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Re: NEFF G4344X6GB/04 freezer – intermittent alarm sounding
Thanks BenLucySam for your thoughts. I hadn’t considered the possibility of frost actually propping the suction valve open, maybe that was the problem. At any event, the compressor never seemed to achieve much cylinder pressure during the fault condition or else the outlet pipe would have remained hot.
Sequel:
Over a few more days of running, we found that the thermostat had to be gradually lowered to prevent the fault recurring. I did think about drying and re-gassing, but decided not to throw good money after bad and simply bought a replacement model, the G4344X-7-GB for about £350 back in January. This freezer seems identical except that the original Embraco EMZ40CLC compressor has been replaced with an ACC HXK70AA unit and happens to be much quieter as a bonus.Just for fun I burnt off the iso-propane “lighter fuel”, which was nowhere near as exciting as I’d hoped, 😉 but couldn’t then be bothered to hacksaw the can apart, and split the compressor
for a post-mortem so we’ll never know whether it was a failing inlet reed valve, I’m afraid, although I can’t see why the alternative theory of a water contaminant issue should arise after 4 years of service!But then then the washing machine element began to trip the RCD… Life goes on… :rolls:
Re: Neff S51M53X0GB/16 intermittent no heat but no E codes
SOLVED IT!
I found that one of the HF3FD relays switching the heater elements had a contact resistance around 75 mOhms and significantly higher than the other one but decided to replace them both for safety. Problem solved. The dishwasher’s now put in at least 5 successful washes without any of the coma-like stops, cold dry-cycles etc., and the wife’s more than happy that I’ve finally removed my data-logger and cables from the kitchen 😉
Couldn’t find any HF3FD (HF3FD -012-ZTF) easily available on sale in the UK so I replaced them with two OMRON relays type G5LA-1 12DC which according to the data sheet were practically exact replacements (IMO type SRM-1C-SL-12VDC should be another alternative if anyone’s interested).
Out of interest, I hacked the top off the more suspicious of the two original HF3FD relays and sure enough, there was plenty of evidence of splashy arcing and burning of
the contacts with a small amount of sooty blackening inside the case lid.Having been right through the circuit of the control board looking for potential faults, (and finding nothing wrong with those suspicious capacitors!) I then turned to the relays used to switch the heating element(s). The designer clearly had safety in mind here, using dual heating elements in the “heat pump”, a separate relay in each of live and neutral, and (judging only from the copper tracks on the circuit board), apparently providing the ability for the micro controller to monitor the heater ‘centre tap’ voltage.
I feel happier to leave the dishwasher unattended knowing that this control board probably has the ability to identify and safely disconnect should one of the relay contacts begin to begin to arc and spark or even weld closed under fault conditions. It’s possible that this is monitored by the microprocessor looking at noise on the midpoint voltage for example… And by the way, it was interesting to note that there are two identical NTC thermistors built into the heat pump, presumably for redundant comparison checks – good stuff; they really don’t want this thing to accidently boil up either!
I also found (though playing) that the ‘P00’ status of the display enables you to cycle round (using the flashing cold rinse button) and view the last 8 error codes reported, one each at the end of a wash, and it seems that E00 means that the entire wash was successful. It turned out that this dishwasher was leaving a trail of E02 errors which of course eventually happened continuously… The reason I reported no E codes in the original thread title is because none show on the display after the wash. This dishwasher is intended for fitment under a worktop, the display is blanked during the wash even if you could see it with the door closed!
So I hope this helps anyone with an out of warranty Bosch/Neff/Siemens dishwasher with an EPG 60110 TyP PA control module, who feels confident with safely handling electrics/electronics and with the necessary skills and understanding to cleanly change components on circuit boards; the relays are as cheap as chips, the modules are not!!
For the curious, there are five HF3FD relays on this module; one bridges the 100 ohm surge limit resistor (after the initial power-on checks are done) to provide the DC 375v (-ish) rail, two are used to switch two of the three phases from the FSB50250AT motor driver chip (under the heatsink) between the circulating pump and drain pump motors, and the final two simply switch Live and Neutral to the heating element(s). If you can’t confidently identify these two, you probably shouldn’t be doing this repair; please don’t blame me for your house fire!! 😀
Re: Neff S51M53X0GB/16 intermittent no heat but no E codes
Hi Martin, thanks for coming back. Well, I was rambling aloud really. I’d forgotten that there were 5 x mains rated relays on the board, two for the heater, leaving 3 for the main pump and so on I guess, but the relay primaries are 12v so that part of the guess and the smoothing cap theory is worth my checking – nothing to lose given the cost of a new control board!
But I’m still puzzled by those “engineering” codes I stumbled on, (p00 thru p07 on the display) and am still hoping someone offers a clue.
Anyone?
Re: Neff S51M53X0GB/16 intermittent no heat but no E codes
Hi Martin, thanks for coming back to me.
I have to admit this is what I’d been wondering, but I have a couple of questions if I may before rushing to purchase a new one.
Firstly, is there anything I can usefully access from the “hold two buttons down and power up” menu, i.e. P00 – P07 which might help me reset the logic, or confirm whether it’s still even configured for the machine it’s in, and…
Secondly, have you ever seen problems typical of low ESR electrolytic caps drying out and going low value (or just becoming high ESR!) on these control boards?
