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Re: Beko CDA543FW-2 fridge freezer air sensor replacement
Err, we kinda did tell people about it, there’s even an article on it here:
http://www.ukwhitegoods.co.uk/help/fix- … hermistors
That even tells you what thermistors are used.
And, ehm, they’ve been in our store with notes for about a year.
I’d hardly consider that not mentioning it!!!
K.
Re: Beko CDA543FW-2 fridge freezer air sensor replacement
Hi, can you put photos roughly where did you dig right of the pcb box or below it how deep, any info would be appreciated, thanks Robert
Re: Beko CDA543FW-2 fridge freezer air sensor replacement
Just FYI, as the original poster of this thread, I found that the freezer wasn’t keeping the temperature quite as well as I thought a while back and I got sick of messing about with timers. This and concerns expressed here about using a timer on a broken fridge freezer pushed me to get the thing fixed professionally. However, on calling my local engineer, he said it really wasn’t worth the callout, parts and labour (and he’s cheap!) to fix a f/f of that age, mainly because it could entail digging about in the insulation. I trust the guy – he’s been great – so we headed over to Curry’s and bought a new one…not Beko, obviously. All the best – I’ll be unsubscribing now.
Re: Beko CDA543FW-2 fridge freezer air sensor replacement
Hi ElectronicMan, I’m still trying to work out if my thermistor is faulty or not. You say that the impedance was about 11k at ambient temperature – do you know what the impedence should be when the fridge is at 5 deg (freezer at 18 deg)?
Also, which thermistor did you use as the replacement? Thanks.Re: Beko CDA543FW-2 fridge freezer air sensor replacement
Hi ElectronicMan,
Interesting info. I’ve also been frustrated by the wealth of contradictory info on these. Did you use the terminal that plugs into KN3 in conjunction with your new temp sensor? The only sensors I’ve come across for this have bare wires.
Derek
Re: Beko CDA543FW-2 fridge freezer air sensor replacement
Right, apologies for missing some queries and personal messages from ages ago. I will try and answer best I can but I don’t have the appliance here now so will have to go by memory. It still works fine btw.
Earlybird66 – I think I dug to the right of the pcb housing, maybe slightly lower rather than higher, but really not sure. I don’t know to what extent a temperature gradient forms across the rear panel (freezer to fridge) and thus how precise the vertical position has to be. You ask how deep – well very deep – all the way to the metal rear panel – I wrote about the importance of good thermal contact. Just dig out the foam with a scalpel; I don’t see you can do much harm. You don’t need to physically locate and remove the old sensor, and the nearer to the pcb housing the easier it is to route the sensor cable to KN3. Somewhere on this forum someone else has posted photos.
To Bekobeko – sorry I don’t know or can’t remember, but these are NTC types, so resistance will rise as temperature falls. WRT which thermistor did I use, I might be on very dodgy ground here but if I remember rightly there are only two sensors sold for this appliance by Whitegoods. One is a temperature switch (closed or open) and I think helps control auto defrost and the other is an NTC thermistor for temperature control. Again going by memory (and I could be very wrong) the freezer incorporates both parts whilst the fridge employs the same NTC sensor (only) buried in the foam and connecting to KN3. The interesting question is how do the two NTC sensors work together. I suggested a possibility in my previous post. I surmise that the freezer NTC sensor is the master.
To Washdisher – I don’t think I had the correct plug so I cut the wires from the existing sensor (which I never found and hence left in situ) and soldered in the new sensor instead.
To answer your personal message re how sure am I that the appliance will work with KN3 disconnected (i.e. open circuit infinite and impedance as per my last post), well not at all! The sensor is there for a reason and my tongue in cheek observation was based upon a very short period of time so I certainly would not recommend it!If anyone knows how the two sensors operate in conjunction with each other I would be interested to hear.
Finally pleased be warned I am a just competent (I hope) professional analogue engineer and not in any respect trained on appliances.
Hello,
I have EXACTLY the same issue as listed above on a friends Beko CDA543FW 2 unit. I also remain a little confused from the text given above. The fridge freezes everything within it over a period of time. I am not a white goods Engineer, but I am an Electrical Engineer. I am therefore familiar with thermistors ( sensors ), control boards, evaporators, and the principle of operation of the fridge / freezer. I am to understand that this model does not contain an air sensor. The two sensors in the freezer section are the evaporator sensor, and the defrost sensor. The only sensor which controls the temperature is the thermistor buried within the rear of the fridge foam. This is connected to the control unit via the orange / grey wires, and connect to the KN3 termination in the control box. When I test this with an ohm meter, it measured 5.88K ohms. I think that this is acceptable, and therefore working. Nevertheless, I have not yet tested it with a milli volt meter to ascertain if a change in resistance takes place when cooled. That involves digging the rear of the fridge out to gain access to it. Initially, when we gained access to the freezer section, the hole at the bottom of the evaporator was frozen up and blocked. That blockage was removed. The fan runs continuously. I have checked both the resistance of both of the sensors within the fridge section, which BOTH show O/C. Clearly not right. I need to check them using a better meter. ( it was only a cheap friends meter I had access to at the time ). If necessary I need to remove insulation from the wires at the sensor end, to confirm that the wiring between the control board, and the sensor is sound. Having looked on the spares sites, it insists that one of the sensors is a ‘thermal fuse’. I remain unconvinced of this. Please can anyone advise? I am of the opinion at present, that the thermistor and control unit test out OK. However, from what has been said on here, that is clearly not the case. If the sensor buried into the back of the fridge is the only temperature sensor control, it is either that thermistor, or the control board that is faulty. Or both. If anyone can offer any further advice, it would be greatly appreciated. Thanks in advance.
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