How do fridge freezers ever work?

There's a lot of complaints all over the internet.

So you're saying it's incapable of cooling the freezer too much?

Which might not happen if you don't heat your kitchen, or it's in a utility room or garage.

Having them together can be physically useful, otherwise I'd need to stack them and hope one didn't fall off.

Not at all, quite a few are. Replaced a freezer in our integral garage several months back and found several to pick from - got one from John Lewis. Middle daughter wanted one a month or so back, also for garage, John Lewis again- this time an up-right freezer (ours is a chest freezer).

When we replaced our kitchen, I check the fridge/freeze that we had in the kitchen was ok for the garage, it was, and it has been working there ever since (we use freezers and fridges a lot, even with just two of us).

Ones which work down to 10 deg C are not at all uncommon.

Sure, redesign what works or 99.9% of people into something more complicated and expensive for the 1% of customers that might need it. There are fridge/freezer units with two separate compressors, if you want to pay for it.

They could combine the compressors into one, if

Fridges for decades have had a fan controlled by a thermostat that moves cold air from the freezer to the fridge compartment, as needed. Why fix what's not broken?

I've never had anything too frozen, have you? I know even decades ago fridges had a small fan that moved cold air from the freeze to the fridge compartment, as needed, to maintain the fridge temp.

Who has a kitchen so cold that the fridge running is an issue? Never seen one.

Then you buy a unit that's rated for that environment. I know people here in the NYC area that have them in their unheated attached garages with no problems. I have my freezer in the basement, so it's not an issue.

Why would it be impossible? Sounds quite simple to me. Two refrigeration circuits with an electro valve. Even cheap dehumidifiers have that, a reversing valve that's used to defrost it.

I don't know if mine does this or how effective it is, but it seems to cool the freezer with the compressor, then blow air from one compartment to the other to get the fridge cool. I would design this so the fan and compressor were independant, with seperate thermostats, but I've not noticed the fan and compressor come on individually, and a quick glance of the circuit diagram on the back (not for this purpose) as I was positioning it, I'm sure I remember only one stat. It wouldn't have cost much more just to add one stat!!

Correction, I just found another stat in the freezer compartment, there's one in each. Yet it will still only run the compressor and fan both at once. They must be wired up a really pointless and stupid way.

I assume this is a frost-free freezer too?

I have come across this type, where cold air from the freezer is piped into the fridge on demand. I would say this type should still work at low temperatures since the freezer temperature becomes the 'master'.

Yes.

I'm not sure without taking it apart and physically looking. The circuit diagram on the back (I just pulled it out to check) shows one compressor and one fan wired in parallel, and it also shows only one stat. It's a rather basic diagram and the connections to the defrost heater don't even make sense - it appears to only work if the main stat is calling for cooling! And I know there are two bimetallic stats (one in each compartment, and as I turn them I hear and feel the physical click). I've never observed the fan and compressor running independantly, they both come on simultaneously when I turn either of the stats to a colder setting. Also, according to the manual and from looking inside it, there appears to be two seperate circulations of air, one in the freezer and one in the fridge, they're not joined up. Perhaps air circulation is just for even cooling and/or not freezing food to the coils at the back of the fridge, which are hidden inside the air vents. I can only assume the two stats are in parallel and either will make both compartments cool down at once. This would mean at low ambient temperatures, the fridge would freeze up, unless it uses the defrost stat to warm it back up? It really looks like the designer was stoned when he made this thing.

On Monday, October 29, 2018 at 1:17:33 PM UTC-4, Undersized hippopotamus wr ote:

cool the freezer with the compressor, then blow air from one compartment to the other to get the fridge cool. I would design this so the fan and comp ressor were independant, with seperate thermostats, but I've not noticed th e fan and compressor come on individually, and a quick glance of the circui t diagram on the back (not for this purpose) as I was positioning it, I'm s ure I remember only one stat. It wouldn't have cost much more just to add one stat!!

one in each. Yet it will still only run the compressor and fan both at on ce. They must be wired up a really pointless and stupid way.

Why is it pointless and stupid? These fridges have been working for decad es, maybe 100 years and they work. I also know people who have taken an old garden variety fridge and put it in an unheated attached garage and it work s. What exactly is your problem? And since you're obviously still trying to figure out how they actually work, how many thermostats they have, how they control temp, don't you think it's a bit premature to declare the designs stupid? My new fridge pulls 90W when running, less than half what the old one pulled. It maintains perfect temp, in both sections. I have no compla ints.

What about someone who goes to visit relatives for Christmas, and switches the heating off in their house (or turns it down to 5C for frost protection), but leaves food in the fridge and freezer for a week? Manufacturers really shouldn't make stupid assumptions about the habits of the consumer.

Look up fridge freezers in garages on google and you'll find that they can't tolerate low ambient temperatures. With a rewiring, this one could. One stat could run the freezer as though it was a normal standalone freezer. The other stat could suck air from the freezer to cool the fridge when necessary. One fan, one compressor, two stats, as it already has.

They realise that it works much better to have the fan working when the compressor is working and use the second stat to decide if the fan needs to run faster when that section needs more coolth.

In other words the compressor comes on when either section isnt cool enough and the fan determines which gets cooled the most, presumably by the difference between the two thermostats and how far each is from its set point.

Not necessarily if the refrigerant used gets too gluggy to work well at the lowest ambient temps. There are clearly two factors that determine if the freezer section works well at the lowest ambient temps.

I'm inquisitive, I just have to know how this thing works, and if possible I'll rewire it and improve it. When I have the spare time, I'm dismantling it! This is a DIY group after all!

That's how frost free has to work, the coldest part is outside the fridge and freezer compartments and air from outside is drawn over that, with frost forming on that, outside the compartments, with cold air being blown into both compartments as required.

When the compressor isnt running, the frost melts and ends up in the bowl on the top of the compressor where it evaporates.

With my frost free separate fridge, in the most humid weather, when you close the door after opening it, you can hear a gurgle as the air in the fridge comes out the tube that has the end of the tube below the water level in the bowl on the top of the compressor.

There must be some way of varying the amount of cold air each compartment gets, otherwise the control of the temperature at the low end would be very bad in one compartment.

No, because at low ambient temps, only the freezer section thermostat would be turning the compressor on, and less often than at the highest ambient temps seen in summer.

There is no defrost stat in a frost free system. You only get that in a cyclic defrost system.

In reality you don't understand how they work.

You don't know that the compressor will still work well at that lower temp.

Not all of those work well at the lowest ambient temps.

And it works fine the way it is.

Not in the first para of yours you didn't.

Not possible with that one.