Liebherr GN2856 nofrost

[BrokeLiebherr]

Liebherr GN2856 Nofrost upright freezer
Index 20/001
SN: 9987596-00

Hello, I’ve got an issue with a stand alone freezer that maybe this forum can help with, maybe they’ve seen before. It started getting warmer, about -10 with alarm, to about -1.

I emptied, opened and unplugged for a couple days. Not much frost, no frozen block of ice. Plugged back in and after 6 hrs with a couple gallons of water in it, had gotten down to -7, but no colder.

All coils are clean, no leaks that I can see. Compressor starts right up; within 2 minutes evap coil is cold, few minutes later it is frosted.

I’ve tested the thermistors that I can get to. One stuck in the evap coil, and one in the front of the cooling module. At 55 degrees ambient, evap sensor at 6K, the other at 6.16. In freezing water, the evap sensor read 13.7K ohms, the freezer compartment at 14.17K ohms. Is there another I’m missing?

The fan motor doesn’t seem to be getting power, though I don’t know if I was able to trick the freezer into running it. I put the sensors back in and ran it for 10 minutes at least with the door switch closed, no power to fan. Tried putting the evap sensor in ice water too to no avail.

Measuring acoss the motor leads give me an open, no continuity. That would tell me the motor is bad, but you would think I would still get power to it.

Anyone know how to get the fan motor out? Do I have to drop/pull the evaporator? There is a small metal clip to keep the fan motor in position, but removing this does not give me enough clearance to remove it. I had to take a break, I was going to turn it into scrap.

fan motor?
thermistor?
PCB?
junk?

[ELDAR59]

Re: Liebherr GN2856 nofrost

hello, it does sound like your problem lies with the evaporator fan not running and circulating the cold air around the cabinet.
if the fan is one with a pcb,(it will be housed in a white plastic box) then you wont get a resistance reading from it.
the fan is switched on by the pcb, but the pcb relies on an impulse from the evaporator sensor.
in order of probability, given the sysmptoms you’ve described, id say the problem could be:-
evap sensor, although id be tempted to change them both while I was in there.

pcb.

fan.

fan faults are more common than pcb faults, but as you’ve said, there is no power to the fan motor. do bear in mind though, the evap has to be down to temp before the pcb will give the fan power. obviously the door has to be closed too.

[BrokeLiebherr]

Re: Liebherr GN2856 nofrost

Yes, the fan is not working. The evap/compressor seem to be cooling fine and I see no evidence of coolant oil anywhere. Both sensors move immediately from about 6K to past 13K ohms when placed in ice water. Is there different/intermittent faults with these? How much do these sensors run. Might be expensive for a troubleshooting step.
I did have the magnetic door switch closed for at least 15 minutes when running with no fan power. Is there another switch I’m missing?

Thanks for pointing out the resisance on the motor, I don’t think I would have caught that. My next step was to remove the plastic evap cover and try to get the motor out.

Does anyone have any steps/checks to rule out the PCB?

Thanks

[ELDAR59]

Re: Liebherr GN2856 nofrost

the sensors are not expensive and by far the cheaper option of all the rest.
you can obviously simulate the door being closed by offering a small magnet to the reed switch. that way, with the door open, you would be able to hear properly. you could also check for voltage at the fan, thereby confirming your diagnosis.
other than on the board, there isn’t another switch for the fan and in practice if the system is ok, it should run after 15-20 mins or so.

[BrokeLiebherr]

Re: Liebherr GN2856 nofrost

I’ve already checked the voltage (none) and resistance (open) at the fan; of course I have it apart with the door open. My concern is if I am putting the sensors at the right temp that the PCB will turn the fan on. I wasn’t sure if the evap sensor would get cold enough with me having the door open. I’ve read that the evap sensor has to be a couple degrees warmer than the temp sensor. I’ll shove it all back in there and run it for 1/2 hour; I think I can figure out which terminals run the fan. That way I can check it with the door closed and hopefully at right temp. If that don’t work, no power; I guess I’m looking for a couple sensors. I think I’ve only got about $150 into this freezer. It would be a shame to junk it; it’s been the best freezer I’ve ever owned.

