If your Bosch dishwasher hums but no water flows in, it can have you worried.
For the most part, this means either the dishwasher is not getting water or it’s not draining – some water still sits in the dishwasher after every cycle to prevent the seals from drying and cracking.
So, is there a way you can fix your dishwasher?
Yes, there is. And, it’s fairly easy (as we are about to see).
Bosch dishwasher hums but no water – what causes it and possible solutions
Of course, before proceeding, confirm that the water faucets are fully open.
The water inlet hose might be the issue
A faulty inlet hose will prevent water from flowing into the appliance.
As a result, the water inlet valve will activate and continue humming as tries to let water in.
A faulty inlet hose might be due to three possible reasons:
- It has kinks.
- There are clogs blocking the water flow.
- The hose might be leaking.
How you can troubleshoot and fix the inlet hose
Start by straightening any kinks that might be along the length of the inlet hose.
And, if you note that it’s leaking, you can either patch the worn part or order a durable replacement hose.
Finally, be sure to remove any clogs that might be caught inside the hose.
The water inlet valve might be defective
As a result, it will hum (as it activates) but it won’t allow water into the wash tub.
Fortunately, you can quickly tell if the valve is bad by doing the following:
- Check the valve for calcium deposits (or other deposits) especially if you live in an area with hard water. Of course, if your valve has clogs, you should clean it.
- Confirm that the valve is getting around 110-120v AC when it’s running – a lower voltage might result in the humming sound but won’t be enough to allow for water to flow in.
- Test for continuity between the valve solenoids. If there is no continuity, it likely means the valve is bad and you should replace it – shop for a replacement valve here.
The float assembly might be malfunctioning
The float assembly usually prevents the dishwasher from overfilling by preventing water inflow when the float is activated.
In other words, when the dishwasher receives enough water, the float rises and turns off the water flow (and vice versa).
If there are foreign objects beneath the float, these objects might prevent the float from moving down.
Consequently, this will activate the float switch making your dishwasher “sense” that it’s full of water.
Possible solutions you can try
Inspect for (and remove) any clogs (such as food particles and spoons) that might be underneath the float.
And, if you note that your float cover is coming all the way out of its place, it means it’s not engaging with the switch.
In this case, try to push it in till you hear a click.
Once done, proceed to test the float switch for continuity – you will find the switch behind the kickplate.
If the switch lacks continuity, then you just found what is causing your Bosch dishwasher humming but no water problem.
Fortunately, the part is replaceable (and affordable) – see price at Amazon
The pump seals are dry (or stuck)
Not using the dishwasher for a long time might result in the pump motor seals drying and sticking together.
In turn, this will result in your dishwasher humming but not getting water.
How you can remedy this problem
To fix the pump motor seals, do the following:
- Remove all dishes and any water that might be sitting in there.
- Dissolve three to four ounces of citric acid in one quart of hot tap water.
Pro tip: You can substitute the citric acid with white vinegar though it might not be as effective.
- Pour this solution into the sump area and let it sit for 15 to 30 minutes.
- Run a test cycle to see if this fixes your dishwasher.
The dishwasher might be having drainage problems – it’s not draining
As I had mentioned earlier on, the other possible cause for your Bosch dishwasher hums but no water problem is due to drainage problems.
Here’s the thing: To prevent cracking of the tub seals, a dishwasher leaves some water in the tub after every wash cycle. Once you start the unit, it first drains this water before filling with water for the next cycle.
As such, if the dishwasher is not draining, it might hum (the drain pump running) but not fill with water.
Possible solutions you can try
Start by making sure that the drain hose is clear – straighten any kinks it might have and remove any clogs that might be present.
Something else: If your dishwasher is brand new (or you have recently installed it), make sure that the drain hose has a high-rise loop as shown:
Otherwise, there might be a backflow during drainage which might make the dishwasher not to drain fully.
Finally, remove any foreign objects (clogs) that might have found their way into the drain pump.
Bosch dishwasher hums but no water – parting words
To tell if the problem is due to water drainage or water inflow problems, pour a couple of quarts of water into the machine.
Next, start a cycle and then cancel it to see if your dishwasher will drain.
If it does not drain, it means the problem is due to a drainage fault.
On the other hand, if it drains, it means the problem is likely due to water inflow.