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Anyone had a situation where a compressor relay has failed ON and the fridge ends up like a freezer? I’ve replaced thermostat and timer board. The defrost heater and associated parts checked out fine. (NordMende RIFF70302NF)
electrofix wrote: the relay is only a start device
the board and sensors control temperatureDave
Hi Dave,
I have replaced the fridge thermostat (PCB variety, not phial), and replaced the “control board”, and still the fridge section freezes over within a couple of days. The control board looks more like a buck converter and has no ICs that look like working with time functions, but I replaced it anyway. The thermal fuse for the defrost heater element had blown so I replaced that. The heating element and thermostat (defrost) was fine. As it is freezing over rather quickly I doubt it has anything to do with the defrost system. At a loss for what to try next.
Regards, Markkwatt wrote:That is indicative of a sensor (thermistor) failure if it over freezes.
K.
Please see reply above. Thank you.
In simple terms, the board does no timing or anything other than perhaps a defrost cycle where appropriate, it just switches the compressor on, off etc. How and when it does that is determined by the sensors that will vary by model what ones are used and where.
So if the compressor runs continuously about the only explanation there is would be a faulty sensor normally, more so as you have eliminated the possibility of the board by replacing it.
K.
kwatt wrote:So if the compressor runs continuously about the only explanation there is would be a faulty sensor normally, more so as you have eliminated the possibility of the board by replacing it.
K.
Is there another case where the compressor runs continuously because it’s low in refrigerant and is working hard all the time but never getting down to the requested temperature? If so how would it be possible to tell if 1) this is the fault, or 2) it’s a faulty sensor, or 3) it’s a faulty board that switches the relay?
but your first statement said the fridge act like a freezer. the very fact it has the power to freeze everything means there cant be a problem with the compressor as its not only getting to the temperature it should switch off its exceeding it
Dave
electrofix wrote:but your first statement said the fridge act like a freezer. the very fact it has the power to freeze everything means there cant be a problem with the compressor as its not only getting to the temperature it should switch off its exceeding it
Dave
Yes, sorry for the confusion, I went off script for a minute there because I thought I could see a GENERL dilemma for diagnosing problems with thermistor/thermostat which are PCB and not phial type as the PCBs are practically impossible to test and rule out.
I’ve seen that on some Dave, rare but possible.
what happens is the system is trying to chill but if the sensor or stat phial is away from where it’s cold enough to cut out the unit continuously runs. The top of the evaporator chills like mad and it can freeze up but not as cold as a freezer would be but there’s not enough refrigerant or oomph in the pot to get an even temperature across the evaporator. So you get the symptoms described pretty much.
like I say, rare, but entirely possible and not unknown. And for sure not going to be a DIY repair.
K.
yes know what you mean but all the ones i have see you end up with ice bergs stuck to the rear wall because of no defrost phase but since only part of the evaporator freezes they dont seem to get that cold
but then dont get too involved with fridges
Dave
Ordinarily, yes, you’d expect that, but it depends on the unit IME just how it presents and how it’s reported.
But it’s kinda like the phial or sensor being sited incorrectly, the unit just runs and runs, not enough to get a mass of ice but, enough so it drops a few degrees below where it should be and gives the impression of freezing like a freezer to the user but, it’s actually just getting down to or just below freezing point. Enough to freeze especially in lower areas such as the bottle shelf where people see milk etc “frozen” and you get the report of it “freezing everything” when in fact it’s actually doing the opposite in a way.
Unfortunately, I’m not familiar with the specific layout of the cabinet, which can significantly impact the issue. Therefore, I cannot provide a definitive answer in this case.
K.
kwatt wrote:Ordinarily, yes, you’d expect that, but it depends on the unit IME just how it presents and how it’s reported.
But it’s kinda like the phial or sensor being sited incorrectly, the unit just runs and runs…
K.
I wish there were a phial or sensor on this model. There’s nothing except 1) PCB board with the temperature pot on it – and 2) whatever they mean by ‘main board’. I have replaced both of these without any improvement. Is there ever a situation where PCB boards need ‘resetting’ or ‘syncing’ together?
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