If your coffee maker is leaking or overflowing, try these fixes first.
Is the brewing vessel empty? Make sure that when you’re starting a new brew cycle, the server or decanter under the funnel is empty. Leftover coffee in the server will cause it to overflow.
Check the brew volume. Make sure that the coffee maker’s brew volume is set to the correct level – too high and it could overflow. Your owner’s manual will provide the specific settings and procedures needed to do this. You’ll also probably need to re-calibrate the sprayhead to account for this adjustment.
Clean and delime the machine. A sprayhead plugged with mineral deposits will not allow water to flow correctly – check it for damage, clean, and remove lime buildup as necessary. Also try running a deliming cycle to remove stubborn deposits within the machine.
Test a different filter paper or coffee grind. Your chosen filter paper and/or a very finely ground coffee might create a scenario where water is flowing out of the brew basket slower than it enters it, which will eventually lead to the basket overflowing. Try running a brew cycle with just water (no filter or coffee grinds) to see if it overflows. If it still does, the issue is with the machine. If it doesn’t overflow, try a different filter or a different coffee grind - Bunn recommends using OEM coffee filters to provide the best performance.
When to schedule service: If you’ve tried all of the above steps and your coffee maker is still overflowing or leaking, it’s time to get the technician and schedule repairs. If your coffee maker is leaking from the bottom or anywhere other than the brew basket, it’s also best to give the technician a call, as this could be a simple issue of changing out a seal, or a bigger issue.