I have a STF-35 , brews more then the pot , can you adjust the amount of water per brew ?

This could be an issue with the wiring of the fill and brew valves or it could be an issue with the control board. When you draw water off, the machine should replace the same volume of water by opening the fill valve. If the brew valve is opening at the same time, tgen there is an issue. I recommend placing a service call.

You should call your vendor for service on any commercial brewer. (Especially if it's on loan from them)
*** the following is for information only as all repairs should be performed by a qualified tech.***

Most commercial (plumb in water line) has a start switch activates the timer (analog or digital) board which turns on the water feed to the brew tank. This forces previously heated water out and sprayed over the ground coffee in the brew funnel. Coffee then drips into the decanter. Under filling is caused by un-calibrated timer or interment timing.
* The timer comes in two types; Dial (old) and Digital. If it's the dial then a simple turn of the dial will make less or more water flow to decanter. You MUST re-brew (no coffee, but use funnel) into the decanter or pot that you plan to use. Don't mix up different size pots as the timer is only good for 1 setting. Turn dial and brew once to check. Keep checking with a brew after each adjustment. Do a final brew just to be sure.
* The digital timer is a bit more complicated to adjust. Sorry, too many switches and options to go into it here. Check your MFR online for a manual (usually a FREE download). Several methods may be listed.
* If it does not adjust or won't keep the set time then. Replace the timer. Digital timers tend to be sensitive to electrical storms. Analog timers have a dial and are more tolerant of electrical surges.
* Check the water fill solenoid. Should be a definite click when activated. Water filling sound should be very clear.
* No water flow then check the water supply line if it's on.
* Final; this brewer needs service. Call your coffee vendor for advice.
Aloha, ukboy57

P.S., Older timers usually are reliable. It may have been set for a larger decanter or pump pot. The pump pots come in 2.5L and 3L for the big boys. Decanters are 10 cup and standard 12 cup. Check your office as there may be an unused pump pot or small decanter in a cupboard that got put away for making "too little" coffee. Try a brew in this smaller pot. Any change in pot size requires an adjustment to the timer. This is the only way to get "Less" or "More" out of the brewer. (Yes, if you have a "Pour Over" function for one time special brews. Check the manual for this option.)

You should call your vendor for service on any commercial brewer. (Especially if it's on loan from them)
*** the following is for information only as all repairs should be performed by a qualified tech.***

The DUAL has a start switch activates the timer (analog or digital) board which turns on the brew valve and heated water is sprayed over the ground coffee in the brew funnel. Coffee then drips into the decanter. Under filling is caused by un-calibrated timer or interment timing.
* The timer comes in two types; Dial (old) and Digital. If it's the dial then a simple turn of the dial will make less or more water flow to decanter. You MUST re-brew (no coffee, but use funnel) into the decanter or pot that you plan to use. Don't mix up different size pots as the timer is only good for 1 setting. Turn dial and brew once to check. Keep checking with a brew after each adjustment. Do a final brew just to be sure.
* The digital timer is a bit more complicated to adjust. Sorry, too many switches and options to go into it here. Check Bunn.com for a manual (FREE download) on line. Several methods are listed. The fill and stop is the easiest one.
* If it does not adjust or won't keep the set time then. Replace the timer. Digital timers tend to be sensitive to electrical storms. Analog timers have a dial and are more tolerant of electrical surges.
* Check the water fill solenoid. Should be a definite click when activated. Water filling sound should be very clear.
* No water flow then check the water supply line if it's on.
* Final; this brewer needs service. Call your coffee vendor for advice.
Aloha, ukboy57

P.S., The DUAL timer(s) ARE tricky to set as each brew size has to be set up and double checked (some 3-4 times) That means at least 6 separate settings. There is a copy over function but unless your brewing the same for both right and left, this copy function may not be suited fore your situation. (you may brew a smaller amount for the de-cafe side or even into smaller pump pots.) I've set up hundreds of these brewers but still have to use a cheat sheet (card with set up info) to get the digital timers right. *** These units may be locked out by the vendor *** You may still be required to call them to unlock the brewer.
* Final note; There is a BY-PASS valve on each brew head. Some are manual with a needle valve adjustment and others have a solenoid (similar to the brew head solenoid) This can affect the brew level too. Again, you will need the manual to set this up as there are hundreds of ways to brew in combination with the by-pass system. Ask about "Pulse brewing" for it's advantages.

After the first brew the machine should brew excactly the amount of water added to the water reservoir. Since the reservoir always keep half full then you should add the maximum amount you need in two steps.

These tanks can't actually be overfilled since all water poured in displaces the exact same amount of water coming out the spout. So, whatever amount of water you pour in, will be the same amount of water that flows to your pot minus the amount absorbed by the coffee grounds and filter.

Your problems sounds like an undersized (Non Bunn) filter, or clogged brew basket. To verify this, try pouring in only half the water for your brew cycle and wait for it to finish dripping, then pour in the rest. If no overflow has occurred, you simply have the wrong type of filter. If overflow begins again, you have a clogged brew basket, since no Bunn can flow too fast for the brew basket to keep up with it.

This is because Bunn filters are manufactured differently than generic store bought paper filters. They will flow faster, brew cleaner and stand up better than normal generic filters.
Remember, Bunn makes their OWN filters for good reason.
They made the first, best paper filters for drip coffee pots, and all others are just generic dioxin gas producing paper.

• Brews 3.8 to 7.5 gallons (14.4 to 28.4 litres) of perfect coffee per hour.
• Large 200 oz. (5.9 litres) tank provides back-to-back brewing capacity.
• Adjusts automatically to varying water pressure.
• For high lime areas, BrewLOGIC® technology calculates flow rate and adjusts brew time to maintain consistent pot levels.
• BrewWIZARD® technology incorporates simplified programming with a LCD display.
• Quickerinstall saves up to 30 minutes. Pot level, cold brew lock-out and tanktemperature set easily from advanced touch pad on front of machine.
• Electronic diagnostics and built in tank drain make service easier.
• Ensures coffee brew quality with cold brew lock out capability.
• Brew into decanters.
• SplashGard® funnel deflects hot liquids away from the hand.
• Coffee extraction controlled with pre-infusion or pulse brew and digital temperature control.
• Automatic warmer shut-off.

Remove the top panel and look for the yellow float, this controls the amount of water brewed, to adjust remove some of the washers on the float and test until you get the amount needed.

Try an experiment - brew a test cup, but use only a small amount of grounds in the brew basket (use a paper filter) [or else, put the grounds in the gold tone filter basket]. See if the machine makes coffee (albeit weak coffee). If it does not make coffee, see if the water is draining properly from the brew basket, or if it is leaking over the sides of the brew basket. Also, make sure the lid to the brew basket is completely open and in the correct position.

If you still get water only in the caraffe, replace the brew basket. The part costs about $11.95 with shipping - or even call Cuisinart to see if your 3-year warranty will cover the issue.

-Tha Mp3 Doctor

Inside of the front cover is a brew timer dial turn this counter-clockwise a little bit, then try brewing another pot. re-adjust as needed. Just watch where you put your hands in there.

This happens when the machine needs cleaned. Fill coffee maker with white vineger instead of water. Turn grind off, make sure empty pot is in place. Brew a pot of hot vineger. Repeat. Brew a pot of hot water. Repeat. This process removes mineral buildups inside machine. If you have access to filtered water, start using that to brew your coffee. I do and probably do this process 1 per 6 weeks.