Hotpoint BF71 Dishwasher – Humming/Buzzing noise

[alpesh26]

We have a Hotpoint BF71 dishwasher (I believe it is a Bosch in disguise). It’s around 20 years old.

When we start it we can hear a motor noise (like a humming) but nothing actually happens. There is about 1cm of water at the very bottom of the dishwasher and the filters are clean. The timer goes down but nothing is happening apart from the humming/buzzing noise which stops after about 10mins. No errors are shown on the display.

Any ideas what else it could be? Or is it time for a new one?

[iadom]

The first noise you should hear is the drain pump, then it should stop draining and start to fill. I think there is a test routine for these. I may have some tech info buried on my PC or in the cloud. Will have a look and get back to you in a couple of hours.:)

[electrofix]

see if that humming is coming from the inllet valve as 1cm does not sound a lot so am wondering if it filling too slowly although as iadom says the first noise is always a pump but it does not last 10 mins

you could try a long shot and pull the unit out and tilt it back slowly to 45 degrees and see if any water comes out onto the floor. If yes try it again

Dave

[alpesh26]

electrofix wrote:
you could try a long shot and pull the unit out and tilt it back slowly to 45 degrees and see if any water comes out onto the floor. If yes try it again

I did see this mentioned as it could be the flood valve which is stuck and I believe this resets it. The machine hasn’t flooded but as this process costs nothing its worth a try.

It has had this fault before about 1-2 years ago but then it started working again. All we did was take it out and put it back in so it may have put the flood valve in its normal position.

Any suggestions on other things I can check whilst its out would be much appreciated 🙂

[electrofix]

some early bosch machines got gummed up at the left side. you could remove the left hand side and check the inlet path. when it gets gummed up it lifts a float and starts the pump. it can also be a source of a leak that floods the base and triggers overflow float
If it is its just a careful dismantle and clean job

Dave

[alpesh26]

To be a bit clearer on the noise, it sounds like a motor that cannot spin freely so it makes a buzzing noise as there is enough resistance to stop it completely.

I had my extractor fan make a similar noise when the fan casing was too tight around the motor so it fouled the fan blades jamming the motor.

[iadom]

Unfortunately I don’t seem to have electronic copies of that particular manual amongst the hundreds I still have. I would have had hard copies of virtually all Hotpoint appliances so didn’t always need them on my PC. I retired fully five years ago and either dumped or passed them onto an ex Hotpoint colleague who as far as I am aware is still working as an independent. When Dave mentioned a leak you wouldn’t see any water on the floor as the anti flood mechanism should prevent that and just hold the water in the base until you tilt the machine. The fill valves did occasionally stick on these as well. One thing you could try is to start the machine then after say 15 to 20 seconds open the door and fill the tub with a pan or kettle so there is a layer of water covering the whole of the base. About half an inch of water in the base should be enough to trigger the wash motor after you close the door.

[alpesh26]

Thanks for looking! I’ll try adding some water and see if that kicks it in, if it does kick in, what fault does this point to?

If it needs expensive parts I think it will be best to scrap it. Can you recommend any make to replace it with? I was leaning towards Bosch/Siemens/Neff. I like Miele personally but the dishwasher is my parents and doubt they will got for Miele based on cost.

[iadom]

If it doesn’t start to wash after you have filled it manually and just makes a buzzing noise that points to a rare but not unheard of main motor problem. If so it is BER (beyond economic repair). If it drains out correctly after trying it with water in that would confirm the drain pump is OK. I’m a bit out of the loop regarding current dishwasher reliability etc, BSH appliances don’t seem to have the same reputation for quality they once had though. Trade member Don is the man to ask on that front.

[tubafan]

Motor capacitor failed perhaps, as that would make a noise sound from the motor trying to start?

[alpesh26]

iadom wrote:If it doesn’t start to wash after you have filled it manually and just makes a buzzing noise that points to a rare but not unheard of main motor problem. If so it is BER (beyond economic repair). If it drains out correctly after trying it with water in that would confirm the drain pump is OK. I’m a bit out of the loop regarding current dishwasher reliability etc, BSH appliances don’t seem to have the same reputation for quality they once had though. Trade member Don is the man to ask on that front.

I got my dad to try putting more water in and nothing happened. Still got the buzzing noise and nothing drained out.

[iadom]

If you cancel the programme then start again does it drain the water out?

[alpesh26]

I didn’t know how to cancel it, so we changed the wash mode (from full wash to short wash) and still nothing

[iadom]

There is a sequence to cancel and reset, can’t remember exactly what it is now, try holding the start button in for 5 to 10 seconds. Don’t suppose you still have the original user instructions? Basically there are only three things that can buzz/hum. The drain pump, fill valve and main circulation pump. Whenever you start any programme the very first thing that should activate is the drain pump. After a short period of around 15 to 30 seconds the fill valve should allow the water in to fill to correct level then the main circulation pump should start

[alpesh26]

I’ll have to try tomorrow when I go to my Dads. We may have the manual somewhere (I hope as it isn’t available online anymore!)

[Author]

Posts