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I believe that model is controlled by an integral electronic board and a sensor, so slightly confused how a non exsistent thermostat could have been replaced.
If the whole of the rear wall freezes over we can rule out a weak compressor and gas issue, which only leaves the most likely culprit the sensor or the board which is possible but probably not.Having dug the back out of one years ago, they glue the aluminium half round pipe to the innner wall from top to bottom on a thin metal plate then add additional tape and a plastic cover over the pipework serpentine and the whole lot is then buried by the pumped in insulation foam.
I have seen this issue and the ones I saw it was down to the fridge evaporator losing gas and the pressure of the gas inreaed as the fridge warmed and caused the rear wall to expand, total right off, not fit for purpose etc etc sale of goods act etc etc.
Remove control knob, and light cover, the branded trim unclips at the rear and is slotted in near light switch and you will then find three fixing screws.
The thermostat housing requires removing and then refitted 2-3mm inwards on right hand hinged doors, it may require a new light swith if damaged.
Well done turbafan, that was the other version listed in my previous post that Liebherr also used, the end code is 003 and not 001 but this could just be a production date code.
Hi Peter,
Firstly I had another Engineer in Somerset try and purchase an obselete thermostat from this company in Brighton without success, no response to emails and not anwsering phone calls, so dont hold your breath on being able to get the 6151086 as I have preiously advised is a Ranco K59-L1287, I have full access to the technical specifications etc on all Liebherr parts etc as a service agent for them for over 23 years.
With this I can confirm my earlier statement on cut out and cut in temperatures that Liebherr require from the thermostats they fit to individual cabinets.
I can only assume your fridge does not have any compressor or refrigerant issues if at certain times it is reaching temperature, the thermostat will stop the compressor relative to the setting at the required temperature as measured at the end of the capillary tube fastened to the rear wall of the fridge eaporator, The rear wall will go through it’s defrosting period untill the temperature at the capillary end reaches 3.5 degrees plus or minus 1.1 degree.
Room ambient temperature will play a part in how long the fridge remains in defrost until the cut in temperature can be achived, Cold rooms means it will be off longer and can cause higher interior temperatures in the fridge.
You can lower the cut out temperature on your dial, but the cut in remains the same and cannot be adjusted from it’s preset temperature of 3.5c + – 1.1c, which should then give you an average temperature in the fridge of around 5c but this varies from the bottom shelf to the top shelf.
Tony.I can not confirm the thermostat is your problem without being there to check the thermostat cut in and cut out values, the thermostat 6151087 has a much lower cut out temperature compared to your original and has a higher cut in temperature after defrost but has the same capilary length.
Original cut out on maximum is -23c and -8c on warmest and a constant cut in temperature of 3.5c plus or minus 1.1 degree.
The 6151087 cuts out on maximum at -29c and -18 on warmest with a constant cut in of 5 degrees plus or minus 1.1 to 2c.
I would not advise fitting a 6151087 as you will probably have food freezing in the fridge.Hi,
Your KI 1840 index 22-147 is now 23 years old and unfortunately the thermostat part number 6151086 is no longer available with Liebherr.
It is listed as either a Ranco K59-L1287 or a K59-H1300 both versions were used on this model.
It may be worth searching the internet if someone has old stock of one.
It must be noted the thermostats have a constant cut in temperature of +3 degrees regardless of cut out setting ie coldest (7) or warmest (1) on dial and the capillary measures 900.
So you cannot just fit any type of auto defrost fridge thermostat as these generally have a much higher cut in temperature, and will not improve your problem.
Tony.Well done Michael for getting as far as you did with accessing the sensor connections, the green sensor is foamed into the rear wall of the fridge and is the evaporator sensor, the red is the fridge air sensor. The white one is the freezer air sensor that clips to the rear wall panel, the black is the freezer evaporator sensor pushed into the bottom of the freezer evaporator coil, there is also a temperature fuse behind the foam insulation at the left which acts purely as a one time blow at around 83c in the event of overheat, all the sensors are as you state 4.7 khOm and should be tested with a thermometer when checking resistance.
Resistance readings are 25c = 4.7k, 20c = 5.9k, 15c = 7.3k and at 0c = 15.3k.
The sensors are all the same with the exception of the fridge evaporator which requires a kit to replace it due to it being foamed in.
Providing the icing was not caused by a blocked freezer drain or the door left slightly ajar or an issue with the heater or blown thermal fuse the the freezer evaporator sensor which you advise was reading 8.6khOm indicates a temperature reading of around 17c and appears OK, this sensor terminates the defrost cycle and then actvates the freezer fan with door closed once the coil has reached between -20 to -25c.
Tony.Hi Michael
Probably not a sensor problem, the sensors are difficult to test on this unit as the connections are in the pcb housing at the rear of the cabinet, bottom left.
Your issue could be as simple as the freezer drain has blocked with ice and restricted the fans airflow and causing the rest of the coil to then over ice.
If the freezer is found to be not getting to temperature, due to over icing the fridge section cooling is shut off untill the freezer regains correct temp, but wont happen untill the freezer coil is completley defrosted along with the drain.
Turn the unit off for several days with the freezer door open, of course without knowing the amount of ice that needs to melt, it could need a longer off period.
Tony.It would appear that nearly every part for this unit is unavailable, looks like its time to buy a new one.
An analogy I use with my customers is a gas leak in the system is like having a slow puncture in your tyre, you either have the puncture repaired or buy a new tyre, so unless the Engineer carries out a leak test ( either by using an electronic leak detector or pressure testing with nitrogen ) and can locate the leak, and if it can be accessed for repair or a part replacement, then yes if it just regassed then it will leak out again, but no time scale can advised without knowing how big the leak is and how long it will last before you are back to square one.
