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Good evening all,
Just wondering if anyone has any experience/can shed any light on the above fault?
Essentially, I’ve visited a customer and spent quite a lot of time inspecting, testing and monitoring the above dishwasher.
Initially, the appliance would display the above flashing led’s, and no programmes could be selected (nor lit up/available) along with no change from resetting.
I carried out some visual and electrical tests, including replacing the water flow sensor, and visually inspecting the power board.
Not sure if some kind of hard reset had occurred during the above, as a programme could then be selected… and all seemed fine… drains, fills, washes, heats, rinses perfectly…
However, the above appears to have been misleading… having hoped that the fault/s may have been cured, I switched the dishwasher off, and tried to reset it again to monitor on another cycle/s… yet, the original fault of tap and rinse aid lights flashing, and unable to start any programme recurred.
There is no water in the base, although I have not tested the anti flood micro switch, I suspect the power module.
Having switched the unit off at the plug socket for several minutes, I thought I’d try the machine again… the tap and rinse aid lights immediately flashed as before, prior to then not flashing, and allowing a programme to be set… which I did, and monitored… before the fault recurred…
Looking at some historical posts on here, this seems likely, but I thought I’d ask for any thoughts before quoting for a replacement board.
Thanks,jonty
p.s. I’ve wondered before if the above flow sensor/reed switches can be conclusively tested with a standard multi meter?
jontymox wrote:p.s. I’ve wondered before if the above flow sensor/reed switches can be conclusively tested with a standard multi meter?
the flow sensor is only a reed switch with a revolving magnet in the water flow
if you connect a multi meter on buzz while you start the unit running your meter will pulse buzz buzz as the water flows in
since its only a switch it can never cause any fault on the timer. the only thing it will do is cause a no water fault either if its faulty or there is no water flow for some reason
Dave
Thanks for your input.
I hadn’t considered a heat pump fault; do you feel it may be shorting, and causing such a fault?
jontyjontymox wrote:Thanks for your input.
I hadn’t considered a heat pump fault; do you feel it may be shorting, and causing such a fault?
jontyshort answer dont know
from the bosch manuals i have seen some displays cover a few faults
you could unplug the heater and see if things change as it will run without that
not many manuals about but closest i can find is here. may give you a few ideas
https://www.manualslib.com/manual/958098/Bosch-She4am12u.html?page=38#manual
Dave
I’ve returned to carry out further tests on the above dishwasher, and remain unsure as to the cause of this fault.
Essentially, the tap and rinse aid led’s flash constantly, and will not reset.
The machine will not do anything else now, including trying to set a programme or carry out a test procedure.
I tried disconnecting the heat pump, but no change with the flashing led’s…
Also done some further research, and suspect power module fault.
jontyNew power module arrived today, and will report back on Monday as customer not available until then.
Regards,jonty
Revisited the above dishwasher today, and ascertained that the power module is not the cause of the above… you were quite right, kaibart…
So, as I’m still struggling to diagnose the cause of this fault, I’ve brought the m/c back to my workshop.
Once powered up, the d/w tap and rinse aid led’s flash together, and cannot be reset.
No other function can be accessed… the two mentioned led’s flash in unison, and nothing else… i.e. no drain pump action, filling etc.
I agree that this probably means that the d/w has detected a fault/s, yet simply do not know what!
I realise it’s unlikely, but I wonder if the display board could possibly be faulty/frozen, and if the unit has detected a fault/s, why such information is so difficult to obtain in order to try and diagnose more readily?
jontyWell, I just do not know what else to check/test.
I wish I knew what these two flashing lights related to.
In the manual Dave kindly provided, the above lights flashing in unison relates to a heat pump fault, although it’s for a Bosch dishwasher, and the led’s are arranged differently to the Neff.
As mentioned, I’ve tried disconnecting the heat pump, and electrically tested the heater (fine) with the resulting problem/s remaining.
The tap and rinse aid led’s flash in unison; will not reset, with no other led’s lit…
I’d be grateful for any further assistance!
jontyhave you tried measuring the Ntc’s on the heater. there are 2 of them, both identical, so you can see if they both read the same
Dave
Have you changed the heat pump? As that’s what I would have change 1stas check water and rinse aid means no communication.
this i a easy guide of how these dishwashers function and in this order it will help anyone diagnose a fault on one
1, 3 clicks off relay
2,drain pump runs
3, heat pump runs 3 different speeds
4, fill 1 second
5, pause
6,let’s water in
7, heat pump runs ( if water level not right it let’s more water in)
8, water diverted activities
9,dispenser opens
10, heater comes on
11, if heat exchanger tank fitted on left hand side this fills
If and of these sequences doesnt happen its usually a component. Hope this helps many people as alot of engineers struggle with these dishwashers.
KaiThanks chaps,
Once powered up, the dishwasher will simply revert to the tap, and rinse aid led’s flashing in unison… it will not reset, or allow any other function…
I’ll confirm if the relay clicks tomorrow, as I can’t remember! (there’s certainly no drain pump or heat pump action, nor does it fill etc…)
Thanks again,jonty
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