[admin]

Re: Liebherr GN2856 nofrost

Hi

The evaperator requires to be at approx. -15 before the fan will come back on.The evaperator sensor is the most likely defect but when its changed leave it running overnight so that it gets down to temperature.

Opening and closing the door will never get the fan to switch on.

Bryan

[ELDAR59]

Re: Liebherr GN2856 nofrost

Hello, as discussed earlier, you won’t get a resistance reading from the fan. You’ll also not get voltage at the fan with the door open.
The evaporator sensor is always going to be colder than the air sensor because it measures the temperature of the aluminium evaporator and not air.
It’s the air sensor that has to be a couple of degrees warmer.
Of course the evaporator should be cold enough with the door open. Set it running, leave it for a good hour or two and then check it.
Part number of both sensors is 9590148

[BrokeLiebherr]

Re: Liebherr GN2856 nofrost

Door opened/closed shouldn’t be an issue for fan voltage as long as the door switch/reed switch is closed, correct? That is what I meant; you’re going to have to have the door open to do fan voltage checks at the fan unless you cut a hole in the back of the unit. I messed up my sensors in my response. Of course I know that the evap sensor has to be the colder one. That’s the first thing I tried, to put that one in ice, door switch jumped for 20 min, still no fan.

I put all the sensors back in their orig positions a few hours ago and turned it back on. I can do some voltage checks on the pcb without opening the door. It has been a few hours now, so I hope it’s working, or at least trying to turn the fan on.

Thanks for the part number; I imagine that this is where this is going. I just wish that one of them didn’t move at all and was a more definitive “bad”. I hope there is a source for the parts over here in the colonies.

[ELDAR59]

Re: Liebherr GN2856 nofrost

I saw the reference to $ but assumed it was a typo.
whereabouts are you?
is the appliance 240v?

[BrokeLiebherr]

Re: Liebherr GN2856 nofrost

Nope, no typo.
I’m in Missouri, USA.
This site was one of the few places that looked like they still sold/serviced Liebherr.
I bought this thing used a few years ago in Germany.
It is 240v and right now I’m running it on a step up transformer.
Been running fine for about a year in the US.

Quick update- turned it back on last night, adjusted temp to -15. No food in it.
This morning I see it is at -15; didn’t have time to stop so I returned in about a half hour.
Still at -15. Went over to it and I can hear the fan running. It is noiser than I remember it being. When I bought it, I don’t think I ever heard the fan, and just barely hear the compressor buzz. Anyway- I opened door, I can hear the fan spin to stop, again not too healthy; close door it starts up again. So maybe I’ve got a fan issue and not a sensor issue? A quick search on ebay brought up a couple sensors in NY; thought the part numbers didn’t match. I’ll pull the evap down again, make sure that a wire didn’t move into the fan. The front of the shaft looked like it was in a rubber grommet. I wonder if it would help to lube that with something.

[BrokeLiebherr]

Re: Liebherr GN2856 nofrost

Update- I let it run a few hours more, stable at -15, fan was not running.
I opened it up for a second, then closed it up. Fan started right back up.
I then opened it up, took down the evaporator and insulation so I could get a good look at the fan, and closed the door switch.
Fan comes on, but has this high pitch squeak/squeal to it. Moving it by hand, I can’t feel any interference with the housing. I think it is a lot noiser than a fan that should run almost constantly should sound. So I’m leaning towards the fan/fan bearings. Is there any repair to this component? I’m not even sure right how how to get it out.

[BrokeLiebherr]

Re: Liebherr GN2856 nofrost

I took the fan out. Turns out that when the metal clip is removed from the fan bracket, and the fan blade is pushed off, there is enough clearance to twist the fan motor on the rubber grommet and remove it out of the bracket. I removed the motor out of the white plastic cover, and then was able to take the motor apart. Simple AC brushless motor. Looks the the rotor was starting to rub on the side. I greased up the bushings for the rotor shaft and put it all back together. The freezer ran down to -15 no problem, and the fan worked for a few days without making any noise. However, the fan squeak and rumble returned, and I imagine that it is not far from locking up, which I think is what happened in the first place. So I’m going to try to verify the right fan motor to buy. I hope this helped some of your readers.

[Author]

Posts