Samsung fridge/freezer issue -problem solving

[dishman]

I have this model: Samsung-Rl39wb

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The issues stemmed from leaving the door open, and it building up a large amount of ice.

Since then is has not worked properly, even after cleaning the ice.

I thought I fixed it at one point, after I uncovered a discreet iced up duct. After clearing that, it works fine for about a week, but ice ends up building up and blocking the duct once again and cutting off airflow to the fridge.

So, after a lot of reading, it seems to be down to either a faulty thermistor (it seems to have three) or a defrost system failure.

I just need a bit of help working out what part of the defrost system is at fault:

It seems a freezer like this has a background defrost to keep ice from building up, which turns on and off as needed.



My attention is drawn to the heater cover evaporator. Is that the heating part for the defrost function?



There is also that lower thermistor sensor which seems to be positioned in the location where the duct gets iced up.

I also found this video which is the exact same model, which is hard to follow with auto-translated subtitles. But he seems to suggest there is an issue with the defrost function, but it looks like he is replacing the whole coil unit.



This is the circuit diagram, but this seems to suggest there are 3 heating elements? I'm not sure.

 

[foxhole]

Does it or did it make rapid clicking noise when door was opened?

 

[dishman]

Does it or did it make rapid clicking noise when door was opened?

Not that I can tell. Certainly nothing I notice compared to how it normally operates.

It clicks once when I open it and once when I close, but this sounds like just the actuator for door.

When I last fixed it, it seems to work perfect for a week, but it just lets too much ice build up near the bottom vent. So I certainly think something is not activating the defrost or anti-frost component to keep it frost free.

 

[foxhole]

Not that I can tell. Certainly nothing I notice compared to how it normally operates.

It clicks once when I open it and once when I close, but this sounds like just the actuator for door.

When I last fixed it, it seems to work perfect for a week, but it just lets too much ice build up near the bottom vent. So I certainly think something is not activating the defrost or anti-frost component to keep it frost free.

It does not have a defrost component , the fan moves the air to the rear where it condenses and run thru a small drain to rear.Usual problem is an obstructed fan (ice) and/or a blocked drain hole .

 

[dishman]

That's always thought, but for some reason, ice is building up there, as if there is a stall in air flow.

If there is no heating component at all, what is this component?


It comes up as being this:


Trying to work out what it does. It's not near the ice build--up location.

 

[ericmark]

Every so often I test my freezers, I was testing the chest one, now moved to upright one.

I can see the peaks where the defrost heater has come on, but it does not seem to be at a regular time, some days no peak, other days two peaks, so not sure how is senses when required, previously we had a Hotpoint, which was in the end shown to have faulty insulation, however the reason it took so long to find the fault, was I would defrost it first, there was a partition which I could not easily get behind, and the main problem was the frost would foul the fan behind the partition, and this in turn started a clicking.

So I would empty the freezer into cool bags, and then place a fan in the freezer to blow air into the freezer, no extra heat, just a fan, it would first melt ice in main compartment, then start melting ice behind the partition, it took a long time, but once water dried up, we would assume free of ice, and refill it and turn back on, it would normally go around 6 months before failing again.

We would call the maintenance contract we had, each time they would change some small part, but one time I had not got around to defrost first, and it turned out the insulation was damaged, likely from new, where we bought it they would sell repaired machines cheap, and I think the shell had been damaged, they changed the panel, but not the insulation behind the panel. So ice would build up in the insulation, and the ice conducted the heat into the freezer. Once ice melted, then air is a better insulator, so it was OK until ice built up again.

We got an allowance on the old freezer, so bought new, and it did another few years in the garage as a brewing fridge.

So step one is use a monitor to see if the defrost kicks in, step two is a very good defrost, step three needs someone who knows the product, as soon as the engineer saw the way the frost had formed, he knew the problem, he said to stop using it, and they would arrange a refund based on the age of the appliance, yes I how are you going to stop using it? Can't do that until you get the replacement. But I would have never found the fault myself.

 

[dishman]

It does not have a defrost component.

That is what I always assumed, but it is actually not the case.

I've worked it all out now, with thanks to a very helpful youtube video.

The defrost element is integrated to the cooling evaporator. This freezer also has a secondary pad heater to keep the fan frost free.

Basically the freezer defrosts intermittently using those elements to keep the vents free and the circulating fan keeps frost build up to a minimum.

It has three thermostats, one for the fridge, one for the air temp in the freezer and one right near a freezer vent where frost builds up first for the defrost.

It also has a thermal fuse.

In my case, it looks like the main heating element is fried. I am getting no resistance reading from it on the multimeter. Whereas I am getting continuity on the thermal fuse, and the thermostats give a healthy reading. The secondary pad heater also gives me a good reading.

So, looks like, while the fridge works, the defrost component means it will keep blocking up after a while.