the stat. up & down when it goes into it's "off phase"...

Indeed I have, and that does nothing. However, remember that, at least now, when it's in it's "off state", the interior light is not functioning, so I'm not convinced that electricity is 'getting anywhere'.

... & is the 240 volts input still present ( I presume there is a suppressor that is accessible after the cable entry.

The ('mains') input cable goes straight to the so-called 'relay' thingy plugged into side of the compressor (which, indeed, seems to be the only 'wiring centre' for the entire machine). There is, needless to say, still 240V present on that input cable at all times, but I don't know about 'beyond that'.

The thing about current behaviour that I find most difficult to understand is why the interior light is not working when the compressor goes into its 'off' state'. There are only three cables connected to the 'relay' thingy - the incoming mains, a 2-core cable going to the capacitor and a 3-core plus earth cable, presumably going to the light/thermostat enclosure. The latter has L & N connected directly to the incoming supply cable, so that 240V should always be supplied to the light/thermostat enclosure, and hence the light always work (the third core of that cable goes to the 'overload protector', and is therefore presumably the switched live from the thermostat). I've so far been totally unable to locate a service manual for this fridge. Does anyone know whether such a thing exists and, if so, where?

Kind Regards, John

 

[JohnW2]

Insulation failure or low on gas?

'Low on gas' is the sort of thing that I was referring to when I talked of a problem with the 'refrigeration circuit'. However, I don't really understand how 'low on gas can arise' (although it's something I hewar about) - I would have thought that if there were the slightest of leaks, the pressures involved that it would fairly quickly loose nearly all of the gas, and hence not work (cool) at all - but (as you mention below) mine is 'almost working'.

As for 'insulation failure' are you talking about thermal insulation? If so, I can't see how/why that could have arisen.

+5 to +7C is the normal operating temperature of a fridge.

Indeed. However, it's never getting below 7° - usually between 7° and 11°, most commonly 8°-9°. The issue came to our attention because 'milk was going off' far too quickly.

Kind Regards, John

 

[JohnW2]

My first test is the energy meter, if the unit be it fridge or freezer motor uses 60 watt, and the energy meter shows using 60 watt/hours per hour then clearly not switching off ...

I don't need to do that because my problem is that it IS 'switching off' (when it shouldn't)!

... then second test is temperature, if not switching off and a freezer shows less than -18°C (freezing point of brine) or fridge +4°C or wine cooler +16°C then many be thermostat faulty...

That is the opposite of my problem and, as above, it IS switching off - and, in any event, as I've said, the thermostat has been replaced without changing behaviour.

... but if above then likely lost gas.

Yes, as I said, I am reduced to assuming (by elimination) that there is something wrong with the actual refrigeration system. However, as I just wrote to \harry, I don't really understand how one can lose some gas without effectively losing it all- and my fridge is 'almost working' (can get temp down to around 7°).

Kind Regards, John

 

[Harry Bloomfield]

'Low on gas' is the sort of thing that I was referring to when I talked of a problem with the 'refrigeration circuit'. However, I don't really understand how 'low on gas can arise' (although it's something I hewar about) - I would have thought that if there were the slightest of leaks, the pressures involved that it would fairly quickly loose nearly all of the gas, and hence not work (cool) at all - but (as you mention below) mine is 'almost working'.

As for 'insulation failure' are you talking about thermal insulation? If so, I can't see how/why that could have arisen.

I had in mind that it had maybe lost a proportion of the gas, then resealed itself.

Yes, the thermal insulation failing - it can and does happen. Feel around the outer casing for cold spots. My theory - an air leak between outer and inner case, allows the insulation to absorb moisture, moisture which then freezes in the insulation. Simply leaving it turned off for a few weeks, might allow most of the ice to melt and evaporate, followed by sealing the leak(s).

 

[JohnW2]

I had in mind that it had maybe lost a proportion of the gas, then resealed itself.

Yes, I suppose that's the only way it could happen (and one does hear of 'partial; gas loss'), although I find it hard to imagine how that "resealing itself" could happen!

Yes, the thermal insulation failing - it can and does happen. Feel around the outer casing for cold spots. My theory - an air leak between outer and inner case, allows the insulation to absorb moisture, moisture which then freezes in the insulation. Simply leaving it turned off for a few weeks, might allow most of the ice to melt and evaporate, followed by sealing the leak(s).

Maybe. There are no obvious 'cold spots' and don't forget that this is a larder fringe, so there shouldn't be anything cold enough to freeze anything. In any event, an insulation problem would not explain the compressor switching off 'prematurely' (quite the contrary), let alone the interior light also becoming non-functional when the compressor stopped. It all seems pretty weird to me!

