Siemens SN66T096GB/52 No Heat and No Spray

[Clusterm2]

Help…
My dishwasher fills, times through the selected cycle and drains, but the water is cold and there’s no spray water (possibly some flow but at very low pressure). This model I discovered has a heat pump so my presumption was that this pump had failed, however I removed the pump, the impeller is free to turn and the meter readings all seem to be fine, motor balanced@ 54 ohms, heater circuit 20 ohms and thermistor 12k ohms 1-2 and 24 kohms 1-3.
So what makes the heater / motor cut in and in what order? Am I looking in the wrong place entirely?

Edited to add
There are no fault codes showing

[andyjawa]

Did you measure the heater to the earth tag one of the 3 spade tags on the motor heater block. There is nothing special about that siemens model it is just a cosmetically glam`ed up Bosch. The motor and heater is contolled by the pcboard bottom r/h/side corner – not saying that pcb never goes wrong but it is unlikely based on my experience but have the part number anyway 00655712 preprogrammed for your specific model at a “mere” £222.16 so you do not want to guess and it guess wrong. The heatpumps are famed for failure, the achillies heel of the whole series of Bosch/Neff/Siemens, part number for your model is 00651956 £139.73 ( crickey they`ve gone up!) so you want to double check there especially as they are famed for the heaters going to earth without taking trips out. There are about 4 ways heaters fail not just the usual obvious way of just open circuit or just a ohms reading between its L and N. Set you test meter with a very good battery on highest ohms possible and with luck you will be able to prove it is to earth, the trade uses a 500v dc mega to test these things – any reading using an ordinary multimeter showing it is to earth is your answer and if that is the case it would be no surprise to me..

[Clusterm2]

Thanks for the quick reply. I had megger tested the heater cct, clear @ 500v ( I was an industrial electrician). My problem is not knowing whether the heater cuts in first, before the motor or does the water need to get up to temp before the motor runs or is there another sensor that’s not being satisfied etc, or….however clear the motor readings are, it could still be faulty, impeller spinning on shaft before it gets up to speed for example…I just don’t know if the control panel is asking for the heater / motor, is it worth removing the control panel? Is there a relay in there that may not be closing or are the relays solid state?
Would an experienced repairer just try replacing the heat pump?

[andyjawa]

On the quick wash programme for example (i.e. so no confusing prewash) it would be : outlet pump on then water fills as motor on, motor on washing noise good and proper as water has now stopped filling by being sensed, I think, by the sensor attached to sump part 00611323 working electonically inconjuction with the reed fill sensor attached to the l/h/side water fill chamber, soap dispenser opens, then it heats.
“it could still be faulty, impellor spinning on shaft before it gets up to speed for example” possible but never had that happen myself but then you could be spot on. The pump part of the heatpump often just do not work = they may read through ok, the impellor turns ok by fingers/thin screwdriver but the damn thing is still faulty and that is the really annoying factor in all of this.
Thought the control (main pcb) at the bottom r/h/side corner is more likely than the user board (as the part itself) in the fasia panel to be at fault but I have to say that I never changed the user fascia pcb and only ever changed 1 main pcb because it had blown up. BUT possible that the user board loom could have a damaged wire behind the door panel at the bottom, not generally common because there are few wires but possible, had that only once myself on a Bosch /Siemens but it wasn`t the fault you have but was, from memory, a very similar model to yours.
“Would an experienced repairer just try replacing the heat pump?” Well it would be his/her first point of call I`d imagine. Your problem is though most repairers have cottoned on that the heatpumps are a load of trouble and can fail at the drop of a hat and so many will not be keen especially since they would have to warranty the part. This was, it should be said, why I stopped all dishwasher work no matter the make in 2018 to focus purely on washing machines and preferably old ones, in other words I got my fingers burnt on Bosch d/washer heatpump failures- they cost me roughly 600 quid out of trade warranty or what laughably passes for one, heater failures every one. Your trouble could be the sensor 00611323 £18.60 from Siemens / bosch that is one of the least expensive part the other is the l/h/side fill chamber reed swt fill sensor 00611317 £19.43 (if that one fails by itself you usually do not get any fill but you do get a fault code) try unless someone else on this site says I`m talking kriptonite – and that could well be!! No official published info other than parts, no wiring diagrams, sod all available unless you work directly for bosch/siemens.

[andyjawa]

On the quick wash programme for example (i.e. so no confusing prewash as far as I know) see your instruction book
This is the quick wash as on your machine but called:
Express Wash/
Speed Perfect/ (VarioSpeed) *
This function can reduce the running
time by approx. 20{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} to 50{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} depending
on the selected rinse programme. The
change in the running time is indicated
on the digital display. To obtain
optimum cleaning results at a reduced
running time, water and energy
consumption are increased.

I know you say the machine fills but if the sensor/s are u/s you can get them to still fill just that the machine is not told to trigger the heatpump to start washing. Those, other than the heatpump itself, other parts I listed may or may not cure your problem you you take pot luck there. To be honest unless your there it is difficult to suss the machine out. I know that rattling on about the heater failure (which is very true) but then equally I have the actual pump part of the heatpump just die too (not as often as the heater but still classed as fairly often) but if you are getting water and no heatpump action, as you say, then it may point to the heatpump itself, could be the main pcb, but the intitial part you could try is the sensor 00611323 £18.60 trouble is all the other parts are not 5 bob and so serious money and any one of those might not be the problem causing major grief. Have you had a look at the main pcb at the bottom? Just because I only ever changed one does not mean you pcb is not the culprit other people might have changed many for all I know- you would have to remove the r/h/side cover the mains lead connects into it directly into the pcb via a plug affair just take a photo/s where the wires plug into the pcb when you`ve got the pcb out: can be a bit of a battle it is a case of disconnect plug and the pcb you push upwards at the same time using a flat bladed screwdriver about 4″ to the left to gently ease the plastc casing off its side locating lug as you gently move the pcb upwards; from memory it is easier to first remove the pcb top cover shield plate.
My gut feeling from this end is that it is more likely the heatpump is duff but it is your gamble.

[Clusterm2]

Thanks for your help. I’m away at the moment but decided that I’ll have a look at the main pub, if nothing obvious I’ll replace the pump and the sensor you mentioned…I’ve sort of decided that the satisfaction I’ll gain from it being repaired for £150…outweighs the sadness having to pay out £800 for a new one (it’s integrated) will cause….and I’ll still have a couple of spare pump / heaters I suppose….if they’ll fit..
Thanks again

[andyjawa]

Best of luck.

[Clusterm2]

Updated to add, a new heat pump unit sorted it. Somehow I’d failed to see that the outer vanes ( but still in one piece ie a ring of blades) on the impeller had parted company with the inner part….obvious when the new part arrived. So thanks for the help.

[andyjawa]

make sure you keep all your receipts. These wretched heatpumps are a curse to mankind and so apt to fail again fairly soon appears, least to me, no rhyme or reason that they do just that but they can do.

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