How do I get the BUNN VPR coffee maker to brew a pot of coffee? There are two switches; one for the lower, and one for the upper warmer. Do I first have to fill the tank ALL the way before it brews? Please help!

VPR is a pour over "Volume Displacement" brewer. Required to completely fill the inner tank and heat prior to using brewer. BEFORE plugging in unit, water must be poured into upper tray and with brew funnel and empty pot in place. Keep pouring water into top fill tray until water drips out of brew funnel. Plug in VPR and allow it 15-20 mins to heat up. leave the pot as there may be additional water dripping. Remove power if there is any water spilling out from other places like the top pan cover or bottom of machine. With the initial heating done, take a full pot of water and slowly pour into the top filling tray. HOT steaming water should come out of the brew funnel to fill the (empty) pot. Prep is done and the machine can be used to brew a pot after 10-15mins of reheat time.
*** the machine you have needs to be checked for leaks in areas mentioned above. Water should only come out of brew funnel (if not present then the brew head or if that is missing then the brew pipe. All will need to be replaced prior to brewing.) Leaking under machine is an indication of leak(s) in pour tray,tank,tank cover, gasket, probe gasket. This machine like any used equipment should be checked out by qualified tech prior to use. Be aware that coffee vendors sometimes rent or loan brewers to customers.

try hitting 'brew' until all the water evaporates, or look for a 'leak' valve to empty it. usually on the bottom or the side near the tank.
-swish-

While this brewer does have a reservoir that keeps a couple of pots worth of water hot for brewing you can get a cooler second pot if you brew directly after. You should hear the brewer heating up after brewing. Try waiting until it is back to temperature before re-brewing. If that heating takes more than a few (3-4) minutes then you probably have a problem with the heating element and the water is only being heated by the "keep warm" heater.

This machine has a reservoir that holds about 2.5 pots and keeps them at brewing temperature. Therefore you should pour in 3 pots (with a pot in place under the filter basket) until water flows from the basket. Then, and ONLY then, it is safe to plug in the brewer. If you plug in the brewer BEFORE filling the reservoir you will burn up the heating element and will have to have it replaced.
After the initial filling and heat up (about 20 minutes) you are ready to pour through a pot of COLD water through and brew.

Try running a quarter-pot 50/50 solution of white vinegar and cold water through to clean out calcium deposits in the pump system. Use a clean filter to catch the pumped debris. When pumped through, let cool somewhat, and reuse the cold mixture again twice more. Pour out the vinegar solution and run several cold water loads through to wash out the taste. Hope this helps!

your tank is leaking
Please Follow LINK for parts etc

Make sure you are using the type of commercial coffee pot like the one in the picture. They don't have to have to be plastic with the metal bottom, they can be all glass. The commercial pots are heavy duty and usually disperse the heat well.

If you are using commercial pots the only solution without replacing the warmers is to put three pennies on the warmer and to put the pot on top of them. The pennies will get hot so don't forget and grab them but the pennies help to move the pot just a little way away from the direct heat.

You can either replace the warming element with a new one, or some people put 3 or 4 pennies on the top of the warmer tray. Don't laugh- this really does work!

Try connecting two elements in series. See if this keeps it hot enough. (One switch controlling both burners.) See if another brand of burner will fit in the hole. Check to see if the wattage is lower.

I own a bunn and my brother's business owns 2 of these. The rule of thumb as he was told by the salesman is 2 oz of coffee grinds per 48 oz of water.