Bunn Coffee Maker Not Brewing, Pumping Water or Making A Full Pot

Mike C
Written By Mike C

I've been writing about coffee and espresso machines for 3 years. My goal is to provide you with helpful content that you can trust based on my own personal experiences, information from manufacturers, and tips and tricks I've gathered from other coffee and espresso machine users.

I may get commissions for purchases made through links in this post.

How To Fix A Bunn Coffee Maker That Is Not Brewing, Pumping Water Or Filling The Pot

How To Fix A Bunn Coffee Maker That Is Not Brewing, Pumping Water Or Filling The Pot
Bunn Coffee Maker

Waking up to a broken Bunn coffee maker is definitely a terrible way to start the day. If your Bunn coffee maker is not brewing, pumping water or making a full pot of coffee, don’t lose hope. There are a few things you can try to fix it so you can get your cup of joe ASAP. Keep reading to learn more.

Easy To Fix Reasons Why Your Bunn Coffee Maker Not Brewing, Pumping Water or Making A Full Pot

Is There Enough Water In The Tank?

Your Bunn brewer needs between 20 and 50 fluid ounces of water in order to work correctly, depending on how many cups of coffee you want. Not using enough water could be a reason why your Bunn coffee maker is not working. Make sure you have poured in enough water.

Fl Oz WaterTablespoons Coffee
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Is The Lid Completely Closed?

The lid to the compartment where you pour in water must be completely closed in order for the Bunn coffee maker to work properly. If you don’t close the lid, the water will not go from the reservoir compartment to the internal tank and your Bunn coffee maker will not be working.

Was The Bunn Coffee Maker Left On For A Long Time Without Being Used?

If you left the coffee maker on without using it for a while, it is possible that the water level has gotten too low. Flip the power switch off, unplug the machine, and then follow these steps:

  1. Empty the brew funnel and slide it into the rails.
  2. Fill the carafe with water and pour it into the coffee maker. Do not close the lid just yet.
  3. Put the carafe under the funnel and close the lid. Wait about four minutes.
  4. Repeat steps two and three until water flows from the funnel.
  5. Plug the machine in and flip on the power switch. Wait 15 minutes for water in the tank to heat.

Has the Bunn Coffee Maker Been In Storage?

If your Bunn coffee machine has been in storage, you may need to prime it in order for it to pump water. Flip the power switch off, unplug the machine, and then follow these steps:

  1. Empty the brew funnel and slide it into the rails.
  2. Fill the carafe with water and pour it into the coffee maker. Do not close the lid just yet.
  3. Put the carafe under the funnel and close the lid. Wait about four minutes.
  4. Repeat steps two and three until water flows from the funnel.
  5. Plug the machine in and flip on the power switch. Wait 15 minutes for water in the tank to heat.

Clogged Sprayhead Causing Bunn Coffee Maker To Not Brew Or Pump Water

If you have ruled out any of the above issues as reasons why your Bunn coffee maker is not brewing, pumping water or making a full pot, next you will want to try cleaning the sprayhead. Any blockages there can negatively impact the way your machine works. You’ll need a toothpick, the Bunn deliming tool, a soft cloth and dish soap. Then follow these steps:

  1. Switch the tank to OFF. Unplug the unit from the wall. If it was recently used, let it cool for two hours.
  2. Remove the funnel. Use your fingers to unscrew the sprayhead.
  3. Insert the deliming tool into the sprayhead tube. Leave about 2 inches of the tool out of the tube. Slide the deliming tool in and out of the tube 5 or 6 times. Twist, turn, and use some force when pushing in the tool. This will remove any mineral buildup from inside the tube.
  4. Reinsert the funnel into the machine.
  5. Pour a carafe full of fresh water into the unit, leaving the lid open when done.
  6. Place the empty carafe under the funnel. Close the lid. Water will start to flow.
  7. Take the sprayhead. Use a toothpick to clear any mineral deposits you can see in the holes.
  8. Clean the sprayhead with a soft, damp cloth and gentle dish soap. Rinse thoroughly.
  9. Discard the water from the carafe and place it back under the funnel.
  10. Remove the brew funnel. Screw the sprayhead back in. Return the funnel to the unit.
  11. Plug in the machine and switch the tank power button to the ON position.
  12. After 15 minutes, the water in the water reservoir will have reached brew temperature. Your machine is ready for use.
How To Clean Bunn Sprayhead

