Delonghi EC 820B leak from the bottom edge of the Boiler outlet/ Infusion assembly.

I just fixed a similar problem with my Delonghi Eco 310. Halfway through making a cup water stopped coming out but ran out from underneath.

This is how i fixed it:

First I checked the little tube that goes from the pump and anti drip valve into the boiler unit. There is a clamp on both ends to remove before you can take it out. First fault can occur here, check the black little O-Rings that might still stuck inside the connectors, if they are worn out they might need replacing.
Then check the little tube for any damage, even any fine tiny cracks can lead to a big leak as 15 bar go through it.
In my case there was no damage there, also not on the tubes that come from the watertank into the pump.

After I checked all that and it seemed fine, I turned the machine back on again with open top (careful of any electrical contacts!!!). Then I saw that water and steam came out of the anti drip valve. It seemed the water got sucked into the pump, pumped into the boiler, heated up there and put to 15 bar, but because the valve was broken the water didnt actually came out but searched the easiest way, which was the broken valve, that regulates the pressure. I went on a site for delonghi spare parts, bought a new valve for £5, replaced the old one and -tadaaaa! It works again!

It seems to be the one way valve which is broken. You can buy those from ebay by looking for "one way valve" Since this is an advanced repair, I can't tell you everything in case of damage done to yourself while trying to repair the machine.

COFFEE NOW!!!!!!! the coarser the grind the easier it should brew. is the strainer cup free of debris and build up?

Do you have the manual? Clean the boiler outlet, filter, nozzle and descale unit. Instructions in book.

Delonghi machine is 6600 is an Italian machine in a very magnificence I think if there was a leak from the boiler in this case you change Geskt enter and exit first and this process is easy, either that the problem is in the boiler in this case I advise you reference to the nearest power of attorney own

Here's how it works....
An initial short run of the pump draws water from the reservoir into the boiler where it is heated by an electrical heating coil. There are two outputs from the boiler, one from the top runs through a pipe to a steam valve. When the steamer handle is turned, the steam valve opens and steam is piped out through the steam tube for frothing milk. The second output from the boiler is on the underside and is stopped by the normally closed flow valve. When the water in the boiler reaches the right temperature, a sensor switches on the OK light. When the light is on, the user pushes the pump switch and more water is pumped from the reservoir. The pressure in the boiler increases because the pump is trying to push in more water and this forces the spring loaded boiler flow valve to open allowing hot water to run out. As the sump filled with ground coffee is fitted to the boiler output, the water is forced through the coffee and out of the sump where it pours into a waiting cup.
When enough coffee has been poured, the user switches off the pump. The boiler pressure falls and the spring on the flow valve pushes the valve shut again. ------------ The first three steps aren't strictly necessary for disassembly however if you're using a long handle screwdriver then removing the base makes it easier to gain better access to some of the screws.
Step 1. Remove the screw on each base arm.
Step 2. ... then lift and remove the arms.
Step 3. Remove the two screws on the base of the unit. Unlike in this photo I would recommend you avoid resting the machine on its back unless you are sure it has been completely drained. The black plastic base can now be pulled away allowing easier access to some of the screws that will be removed later.
Step 4. Undo the two screws on the top rear.
Step 5. Remove the coffee tamper by pulling and twisting.
Step 6. Remove the three screws. These are anti tamper screws and are star shaped with a nipple in the middle.
Step 7. With these screws removed, the top may be lifted away. The hotplate on the top section is still connected by a couple of thin wires so lift it carefully.
Step 8. To help with shifting the top out of the way, disconnect the hot plate/boiler heater connection. This will allow you to push the top of the unit away giving you the room you need to get inside.
Step 9. Unscrew the electrical safety earth and move the earth wiring out of the way.
Step 10. Use some long nose pliers to pull out the circlip that holds the boiler inlet pipe in place. Pull out the pipe to disconnect it from the boiler once the circlip has been removed.Step 11. Unscrew, remove and clean the diffuser.
Step 12. Remove the two screws . The black plastic underside casing can now be pulled away (plastic tabs need to be pushed aside ). Step 13. Pulling away the plastic underside once screws and tabs are removed.
Step 14. Loosen the four black Torx (star shaped) boiler screws . Water in the boiler may leak out at this point so ensure the unit is upright and a towel is placed underneath.
Step 15. Remove the four nuts (three arrowed) from the underside of the boiler unit.
Step 16. Lift up the top of the boiler assembly along with the steam outlet and place to one side. The two halves of the boiler assembly are sealed with a rubber gasket which should remain attached to the upper housing. Make sure this is properly in place when reassembling.
Step 17. The lower boiler assembly can now be lifted out.
--------
to get more detailed help click this link directly.it has all the required instructions and pictures to disassemble the unit.the model number in the link is bit different from yours but the system is very same so it will help you
http://www.r3uk.com/index.php/tech-tips/34-disassembly-guides/129-delonghi-ec710-coffee-maker-disassembly-and-repair
click on the link above directly.
This will help. Thanks please keep updated.please do rate the solution positively .thank you for using fixya.

You don't have to wait 15 mins. just a few minutes, then run some hot water to warm up the portafilter and dry it up, fill it up with coffee and when you get the gree light again, make your espresso . You will have to have a good fine coffee and make sure to pack the coffee really good and don't leave any around the edges , so could make a good seal. If you have steam coming out of the machine , is maybe to hot and is ready to brew . Cool down the machine after use, run water through it and let the steam out of the nozzle.

You need to contact Delonghi and order a part. This is the steam/water outlet assembly. This part includes an electronic solenoid which controls the water and steam output. I have had this problem 3 times. You may find the steam/ water is very loose when you try to wobble it sideways. This is the indication as to what is the problem, (as mentioned above).

Buy another one there like 10 bucks...

Could be scale build up. Do you have well water? You should run a descaler or white vinegar through the unit often to keep the boiler outlets clean.

Unless you are saying that the pump just doesn't run, ie, no noise, vibration, etc. Then, thanks for the warning that their pumps are bad.