Mend > Washing Machines

Mend Bosch WFL1200 Washing Machine Blocked Pump

How do I eliminate vacuum forming in a BOSCH Maxx WFL1200 drain system?

Hi,

For the past couple of weeks, we’ve been battling with our washing machine’s draining / spinning cycles (Irrespective of the program and/or temperature it’s on). As soon as the program reaches the draining / spinning cycle, the machine stops and the control light flashes. AS PER THE USER MANUAL, the concerns seems to be a blocked drain hose caused by fluff producing items which were washed on a high temperature.

I have checked all hoses and cleaned everything I could as per the user manual. I have also removed the drain pump and verified that there’s nothing obstructing the water to flow towards the impeller. As soon as I fit the pump again (and the plastic ball inside moves freely), the machine washes successfully for approximately 3-5 washes until the concern repeats itself. What I have determined though, is that the plastic ball inside the drain “pump” is stuck in an upwards position EACH time this occurs. It’s as if the draining system from the drum to the pump forms a vacuum and sucks the plastic ball towards the drum which fills the tube and triggers the sensor to indicate “a blocked drain pipe”.

In order for the water to flow without obstruction, the plastic ball should be in a downwards position to allow the water to flow towards the impeller. I have also verified and determined that the system from the impeller onwards, operates well (tested by inserting water through the hose exit in reverse and then spinning it)..

Any suggestions will be HIGHLY appreciated.

Many thanks in advance!

Benjamin van der Merwe
June 2015

Bosch Bosch WFL1200 Household Appliances, Washing Machines Washing Machine Blocked Pump

Many thanks to all, your input is much appreciated!

Seems like incorrect terminology from my side. The plastic ball is in the hose, not the "drain pump". It means that this area seems to function normally if I consider your explanations.

Kenjo, the impeller / bearing is basically the only possible cause I have not yet investigated. I'll check it out.

Many thanks all.
Benjamin.

Benjamin
June 2015

if the machine is plumbed properly,there will b no back flush,but plumbers are lazy at times and connect the drain to the u bend
instead of a stand pipe 2.5 inches in diameter and two feet from the ground,the manufactures give plumbing instructions,but the bright boys ignore them,and go for the easy option

gts
June 2015

take ball out,toss it away,simple

gts
June 2015

The ball in the hose is designed to rise to seal the drum when the pump stops due to the backflush of the water in the raised drain hose, not a vacuum. Unlikely to fail, but check the impellor in the pump to see if there is sideways play in the front bearing, this can allow the rotor to pull to one side and jam in the permanent magnet stator, it will be intermittent at first before becoming permanent, then the water does not drain so the ball is raised by design. Cheers

Kenjo
June 2015

There shouldn't be a plastic ball inside the drain pump. There is a plastic ball inside the hose which comes from the tub down to the pump. It goes at the top of the hose next to the opening from the drum. Gravity allows the water to fall down the hose to the pump. The spinning impeller forces the water through the pump and up the drain hose.

Lincoln Appliance NZ
June 2015