Washing machine doesn't drain

[regsmyth]

Zanussi, about 10 yrs old, but well looked after.
For several years, an occasional wash has failed to complete, requiring manual drain, then the cycle completes.
I found grey gunge coating a float ball thing at the drum outlet, cleaning this seemed to solve the problem.
The float ball rubber unit connects to a long thin pipe going up to the electrics.
But it's getting more frequent now, almost every wash.
I think it has to do with some sort of sensor.

Does anyone know how these things work?

 

[jj4091]

The thin pipe you refer to is going to the pressure switch on top of the drum assy.. The problem you are having could well be that it is blocked or obstructed. I have even seen them get flattened. If you remove the top of the machine you should be able to check the full length of the tube for damage & also remove it from the switch assy & blow down it to clear any obstruction.

 

[regsmyth]

Thanks for the info. I've taken the pressure switch out and the pipe is clear.

There are various clicks of switches when I blow/suck on it, but this doesn't necessarily mean it's working properly.

I'm trying to understand what it is that prompts the machine to drain - is this something in the pressure switch, or will there be a valve or something?

When it fails to drain, it beeps and flashes. I can drain it manually, and while doing that I hear two or three clicks from the pressure switch, after which I can continue the cycle.

Do pressure switches control when the pump will run?
Can they gradually fail?

Or do you think I might be looking in the wrong place?

Many thanks.

 

[JohnD]

have you cleaned the pump filter?

do you hear the pump running?

 

[regsmyth]

Thanks John. The pump filter is the moulded plastic cage that unscrews from the front, revealing the pump blade, but it's all clear.
The pump runs fine after I drain it manually.

What I'm getting at is this: Something must "switch" for the pump to suddenly start running, and evidently, something is preventing this from happening. (Similarly, something must tell the pump when there's no more water to be pumped and hence it stops).

Is there likely to be some other "device" that can enable the pump to run, or prevent it from running? As far as I understand, the pressure switch is mostly to do with stopping the filling process, but is it also responsible for enabling/preventing the pump from running?

 

[JohnD]

I am not a washing machine person, but I would be thinking about putting a meter on the presure switch contacts to verify it is switching.

If the tube is leaky, pressure will escape.

 

[rocks1]

Try it with the ball removed see If it cures it , it could be getting stuck in the sump.

 

[Mikefromlondon]

First thing I would do is to check for any blockages in the pipe and the filter, and see if i could hear any humming from the pump motor, if not, I would check if the pump motor hasn't gone nakkered, try and measure the windings resistance using an ohms meter (multimeter)

 

[regsmyth]

Well if anyone is interested, it turned out to be the pump.
I had assumed that since it sometimes worked and sometimes didn't, that there must be some sort of control that was allowing/preventing it from running.
But I realised it's only on a timer, so I eventually took the pump off for a closer look.
Sometimes the impellor would spin freely, but if I pulled it or pushed it in a bit, it would get stiff to turn - I guess water eventually gets into it, along with dirt/contamination, and hence it had become temperamental.

So there you go, a pump that would randomly choose to run or not run.
Genuine Zanussi spare-around £50, compatible spare-£10. I went for the cheap option. Took about 3 mins to fit. Jobs a good 'un!

 

[Mikefromlondon]

Well if anyone is interested, it turned out to be the pump.
I had assumed that since it sometimes worked and sometimes didn't, that there must be some sort of control that was allowing/preventing it from running.
But I realised it's only on a timer, so I eventually took the pump off for a closer look.
Sometimes the impellor would spin freely, but if I pulled it or pushed it in a bit, it would get stiff to turn - I guess water eventually gets into it, along with dirt/contamination, and hence it had become temperamental.

So there you go, a pump that would randomly choose to run or not run.
Genuine Zanussi spare-around £50, compatible spare-£10. I went for the cheap option. Took about 3 mins to fit. Jobs a good 'un!

Thanks for coming back,your post gives others valuable knowledge as to what else can go wrong, so in thr end the pump motor shaft was just spinning and the fan/turbine was just slipping away from time to time, makes perfect sense, I wonder if some obstruction may have caused this to happen like a penny getting in the way of a fast spinning fan, causing the impeller to stall whilst the shaft may have continued to spin.

 

[regsmyth]

Well not exactly.

The impellor was properly fixed to the shaft, as was the cylindrical magnet.

But there was a sticky black deposit on the side of the sleeve that the magnet fits into, and I think it was this that was sometimes causing the magnet to stick.
The shaft could still be turned by hand, but was too stiff for the motor to overcome.

There was also water inside the sleeve, and I guess it should have been sealed, but the water that got in I guess contained impurities which might have built up.

Or perhaps the rear shaft "cap" had got a little worn, allowing a tiny bit of wobble on the magnet. Hard to be sure, but good to know that this situation can arise.

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[Mikefromlondon]

Oh got you now, thanks for the picture, really helps.