Kind Regards, John

 

[Harry Bloomfield]

I know next to nothing about fridges or freezers, other than basic principles, but your replies do seem to be pointing towards an issue with that relay/control thingummy not doing what it ought to do. My guess is that it is the soft start unit, come delayed start, come defrost control. Could you perhaps try bypassing that and then see how it performs?

 

[JohnW2]

I know next to nothing about fridges or freezers, other than basic principles, but your replies do seem to be pointing towards an issue with that relay/control thingummy not doing what it ought to do. My guess is that it is the soft start unit, come delayed start, come defrost control. Could you perhaps try bypassing that and then see how it performs?

It's what they call a 'relay' - actually a semiconductor one (I assume a triac or somesuch) which seemingly turns the compressor on when so instructed by the thermostat. However, when I replaced it with a new one, that made no difference.

The other thing I replaced is a thermal switch they call an 'overload protector' which although supplied separately, actually clips into the 'relay thingy' - the purpose of that seemingly being to switch off the compressor if it gets too hot. That's what seemed to be the most likely culprit, but, again, replacing it with a new one made no difference.

However, I know about as much about fridges/freezers as you do - so who knows?!

Kind Regards, John

 

[JohnW2]

It's what they call a 'relay' - actually a semiconductor one (I assume a triac or somesuch) which seemingly turns the compressor on when so instructed by the thermostat.

Not quite! I've been looking around, and it's simply a 'start relay (as I said, presumably a semiconductor one in my case), which activates the start winding of the compressor's motor at start-up.

The other thing I replaced is a thermal switch they call an 'overload protector', per one of the diagrams below ) - which although supplied separately, actually clips into the 'relay thingy' - the purpose of that seemingly being to switch off the compressor if it gets too hot.

That seems to be about right. The below two diagrams are typical of what one can find, the only difference being that one has the 'overload protector' (or "protractor", per the first diagram -) ) in the (presumed) Line path and the other in the Neutral Path. However, I've seen no diagrams which give any insight into how the light can go off when the compressor stops!

... none of which gets me anywhere

Kind Regards, John

 

[jj4091]

Have you tested to see if it is the thermostat that is switching the compressor off & not a loss of power, personally I would be thinking that you are losing the neutral line at. one of the components you have replaced. Or alternatively you have connected the light to the o/p of the stat. instead of the i/p & still have separate fault on the cooling circuit.

 

[JohnW2]

Have you tested to see if it is the thermostat that is switching the compressor off & not a loss of power, personally I would be thinking that you are losing the neutral line at. one of the components you have replaced.

Thanks for your continuing interest.

Testing is easier said than done, primarily due to 'access' issues, but I've been through that thinking process. Neither the original nor replacement thermostat should be switching the compressor off, since the fridge is not getting cold enough (with thermostat at 'coldest' setting'). If that's the case, it only leaves the 'overload protector' that could be turning the compressor off - and since that is just a 'two terminal device' (one 'in' and one 'out') with the 'out' only connected (directly, via a 'pin') to the compressor, there's no way that it could be affecting the light

Or alternatively you have connected the light to the o/p of the stat. instead of the i/p & still have separate fault on the cooling circuit.

That was my first thought, but I can't see how I could have done that. The entire light/thermostat assembling is connected to the rest of the fridge by a multi-pin (I think) mini plug/socket, so I can't have changed that. The thermostat itself has three terminals and, although I don't know what each one does (or why there are three), I matched the original wiring colour-for-colour - and, in any event, find it hard to see how 'getting the connections to the thermostat wrong' could, in itself, affect the light.

I think that, despite the difficulties, I'm going to have to try to do some 'testing', so I at least know what is going on electrically.

It's a fairly old (and cheap) fridge so if it had simply 'stopped working' I would have no qualms in simply replacing it. However, as well as having become 'an intellectual challenge', it is 'so close to working' that I feel a little hesitant/reluctant to throw it out.

Edit: to illustrate, it's just "done it". About five minutes ago, the compressor was running, the temp was 8.6° and the light came on when I opened the door. The compressor just stopped whilst I was standing next to it (temp 8.5°) and the light then did not work.

Kind Regards, John

 

[Harry Bloomfield]

If that's the case, it only leaves the 'overload protector' that could be turning the compressor off - and since that is just a 'two terminal device' (one 'in' and one 'out') with the 'out' only connected (directly, via a 'pin') to the compressor, there's no way that it could be affecting the light

Obviously (the interior light), suggest the problem is something towards the mains input side of the fridge - failing mains cable, fuse, 13 amp plug/socket. Beyond that - I would be tapping into various points on the circuit, taking them out to a terminal strip for easy access, then a neon indicator or two would soon track down where it is failing.