How do I set up my new 10 cup Bunn velocity brewer to brew only 4 cups?

SOURCE: my bunn is too slow

Use the de-liming spring to clean the copper tube behind the spray head. Pour several pots of clear white vinegar through the unit to further remove lime and scale from the interior of your coffee maker. My Bunn is 24 years old, and the only replacement parts I've ever required are new carafes and the 4041 silicone washer repair kit.

SOURCE: bunn initial start up instructions

Here is a link to the manual:

http://bunnomatic.com/pdfs/commercial/manuals/35787.0000.pdf

SOURCE: my 10 cup Bunn coffee maker leaks from the top

I have the same problem and I took the coffee maker apart to find out why. It has to do with a leak on a fitting. On mine I found that the fitting where the hole in the black plastic that the water flows through to get into the stainless steel tank needed to be repaired with some silicone sealant to fix the leak. Still making some coffee!

SOURCE: Coffee grounds overflow out of basket into top of coffee pot.

Coffee overflowing onto the counter is a common complaint found in response to many automatic drip coffee makers. The following are potential solutions that can be used to rule out "operator error" vs. a defect or malfunction:

1. Do not "pack" or otherwise overfill the cone/basket with grinds.
2. Ensure you are using the correct grind for an automatic drip coffee maker, neither too fine nor too course. (See instruction manual.)
3. Do not overfill with water. Use the carafe to pour water into the reservoir. This is because a "cup" in coffee terms is defined as 6 oz, not 8 oz. Note: Some coffee makers define as little as 5 oz as a cup.
4. Make sure the filter cone/basket clicks into place and that the carafe is centered and pushed all the way in.
5. Try a permanent filter rather than a paper filter or vice versa.
6. Only use the correct permanent or paper filter (see manual).
7. Verify that the Pause 'n Serve button isn't sticking. If it is activated too long the brew will escape over the top of the cone/basket. This may be more apt to happen if the alignment of the carafe and the basket is incorrect.
8. Clean your machine with vinegar or as instructed by your user manual at least three times per year, more if your water supply is hard. A properly cleaned machine is less likely to suffer a burned out heating element, to take too long to brew, to produce "off" tasting coffee, or to clog and overrun the filter basket as the water runs through the grinds.
9. Ensure that the coffee machine is sitting level on the counter.

SOURCE: Bunn 10 cup home coffee brewer is leaking from the

These models have a plastic pour-in tray just under the top lid. The plastic on these trays gets brittle over time with the heating and cooling, and they crack where they mount to the tank. The only real way to repair this is to replace the pour-in tray, but these are not sold anywhere that I have found. You might be able to find a used one at a Bunn dealer in your area.
I have seen some people do a temporary repair by putting a washer under the mounting bolt and sealing it with silicone, but this is a temp. fix at best. By the way, the reason that the water appears to be coming from the bottom of the machine is that there is no other place for the water to come out after it leaks from the top.