Why Does My Bunn Coffee Maker Leak?

Table of Contents

Why does my Bunn coffee maker leak? There can several reasons that can cause the malfunction in the Bunn coffee maker. The below write-up may help you to find the reason behind the leak and solve it.

Bunn coffee makers are one of the widely used coffee makers in the USA. Due to the efficient and reliable performance of the appliance, it is vastly used in both home and commercial spaces. Typically, Bunn Coffee makers are very well-designed and they are built to last long. However, just like any other appliance, this coffee maker can also malfunction.

In today’s guide, we will try to find out the malfunctions that can cause the leak in Bunn Coffee Maker. Keep following the article to find out the reason.

Things That Make Bunn Coffee Maker Leak

A coffee maker can leak water from the reservoir or from the internal pipes while brewing the coffee. There can be some other issues too. Below, we will try to illustrate some of the main causes behind the leak in a Bunn Coffee maker:

Damaged Silicone Seal

Some models of the Bunn Coffee Maker include silicone seals to separate the water tank and water reservoir. Typically, the BUN NHBX model and the other that includes double water reservoirs usually show the issue. The machine uses soft silicone seals. It can get damaged due to consistent use. Moreover, the heat of the machine can melt the silicone seal. If the heat gets damages, your coffee maker will start leaking.

Unfortunately, it can be a bit tough to solve the issue. Besides, you will not get it repaired by the company as this issue is not covered by warranty.

Mineral Deposit Buildups

Another reason that can cause the leaking is the mineral buildup inside the machine. The water you use for making the coffee includes minerals. The minerals can accumulate buildup in the internal parts of the coffee maker which can lead to clogs. And, when the clogs happen, the machine will start leaking.

It is important to clean the buildup once in a while. Apart from malfunctioning the machine, it can also affect the taste of coffee. The water in the machine will not be heated properly which will lead to weak coffees. The deposits can cause some other issues and they can eventually affect the lifespan of the machine.

Fortunately, cleaning the buildup is not that hard. All you need to do is to give a thorough clean using the vinegar-water solution, lemon, baking soda, or the commercially available solutions by the coffee maker manufacturer. Check the user manual of the coffee machine where you will find the steps to follow for removing the deposits.

Brew Volume and Empty Vessel

While making the coffee in the Bun Coffee maker, make sure that you have set the brew volume at the right level. Setting the machine’s brew volume can make it overflow. You should find enough information on how to set the brew volume correctly. Refer to the guidebook to solve this issue.

Sometimes the overflow or leak may happen by the empty brewing vessel. While starting a new brew cycle, make sure that the decanter, also known as the server is empty. If there is leftover coffee inside, this may cause overflow when you run the new cycle.

Internal Damages

The Bunn coffee maker is pretty strong which might make you think that handling the machine roughly will not be an issue. But that’s not true. Handling the machine in the wrong way can cause occasional damages and tear inside the machine. Such as, it can damage the internal circuit connection of the machine. Sometimes, it can also malfunction the tubes that transfer the water and coffee.

How to Fix a Damaged Silicone Seal

If your Bun coffee maker is leaking water due to a damaged silicone seal, you might give it a try to solve it. Note that the steps are going to be a bit tricky. So, don’t try it if you are not confident. You will require replacing the seal. Here is what you will need: Silicone Sealant, Silicone Gasket Replacement Unit, and a magnetic screwdriver. Here are the steps you will require following:

  1. Open the top cover of the machine by loosening the screw by using a compatible screwdriver.
  2. After that, remove take out the plastic plunger. This is the part of the machine that controls water flow.
  3. Now you will see the silicone seal after removing the plunger. It might be melted or broken which is causing the water leak.
  4. Take off the old silicone gasket and replace the new one in its place. Use the commercial silicone sealant to make the gasket sealed and waterproof.
  5. Leave it in this situation for a few minutes. This will make the bond stronger.
  6. Afterward, you can pour water inside the machine and check whether there is a leak or not.

There shouldn’t be a leak if you have implemented the steps carefully. If only the seal is damaged and the gasket is okay, you might not require replacing it. Instead, use an adhesive silicone sealant to repair the seal.

How to Remove Mineral Deposits from the Coffee Maker

If your machine is leaking due to the mineral deposit buildup, you should follow the steps to solve it.

  1. Empty the carafe and water reservoir. Now fill the water reservoir with one part of vinegar and one part of water.
  2. Afterward, turn on a brew cycle. Let the brew cycle complete following the usual way. When the vinegar-water solution goes inside, it should clean off the deposits.
  3. You might repeat the process if the clog is not removed yet. After that, discard the residue of the cleaning solution from the carafe.
  4. Now fill the machine with clean water and run a new cycle. This should remove the smell and flavor of vinegar from the coffee maker.


If your Bunn coffee maker is leaking, the above information should help you to diagnose and solve the leakage. If nothing works, you can contact the customer service of Bunn. They can help you to repair the leakage.