Regular cleaning of a Bunn coffee maker includes placing the brew basket and carafe in the dishwasher and wiping down the outside of the machine. For deep cleaning, pour a quart of white vinegar into the unit and allow it to dissolve scale from the holding chamber before rinsing thoroughly.
Bunn coffee makers keep a reservoir of water hot inside the machine at all times, allowing for a 3-minute brew cycle. Depending on the mineral content of the water in use, heating the water causes lime buildup in the reservoir. Vinegar is acidic and helps to dissolve the scale. The addition of vinegar to the holding chamber causes the water to flow through the machine. Placing a carafe under the brew basket collects this excess water.
Bunn supplies a long spring with these machines to help remove scale from the water delivery system. To use the spring, remove the spray head from the machine and insert the spring into the tube. Move it back and forth several times to loosen the scale so it rinses out of the tube as the vinegar flows.
After the vinegar has had a chance to dissolve the scale for 2 hours, begin the rinse cycle. Vinegar removal requires pouring 10 or more pots of water through the machine until the vinegar smell dissipates. Once the cycle is complete, replace the brew head; the machine is now ready for use.