Limescale Buildup Inside Bunn Brewer Causing It To Not Brew Enough Or Pump Water

The water used to brew your coffee contains minerals. The level of minerals in your water will be determined by where you live. Some areas have what is known as “hard water” which is higher in mineral content. Over time, these minerals cause limescale buildup inside your Bunn coffee maker. While not toxic, this can impact the coffee’s taste and temperature. It can also negatively impact your Bunn coffee maker perforamance, causing it to not brew, make a full pot or pump water at all. Descaling, also known as deliming, is the name of the deep cleaning process that removes these minerals.

In addition to difficultly pumping water or less than expected coffee volume brewed, a slow dripping instead of a full flow is another sign that you need to descale. You’ll also want to descale your Bunn coffee maker if you’ve left it unused for an extended period of time and did not empty the water from the internal tank. Limescale likely built up during this time.

You will need to find the Bunn deliming tool that came with your machine or order a replacement in order to complete this. You will also need to decide if you want to use vinegar or a commercial descaling solution.

Can You Descale A Bunn Coffee Maker With Vinegar?

If you look in your user manual, you will see that Bunn’s descaling instructions use vinegar. If you have some around and you are comfortable with that, go for it. Other manufacturers will advise against using vinegar. White vinegar contains 5-8% acetic acid and apple cider vinegar has 5-6%. This type of acid can wear down metal and cause leaks. Vinegar is also less effective than other cleaners at removing oils left by used coffee beans. Plus, it may leave a lingering taste or odor which may make your drink unpleasant.

Instead, I think the best way to clean your Bunn is with one of the below cleaners. They have safe and effective types of acids and they are odorless too and won’t impact the taste of your coffee.

Bunn Coffee Maker Descaling Solutions

Impresa Descaler

Impresa Descaler - how to clean a bunn coffee maker

The Impresa descaler is a top selling cleaner. It has citric and sulfamic acids. Both of these are gentle on metal. Each pack contains two bottles. Each bottle can be used twice.

Essential Values Descaler & Cleaner

Essential Values Descaler - how to clean a bunn coffee maker

The Essential Values cleaning solution has a citric acid that is both odorless and powerful. Each bottle is good for two uses. A two pack will provide four doses. That’s a year supply if you clean your machine every three months. 

How To Descale Bunn Coffee Makers

Once you have your descaling solution and the Bunn deliming tool, follow these simple steps on how to clean a bunn coffee maker to get rid of limescale buildup.

  1. Slide the brew funnel into the funnel rails. Place the carafe under.
  2. Open the water fill lid, and then:
    • If you are using vinegar, add 32 fl oz of undiluted white vinegar into the top of the machine
    • If you are using a descaling solution, follow the instructions on the packaging to prepare the solution-water mixture in a container. Then pour it into the top of the machine
  3. Close the lid. Flip the side tank switch on. Allow the vinegar or solution to stay in the reservoir for at least two hours. During this time it will mix and heat with the water.
  4. After two hours, flip the switch on the tank to the OFF position. Unplug the unit. Let it sit for at 30 minutes to cool down.
  5. Remove the brew funnel. Unscrew the sprayhead.
  6. Insert all but one and a quarter inches of the deliming tool into the sprayhead tube. Pull the tube back and forth five times. This will help dislodge any buildup.
  7. Replace the sprayhead and then the brew funnel.
  8. Now you need to rinse out the vinegar or solution. To do this, fill the carafe with fresh water only, pour it into the machine and brew. Place the carafe under the funnel.
  9. When done, discard the contents of the carafe. Rinse it thoroughly.
  10. Repeat step 8 three more times. If you used vinegar, you may need to repeat this more than three times to get rid of any lingering odor.

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