I have a La San Marco 85 16M . When I press the fill valve water shoots out of the pressure relief valve. Any ideas what could be wrong?

Your boiler is full of water

How do I fix that? I'm new to this so trying to learn

Have you been pressing the manual fill lever in order to maintain the right water level in the boiler? Have you over time, pressed it too often that you eventually filled the boiler full?

A few things need to be known about how you operate your machine, before a correct diagnosis and solution can be offered.

The water coming out of the over pressure valve usually means your boiler is full. Maybe you pressed the fill lever too much. If it was the first time you pressed it, then the boiler was full beforehand.

The level in the boiler is controlled by the auto fill circuit. Check the probe and that it isn't covered over with crusty scum. Otherwise if it happened to creep up overtime, then it points to a slow leak past the fill solenoid.

Let us know how you use it. Maybe it's a 'new to you' used machine. If that's the case you bought it with this problem.

It can be fixed.

As you may guess I am new to this. The machine is at work. It is hardly ever used. A couple of weeks ago I went to use it and noticed it was leaking water.
The vacuum valve stem was down and leaking water.
I shut the water off and ordered a new one.
After I installed it I went to the machine. I turned it on and when I operate the hot water lever, I only get a small amount of water and then the little piston on the vacuum stem goes down and water leaks. If I press on the water fill lever it pops right up and water shoots from the pressure valve.

Any help you can give would be appreciated. I would love to get this fixed and start using it more. My work doesn't want to spend the money to get it fixed and fear they will toss it away or sell it on ebay.

Ok I understand a bit more now.

To empty water out of boiler without any tools, open hot water spout and let the machine heat up. The water will expand and will go toward what is open. You have two things open at this stage, the hot water tap and the vacuum breaker valve. When you get water starting to go out of the vacuum valve as its heating, just pull the stem in order to close it and to stop water coming out of it. Now only one thing is open and you can empty boiler in this manner. Just close the hot water tap when the water is reduced to about half.

Next you need to deal with auto fill circuit. Either the probe is crusty and needs to be cleaned or the fill solenoid has a leak. My bet is the solenoid.

If the probe was crusty, the pump would be working and trying to keep filling the machine when it is turned on. You don't mention anything about it so I'm only guessing.

With the machine on and the hot water valve open, I only get a drizzle of water.
When I press the button to make coffee It does start and I do get espresso but it is not hot. warm at best.
If I remove the fill probe wire, water once again shoots out of the relief valve.
Does that sound like a solenoid issue?

No water from hot water tap or steamer but do get warm water from the espresso maker. The boiler heats up but not too hot when I touch it.

I found a drain valve so I managed to drain the water. Then I disconnected the fill solenoid and measured between the leads it was not open.

I connected everything back up and the machine started working. It took a good 15 minutes to reach temperature but the fill went to the line and everything seems to be working okay. Thanks for your help.

Great to hear it's working again.

Now keep an eye on the level in the sight glass. If it starts to creep upwards, then you have a slow leak past the fill solenoid.

Is that usually the solenoid that is going bad?