Washing machine fills and drains at same time

If a Washing machine fills with water and drains it away at the same time there are a few possible causes. This unexpected behaviour can get the washing machine stuck in a vicious cycle. The water could be siphoning down the drain due to an issue with the plumbing. Or it could be aborting the wash program because it’s detected a fault. Careful observation of where on the cycle the issue occurs will help to work out which of these different faults is causing the problem.

Is Water Draining Out or Being Pumped Away?

Running-waterThe first thing to establish is how the water is leaving the washing machine as it tries to fill up. If the drain pump is definitely not running, but water is being lost down the drain then it must be siphoning. See my in depth explanation of siphoning later in this article.


Water is being pumped away

If you can hear the drain pump running, and the water is being pumped out just as it does at the beginning of the spin cycle, then it could be aborting the wash. Don’t confuse the water pump with a recycling pump (if fitted). They just recirculate water back into the drum.

You should know the difference between the drain pump that pumps away water on rinses and spin, and a recycle pump that runs on the wash cycle. Not all washing machines have a recycle pump.

Could be Overheating

Modern washing machines detect and react to the water being overheated. They can start pumping the hot water away. They may simultaneously take in cold water to cool everything down. If this is what’s happening it should also indicate an error code by flashing lights or lighting up specific option lights or displaying an specific error code via a digital display.


If overheating is the cause of this fault it should happen on the wash cycle. It should also happen after at least half an hour or so when the water has heated up. You should also be able to see that the water inside is very hot. I would also expect this behaviour to be relatively short lived. If the washing machine thinks it has overheated and has aborted the wash cycle, then all it needs to do is cool things down and pump away all of the water. Once this is done it should turn off displaying an error code.

This fault could also be caused by a faulty thermistor (thermostat) giving false readings. If you think you have this fault you’d be better finding an engineer but I have a general help article here – How to test an NTC thermistor.

Other Faults

If the pump runs continuously as soon as the washing machine is turned on and won’t shut off there could be insulation faults on the machine. Call an engineer.


Siphoning Water

If water is just draining away all the time but not being actively pumped out, this is siphoning. The washing machine is trying to fill the drum with water, but water is being lost down the drain. It will keep detecting there isn’t enough water inside and top up with more. Modern washing machines should be sophisticated enough to realise something’s wrong and abort with an error. If not, it may get stuck in this cycle indefinitely.

Siphoning-1Siphoning occurs when the end of the drain hose is lower than the level of the water inside the washing machine. My diagram shows a correctly plumbed in washing machine. The end of the drain hose is higher than the level of water in the drum.


Water always levels. So you can see the water in the drain hose matches that of water in the the drum. If the drain hose was pushed down the waste water pipe much further, or the pipe it pushes into falls over, then water can start to siphon out.

Siphoning can start by the force of gravity, or when water is first pumped out of the machine. The latter happens in the same way as you’d siphon petrol from a car, by sucking the pipe to start the liquid flowing. Remember: if the pump is running it is not siphoning. Also, siphoning is not likely if the drain hose is connected to the u-bend under the sink because it’s so high up.

Has the Washing Machine Been Moved recently?

Siphoning most often occurs when the washing machine has been moved out for cleaning or relocated in a new house etc. It can also occur if a stand pipe isn’t properly secured to the wall and falls over at an angle.

drain hose hookWhen pushed into a stand pipe the drain hose should have a drain hose crook at the end. This not only helps keep the drain hose from falling out but stops it being pushed too far down. The length of drain hose sticking out of the crook should roughly be about 4 or 5 inches.


Full instructions for the exact height of the stand pipe should be available in the instruction manual, or on separate installation instructions that came with the machine.

Overfilling?

If the washing machine overfills it should not simultaneously fill with water. However, if the end of the drain hose is in a standpipe, and low enough, it could trigger siphoning. Water can start to flow out of the drain hose and down the drain caused by the higher level of water in the drum. The washing machine detects the loss of water and keeps filling. This would be rare though. If the siphoning wasn’t triggered, the washer would overfill and flood. If you can see the water levels in the drum are way too high and your washing machine is definitely overfilling try here overfilling.

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30 thoughts on “Washing machine fills and drains at same time”

  1. hi I have new hotpoint washing machine when I start a wash program the washer fills a bit with water then pumps out waits a few seconds then fills again then the wash cycle washes is this normal I have no flashing lights on machine to say theres any problem hope you can help thanks

  2. Hello Diane. Modern washing machines usually fill up with water for a few seconds then stop before taking in the detergent. This is to prevent detergent being washed into the sump hose and wasted. If it fills up and pumps the water out for several seconds it’s probably just trying to flush away old water left in the sump hose after the previous wash. If it washes and spins as you would expect it’s very unlikely there is a fault.

  3. thanks, my washer was siphoning bc the drain hose was so long the end inside the stand pipe was lower than the water level. Problem solved!

  4. Thank you!!!!! I had shoved the drain hose down a bit last week—then was having the fill/drain situation in the rinse cycle. Just changed the hose a bit and I’m up and running! You saved me so much trouble with this advice. Awesome!!!!!!!!!!

  5. Thank you for the article it was very insightful, but I still don’t think that my problem is listed here.

    So I have a 3-year old Samsung washer, and when I press the power button, the drain pump turns on, without even pressing start. It continues to pump constantly, regardless of whether the washing machine is in a cycle or not. So as soon as I start a cycle, the water is drained and never has a chance to fill up. I don’t believe that the computer is recognizing this as an overheating problem, because there aren’t any lights flashing. After working for a little, there is an NF or No Fill error.

    I know that’s a mouthful, but I’m wondering if you can help me out.

  6. Yevgeny, if the pump is running continuously as soon as the washing machine is switched on and won’t stop I’d suspect a possible insulation fault. Low insulation on some parts can cause weird faults but you’d need an engineer who has an insulation test meter to check it out.

  7. Hi Andy
    Ive got a samsung top loader model no WA13UP.Ive been reading your article about siphoning(water running into loader and down the drain) Ive been using my toploader for years in the same position-the drain pipe and suddenly the water just started running down the drain as it pours in?The wash,rinse and spin lights are then on at the same time but the pump is not running-water just keep on pouring in and out through yhe drain pipe. Any suggestions on trouble shooting

  8. Hello Philip. If water is running down the drain as it fills up but the pump isn’t running it can only be siphoning out because the pipe is too low. I appreciate you don’t think anything has changed but there’s no other possible explanation. If the water is being pumped out by the pump though then that’s a fault and most likely caused by the machine detecting a fault and aborting the cycle.

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