Weak coffee the water appears to go through too fast

You have 3 selections, thus use #1 or #2 for a stronger brew. Naturally the water levels will differ. Get a Reusable Kcup device and pack your own coffee for better results. Get fine ground coffee or grind your own, and then pack the Kcup reusable with your grinds. A fast hot water flow is excellent.

you need to take it to a service center as it is still under warranty they should be able to get it fixed for you

try adding more coffee to the filter, or making the grind FINER or both

Adjust the coffee grinder to finer. (coffee grounds are too coarse)

It sounds like you are missing your sprayhead. If you will call Customer Service at 800-352-2866 with the model we will be able to send you out a new sprayhead.

Basing on personal experience (you can find more on Google probably), solutions are:

On percolated (filter) coffee machines:

Check water temp, if water temp is insufficient , most common is scale heating element , faulty element, faulty thermostat.
Check if water is dripping right at the center of the filter, if it is dripping on one side because the orifice is clogged, that can result in weak coffee.
Coffee blend not well distributed on filter basket.

On Espresso machines:

Check water temp, same as filter coffee machines (thermostat element, scale on heating chamber).
Ensure that coffee is filled correctly in the filter cup (fill at level), and well pressed.
Ensure that the coffee mixture that you are using is not too coarse, buy the apposite one for espresso.
Ensure that you are not leaving the machine brewing for a time that is too long, and Italian coffee cup is very small, approximately one regular shot.

On the hob moka pots (espresso, Moka and Bialetti type):

This are the trickiest ones, you need art and practice to get a good espresso with a Moka, but when you learn, the result is better than what you may get with an home electrical espresso maker.
The frame on the hob must be not too strong, and the mixture coarse but well pressed, with water at level tag, or you will get a weak coffee.
On Mokas a good strategy is keeping hob at minimum, and turning up the flame at top when coffee starts coming out.

French and turkish cafetieres:

Ensure that you put enough coffee, water hot enough, and that you left the infusion enough time to get a strong coffee.

Note: insufficient pressure and clogged lines on electric machines never give you a weak coffee, exactly the opposite.
Not pressed mixture always gives weak coffee, but too much pressed mixture may give you coffee with bad taste.

you probably are not putting enough coffee in to strengthen the coffee

Well, when you set it that low it allows the water to pass very quickly and if the water passes very quickly there may not be sufficient time to absorb the coffee; hence weak coffee. The setting should be reset to the middle, at 10, and tried again. Then, if you want to change it move it only one or two numbers for enough cups to see if there is any change before you move it a large number. Going higher or lower makes it pass more or less quickly with results accordingly.
You may also have the dose set too low and you may want to set it higher increasing the amount of coffee in each dose.
Then again, since it was used, you don't know if the machine was taken apart by someone who reinstalled the machine with the dials you are using out of whack with where they should be set.

George W Conrad.

I don't have a solution but have just experienced the same problem and am baffled. I am using the same beans same grind. In fact using the exact same grind it went from great one day to weak the next day.  I always run it for 15 - 16 secs to get the shot and that hasn't changed. Pressure and temperature appear fine. I cleaned the top of the top filter which was a little dirty but not seriously bad - no change. The coffee flow which is normally chocolate coloured to start with is just mid brown. 

After reviewing troubleshooting diagrams, I really couldn't find a solution to your problem.

The only thing I can suggest is to use 2 oz per pot of coffee grounds. Your 5 or 6 scoops assuming they are one ounce each is way more than enough.

Look under where your basket goes. Most bunn coffee maker has a flavor guard on the downspout. this down spout actually helps distributes the water over the whole basket of coffee grounds. Most of the time I see these missing, and when they are gone, they are gone.

Use less water for the amount of coffee you are using first. Sadly when there is not enough water, the coffee tastes bitter. Too much water tastes weak. Hot water extracts certain elements out of the beans even after grinding.

Always use a fresh paperfilter designed for your coffee maker.
If this pot is not work correctly still, I will suggest seeing your appliance repair technician.