A brief visual of the control board finds only one large smoothing cap on the output side of the SMPS with a DC voltage rating of 16v. If I were a gambling man I’d say that all the small low power motors, pumps, solenoids etc. were going to be 12v rated and probably therefore the logic with it. (Easier to get through the Low Voltage Directive wasn’t it!)
Now if that cap suffered the same fate as many aluminium foil electrolytics do, then the logic may be struggling with an unsmoothed, spiky supply… Ever seen this happen on these dishwashers, or am I in uncharted waters here? In any event I shall end up putting a ‘scope on the rail but maybe you’ve already been here?
Best wishes, and TIA!
Re: Neff S51M53X0GB/16 intermittent no heat but no E codes
Hi again Martin,
The plot thickens…
I set ‘d01’ as you suggested and ran the dishwasher today with a chart recorder monitoring the input AC current to help identify what the machine was doing at any time without me camping next to it for hours.The m/c appears to have begun the selected ‘auto’ 45C-65C (2hrs 40mins) with it’s recent trick of a hot pre-rinse followed by cold wash and then a useless cold drying session. But not content with that, it seems to have immediately started a complete new cycle of hot wash (with no pre-wash), a cold rinse, then a hot drying cycle which it completed by 3hrs and 50mins, but then then wanted to repeat it ad nauseam!
I eventually managed to break this endless cycle but it wasn’t easy.I’ll be as brief as I can with the details, but inevitably it will be a bit of an essay, apologies.
I selected the ‘auto’ 45C-65C setting with a full load of dirty crockery, the flashing display indicated 2hrs 40mins instead of the usual 2hrs 30mins as expected with the extra hot drying selected. Pressed start, shut the door.
At 2.5 mins, the first water had filled and heating began for the next 11 mins. Immediately after the heating stopped, the machine fully drained at 18mins after the start. It then cold filled again at 20 mins and the detergent compartment sprang open at 21 mins.
The m/c then proceeded to slosh around with typical washing noises but never heated this water. At 1hr 9mins into the program, this (cold) wash water pumped out.
The next cold fill completed at 1hr 12mins followed by low intensity sloshing ’til 1hr 24mins, then it sat quiet for 2.5 mins, then burbled and pumped out ’til 1hr 33mins after which it sat doing nothing (i.e. AC current less than 15mA) until 2hrs 7mins.
I can’t tell you whether the red “busy” LED was on or off during this time, ‘cos no-one was in the house at the time, but the mystery now begins.
At 2hrs 8mins it pumped in fresh water and heated this until 2hrs 17 mins after which it continued to slosh the hot water around (but with a different sloshing sequence to the earlier washing phase). This cycle continued until 2hrs 45mins whereupon it pumped this hot water out and cold filled again. It sloshed this around cold until 2hrs 54mins when it drained, and refilled by 2hr 56mins.
At 2hrs 57mins it began heating which continued ’til 3hrs 16mins after which it immediately drained the water and sat doing nothing ’til 3hrs 50mins
Here the fun began…
The red “busy” light went out at 3hrs 50mins accompanied by the usual beeping, but before the door could even be opened, the red light came back on and the m/c began cold filling AGAIN!
Freaky – it’s never done this before – I whisked the door open, still hot and steamy as expected but now sprayed with the incoming cold. With the door open, the (flashing) programme display showed 2hrs 38 mins remaining of a now interrupted new wash cycle! I then powered off and rescued the (hot, clean, wet) contents of the machine.
Powered back on, held the START button down to reset the timer/counter to a flashing 0:01 then shut the door expecting the normal pump out, red LED off, and beep cycle.
Sure enough, it did all that, but after a few seconds of beeping, the red LED “busy” light came back on and ANOTHER wash cycle started itself!!!
Did the same again, 3 second press to reset counter to 0:01, shut door. Same loop again, pumped out, led out, beep, led back on, new wash cycle started…
I tried several times more to interrupt this process without success. Every time the door was whisked open on the split second of completion, the new cycle was already locked in and could not be changed with any programme select buttons.
Even powering up with any two buttons pressed and held failed to break out of this loop. By now, panic was setting in and I’m afraid a frenzy of experiment began with various combinations of ‘power on with START button held down’ etc. whilst opening and closing the door at different points in the loop until FINALLY due to some combination I failed to remember for next time (dammit!!), the m/c finally broke out of this infinite loop and came back to a normal state whereupon the next programme could be selected, run, cancelled and pumped out to a normal completion every time.I have not run the machine since to see what happens next but somehow I’m not expecting a normal performance 🙁
With apologies again for the length of this essay…
Have you or anyone seen anything like this behaviour, or have a clue what caused the endless cycling above?
… and of course, what’s next to examine for the actual fault! I have one more check to make on the control board and beyond that, I’m out of ideas – please help!Re: Neff S51M53X0GB/16 intermittent no heat but no E codes
Hi Martin, thanks for the reply…
No, I hadn’t tried altering this from the default setting “d00” ‘cos it made no logical sense to me. *When* the m/c decides to properly heat the final rinse, it takes around 2.2kW for 19 mins, which by my calcs is about right for 55C *rise* in water temp (cold feed presumed around 10-15C), so it *can* do it when it *wants* to do it!
Any further thoughts?
However, for completeness, I have now set “d01”, the optional ‘Intensive Drying’ value and I’ll see what happens to SWMBO’s plastic ware if it springs into life on the next cycle 😉
