Miele Prestige Plus washing machine: 'Check Inlet' light flashing.

[Phil the Fluter]

I've had this washing machine for many years and it has always worked faultlessly.

The only problem I've ever encountered is that, very occasionally, the 'check inlet' light has begun flashing. I have always solved this problem very quickly by checking the inlet pipe for any possible kinks and giving the pipe as smooth a run as possible from the mains to the machine.

Today, however, the 'check inlet' light has begun flashing and despite doing several checks on the machine and its water supply, I cannot solve the problem.

1. I have checked the drain filter and it is clear.
2. I have checked the mains water supply to the inlet pipe and it is normal.
3. I have removed the inlet pipe from the mains supply and checked the inlet pipe filter. It is clear.
4. I have removed the inlet pipe from the back of the machine and checked the filter in the back of the machine at the point where the inlet pipe attaches. It is clear.
5. I have checked the waste pipe running from the back of the machine to the drain outside the house and it is clear.

Despite carrying out all the above checks, whenever I try to start the machine, it starts the cycle as normal and I can see perhaps 500 mL of water running onto the back of the door.

Nothing obvious happens for about a minute and then the 'check inlet' light begins to flash - but, if I wait, I can see the water level continuing to rise behind the door.

The washing cycle never begins.

After several hours testing various things, (normal wash cycle, rinse/drain) and having watched the water level rise higher than I've ever seen it before (about three-quarters the way up the door) I now have TWO lights flashing simultaneously: 'check drain' and "check inlet'.

It seems the machine has no problem taking in water or pumping it out so I have no idea what the problem is

If anybody can offer any advice, I would be most grateful.

[Whitegoodshelp]

Hi. It sounds like a possible pressure system fault. The pressure system is how the washing machine knows when water is inside the drum and when it's drained away. 

The most common fault on the pressure system is a blockage of gunge and slime inside the pressure chamber. 

Check these links

How a washing machine controls water levels

Common pressure system faults on washing machines

How to clear a blocked pressure system

[Phil the Fluter]

Thanks, Andy. I've located the pressure switch and detached the rubber tube and blown into it. It requires some effort to blow into it so, although it is not completely blocked and I am able to blow into it, something is restricting the flow of air.

After doing this experiment and replacing the rubber tube on the switch, I immediately began getting a flashing light on the front of the machine next to "soak/pre-wash'. Google tells me it means there's something wrong with the pressure system.

While doing all this, I also replaced the drain pump and now the machine will drain perfectly – so, obviously, the original drain pump had failed completely.

If I now start to do a normal wash cycle, everything proceeds normally for a very short while and then "check inlet" begins flashing and the machine keeps filling with water until it reaches the bottom of the door. Is that water level normal on an ordinary wash cycle? At that point I always abandon the experiment and drain the water away.

 

[Whitegoodshelp]

Hi. If there is a blockage in the pressure system it's gunge.  Blowing down the small pressure tubing will often only clear the blockage temporarily and even then not properly. Sometimes the blockage will reoccur virtually straight away as soon as water goes in and it all sloshes about. This is because the blockage is like a thick soft sludge. 

The proper fix is to remove and clean the plastic pressure chamber bottle at the other end of the small tube. It may or may not be easily accessible or even detachable depending on design. 

Pressure chamber blockages can cause the pressure switch to jam on, or off. When jammed on the washing machine will not take in water because it thinks it's already full of water and when jammed off it will overfill because it doesn't get the signal that water is inside the drum. 

[Whitegoodshelp]

With the check inlet, just ensure there's no kinked fill hose or tap not turned on properly. 

[Phil the Fluter]

I have now located and removed the pressure chamber, which appears to be immaculate inside and out.

There's no sign of gunge (or anything else) when I look down at the large opening and when I blow into it the air escapes from the narrow end exactly as I'd expect it would if it were completely free from obstruction.

I also filled it with water and blew down the large end and the water squirts out of the little end exactly as I would expect if the chamber were completely free from obstruction.

I then filled it with water and blew down the little end that connects to the rubber tube, and the water shoots out of the large end without a problem.

I have removed the rubber hose from the machine and blown down it. Although it does take a little effort, it's not much more difficult than blowing through a standard drinking straw. I have also squirted water down the tube with a syringe from either end and there's no sign of a blockage.

As for the water inlet problem, the valve coming from the mains pipe is fully open, the filter at that end of the hose is perfectly clean, the hose itself appears completely free from obstruction inside, and the filter where the hose connects to the back of the machine is also perfectly clean. There are no kinks in the hose.

 

 

Edited October 31, 2024 by Phil the Fluter
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