Siemens dishwasher - drains but not fully

[Ponty]

When you start any programme, does it run the drain pump before trying to fill? This is the normal procedure for every dishwasher I've ever owned or fixed (ex Miele engineer).

Hi, yes, I think it does try to pump out whenever any program is started, but the program soon stops. The pump clearly works as the programs run perfectly fine, but only once any residual water is sponged out (really not very much water).

 

[Bjork67]

This is why I use a cloth and a dish, never failed yet.

 

[david ellwood]

My money is on a clogged drain pump. They normally have a removable impeller to facilitate easy cleaning. It’ll have some spaghetti or some such stuck in it.

 

[Ponty]

My money is on a clogged drain pump. They normally have a removable impeller to facilitate easy cleaning. It’ll have some spaghetti or some such stuck in it.

The impeller has a removable plastic cover. I’ve removed it and checked, it turns freely.

 

[david ellwood]

And it’s keyed successfully to the motor spindle?

 

[Ponty]

And it’s keyed successfully to the motor spindle?

It certainly feels like it is but without taking the machine apart, I cannot say 100%. However, it successfully pumps out all the waste water bar a sponge full.

 

[John Barry]

If you have a wet-vax disconnect the waste pipe from the trap and suck it out. This clears all the water from the machine including the sump and it should then run

This You-Tube tip kept our Bosch going until we could replace it. Our machine otherwise went into fault E24 or E01. Sounds like your have a similar problem to ours where it wouldn't pump all the water out. Siemens & Bosch being essentially the same machine this is a common fault

ps - the new Siemens we now have is a major improvement

 

[TheDecameron]

You've not lived until you've had your mouth around the end of a drain hose, especially if it has been sat in a manky drain for 5 years. Crack on and report back.

My 25 year old Bosch failed to drain for the first time today. Too old to have fault codes. I checked for debris and confirmed the drainage pump was working. I tried blowing down the drainage pipe but was met with resistance. Later tried pushing some cable ties into the sump hole and air bubbles came through. Does the outlet have a one way valve?

 

[matt j]

My 25 year old Bosch failed to drain for the first time today. Too old to have fault codes. I checked for debris and confirmed the drainage pump was working. I tried blowing down the drainage pipe but was met with resistance. Later tried pushing some cable ties into the sump hole and air bubbles came through. Does the outlet have a one way valve?

Not in my experience, that's not to say there isn't one on your Bosch. If you're sure the drain pump is working (how can you tell, can you hear it?) and there is definitely nothing coming out of the hose then my guess would be there is either a blockage in the pump impellor itself or at the pump end of the hose.

You could try some of the methods from earlier in the thread by leaving something in the sump to soak to try and clear it, but most of the time the only way is to get at the pump and take the drain hose off or take the pump off.

 

[TheDecameron]

Not in my experience, that's not to say there isn't one on your Bosch. If you're sure the drain pump is working (how can you tell, can you hear it?) and there is definitely nothing coming out of the hose then my guess would be there is either a blockage in the pump impellor itself or at the pump end of the hose.

You could try some of the methods from earlier in the thread by leaving something in the sump to soak to try and clear it, but most of the time the only way is to get at the pump and take the drain hose off or take the pump off.

I checked the impeller and it’s immediate area for obstructions.
Added some washing up liquid to water in sump, shut door and when I opened it , had lots of foam whipped up on the drain cycle. Could hear a noise too but not the pumping out sound. Whatever happened, it’s working again. I had the machine on its back and couldn’t see an obvious way to get into the case otherwise I’d have taken the hose off for a proper inspection.

 

[gavreid]

I had a bosch machine with this issue. If you take the side panel off there's a narrow and convoluted plastic pipe leading to the drain. Mine had a piece of glass trapped in it which caused a food blockage as the filter had broken a little. Easy fix in the end.

 

[TheDecameron]

After returning to normal functioning my aged Bosch stopped draining again. Impeller working fine but I met complete resistance when I blew back down the outlet hose and I could feel something with my little finger blocking the drain hole at the impeller. I got a track pump and connected it to the end of the drain hose and after a couple of blasts the drain cleared.

I found what was blocking the outlet- this piece of soft rubber-

I was initially at a loss to identify it and noticed , once I had removed the cover over the impeller, a slot in the plastic wall in front of the impeller and directly above the drain hole into which the rubber item fitted perfectly, round part a soft flap that sat over the drain hole. I assume it’s a flap valve.

I’m slightly reluctant to refit it in case it does the same thing again. Is it’s function essential to the normal running of the washer?

 

[Johnjo]

Looks like a non-return valve.

Stops the water in the waste pipe running back into the machine when the drain pump stops I’d guess.

Can you secure it with glue (not the flap part obviously)?