How to adjust the water so it does not over fill the pot

Over Boiling or constant heating of tank water is an indication of a shorted thermostat (or out of calibration). Call your vendor for service. (especially if this equipment is on loan.)
*** the following is for information only. Repairs should be performed by a qualified Bunn Tech. ***
* VPR's and similar machines REQUIRE a pre-fill and heating period prior to brewing. This means it's sitting on a level table and filled with water until water sprays from the brew head. At this point the unit is plugged in and the heater is turned on (there may be some water discharge from brew head as the water expands). Ready light will come on in about 15 mins.
* To Brew; Place coffee grounds in filter, place in funnel and brew head, clean empty decanter under funnel, slowly pour one full decanter of water (cold or hot) into brew tray. Do not overflow tray. Allow water level to sink before adding more water. Only fill with one pot as an equal amount will come out the brew head and funnel.
* Make sure the decanters are all the same size. do not mix a 12 cup pot with a 10 cup pot. One will over fill and the other will under fill. Make sure they match (in cup volume) FYI; Thermo Air pump pots are usually bigger than one pot. Typical filling only to 3/4th of the container. (I think most are in 2.5 to 3 liter sizes)
* If your not getting a full pot then the brewer was partially empty. The second brew (if done within the next hour) should come out full.
* If your still not getting a full pot then the water is leaking or is boiling off. Does it always steam from the top? Thermostat is shorted. Unplug the brewer and call vendor for service.
* Final; Follow the Bunn set up and care instructions (manuals from Bunn.com for down loading. *FREE*)
Aloha, ukeboy57

PS; There is a slight chance that your thermostat is set too high. There is a dial on the thermostat that can be turned counter clockwise to lower the temperature of the brewing water. Water should be about 190-205 F for coffee. Tea drinkers want 210 F which is too close to boiling point of water. If your in the mountains (+2000 feet) then the boiling temp will lower. Was it possible the brewer came from a low (sea level) location and moved to higher altitude? Then the setting is off and must be set lower (a fine adjustment). But note that if your on the top of a high mountain (like Haleakala, Hawaii) then it has to be set a lot lower and you will only get luke warm brews at 9,000 feet!. Adjust the knob clockwise to get it to boil. Then back it off counter-clockwise a bit till it stops boiling. Make another brew to check if the reheat comes to a boil but stops after a minute or so. It should not boil on longer than 2-3 mins. Back it off a bit more if it does. Brew again to check. If none of this works then you will need to replace the thermostat. If your at a really HIGH altitude location, then you will need a specially adapted high altitude brewer. Call your coffee vendor for advice.

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.)

The coffee dispensing valve is stuck open. It may be due to Calcium deposits.
Descale the machine or manually clean the dispensing valve and the diffuser disc that unscrews to be removed. This diffuser is visible just above the coffee pot.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edward_bbd2c7ff4ee1828a

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.***
* Since no brand or model given. I suspect this is a commercial coffee brewer as it probably has a plumbed in water line. Bloomfield, Curtis, and Bunn are the most common. I'm using Bunn CWTF for this example but it covers most other brands too.
* The CWTF 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 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., 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 there is a way to use the "Pour Over" function for one time special brews. Check the manual for this option.)

If u haven't cleaned it out using 3/4 vinegar to 1/4 water, some times this will happen. after running this thru ur coffee maker, (u won't believe the junk that comes out), then run full pots of water to rinse out (2x's). This should help it perform better.

First brew a pot without water, to find your current level. Next open the faucet and check the water flow, if it has a nice flow no stopping or spurting, then your water connection is good. Now adjust the brew level, the adjustment instructions are on the inside of the front panel. If after making adjustments you get the same result then the solenoid is blocked.

Fill the bottom to the line with water. Put two cups of rice in the top and two cups of water. Put on stove top on high until lower water is boiling, turn to medium heat. For white rice check after about 20 minutes, if water is assorbed and rice is tender, fluff with a fork...eat. If it needs a few more minutes of cooking, no problem.
Brown rice will take about 45 minutes.
I have used my stove top cooker for at least 35 years...ordered it with box top and some money from Comet Rice.
Pat

There is a brew timer on the left side of your machine near the heater switch. you need to remove an access panel to access it. turn this down a little, let the water heat up, then try another brew. Adjust as needed, brewing another pot between each setting.

that model may have a digital timer that is acssed using the panal swithes get the number for wilbur curtis from thier web site they will talk you through it {simple} the other style timer is a potentiometer type To adjust first unplug brewer, look behind either the front panel or top cover for a dial with numbers around it. turn the dial down slightly brew a pot of water see where the water level comes keep turning down till desired level is reached

Most likely you have some lime-scale build-up. When you brew a pot, it only brews the same amount of water that it takes in. When the inlet is restricted with scale, not enough water is let in for a full pot. You've adjusted the timer, so when you clear the inlet, you should set it back down so you don't overflow the pot.
It also could be just something cought in the inlet orifice (result is the same). Either way, start where the water is connected to the machine and go from there. Sorry I can't be more specific, scale is an elusive devil.
In the future, try using soft water.

Good luck