Blinking Blue Light on B40




April 20, 2013


The blue light was blinking, I added water – it is still blinking and will not brew coffee.  I’ve turned off the machine, waited and turned back on, still blinking to add water and it is full of water.  What should I do?


On a Keurig B40 brewer the blue light refers to the ADD WATER function. And when its flashing it means the machine thinks there is no water in reservoir and so is requesting the user to add some in. Of course what is a common problem, as Sam is experiencing in this case, there is in fact plenty of water in the reservoir but the signal between that and the brewer’s processor is being blocked or breaking down in some way.

So let’s look at a B40’s normal operation and how this situation can arise.When the power switch is pressed a signal is sent to the water pump to get ready and through the movement on water within the internal plumbing water pressure will cause a pressure change to bring water out of the water reservoir and in to the boiler or heater unit (its the large cylinder in side the machine that holds the heating elements). Inside the boiler the water will rise to the point relating to the cup size selected, as measured by a probe inside.

So the break down we have in Sam’s case is most likely to do with a problem with the water sensors, of which two parts we need to check. The first is straight forward enough and that is taking the water reservoir and checking that the magnetic disk on the inside of the reservoir moves up and down freely. As you can see from the photo below the disk needs to be able to travel up and down its enclosure without impediment.

B60 Magnetic Water Sensor

If this disk appears to be working ok the next step is more complex and involves checking on the fixed magnetic sensor inside the machine itself. The photo below shows the senor on our B60, where its attached to the left side wall (looking straight onto the machine). We have removed the two screws the attach it to the side wall just so it stands out a bit more in the photo. This sensor is then connected up into the circuit board of the brewer (which sites on the opposite side of the machine). Being able to check on this sensor and making sure its wires are not broken or the connection has become loose involves removing the Keurig’s outer casing. For more information about this check out our maintenance video section and the two videos we have to help fix this problem. If the sensor does require replacement we have included this component on a Replacement Parts page if you wish to purchase online.

B60 Magnetic Sensor
{ 2 comments… add one }
  • Glenda ,

    I have the Elite Keurig and this is my second one, same problem
    . Trouble first started with the large cup not filling up and coffee coming out very very slow. The Menu light is getting dimmer and dimmer but the selection of cup size light is still very bright and the machine is making a lazy noise like its trying to work with energy (lol) but it dosen’t have any.

    • Hi Glenda and thanks for your question. It sounds like your Elite has some internal pump problems, and perhaps some other electrical issues, for example with the dimming menu light.

      With the pump problems a temporary fix that might help for a little while is the Keurig Burp. It’s more for air pumps, which sounds like this could be one of your Elite’s issues, and readers have found this does work. You can find this guide here.

      However, as this is only temporary, at some point often the next step is to replace the air pump so as to provide a new lease of life. We have a repair guide that takes your through this repair, step-by-step. This link will take you to this guide.

      If you would like to drop us an email using the Contact Us page we can follow-up if you have any more questions or this doesn’t work.


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