Hi All-

Picking up working on my La San Marco 85E. I think I'm down to my last issue,

Everything seems to come on OK. Takes a little less than 20 minutes from stone cold to trip the pressurestat. I need to press the shot buttons a few times before it will pour water, but once "primed" everything works until the cows come home. Unless I let it sit for >10 minutes. That's where the problem is.

Once it's hot, pressing the buttons to deliver water WILL cause the pump fan to turn but it WON'T take up water and it won't deliver the shot.

If I use the hot water valve for about a mug's worth of water, the fan will come on and the pump will take up water. THEN if I press the shot buttons, it will prime for the first couple presses and then deliver normally after that until the cows come home. Or until it sits again for >10 minutes.

Any idea why this is happening? In case it's relevant, the pump is drawing from a bucket/reservoir. When it sits for a while, the hose to the pump from the machine, and to the reservoir from the pump are HOT, too hot to touch. And bubbles and I believe a small amount of hot water are coming out the hose that is in the reservoir. Could I have a bad valve somewhere?

Thanks for any input!

CantComplain wrote:In case it's relevant, the pump is drawing from a bucket/reservoir. When it sits for a while, the hose to the pump from the machine, and to the reservoir from the pump are HOT, too hot to touch.

Do you have a one-way check valve for the water inlet? It sounds like the inlet line is drawing water out of the machine; if so, that could explain why you need to draw water first because air is being introduced into the thermosyphon loop.

I don't have anything that's not part of the espresso machine itself. Is that what you're referring to, as in something that would be part of a water softener or something like that?

There is a component in the machine called a "check and safety valve". See http://www.espresso-machines-me.com/dow ... ACHINE.pdf page 23 item 25.

So I'm trying to figure out if you're saying that I'm missing a component, or that a component has failed. Also, if this were plumbed in, do you think the pressure from the line would prevent this from occurring?

Thanks so much for weighing in. I appreciate the advice.

CantComplain wrote:Could I have a bad valve somewhere?

Absolutely, positively, no doubt about it. The check valve between the pump and the heat exchanger inlet is jammed open and not performing its function.

Fixing and/or replacing this valve will solve your problem.

Here is a better pdf overview.
http://www.michaelo.com/uploads/1/9/9/6 ... ircuit.pdf

erics wrote:Absolutely, positively, no doubt about it. The check valve between the pump and the heat exchanger inlet is jammed open and not performing its function.

Fixing and/or replacing this valve will solve your problem.

Awesome, thanks for the information. I tore into this item labeled "no return valve body" and sure enough it appeared to be relatively frozen. Easy enough to clean out and thanks to the PDF Summer posted, it looks like I can go to the local hardware store for the O-rings.

I can't find any documentation for how to adjust it--can anyone provide any input? It's a large barrel screw that puts tension on a spring pushing against a valve. If the pressure builds, it trips the valve and dumps the water to the waste tray. So what am I shooting for in the adjustment?

. . . it looks like I can go to the local hardware store for the O-rings.

That would not be a good idea. Try and source the original parts as the material specs for O-rings vary. LSM parts should certainly be available from one of the sponsors of this site - this person comes to mind - http://www.espressoresource.com/ .

The valve you are describing in your post is the OPV, acting as a thermal expansion valve. It is NOT the valve that is causing your problem although it may very well be in a failed state. That OPV is adjusted to go drip . . . drip . . . drip into the drip tray at a pump discharge pressure of 11-12 bar.

The portion of the OPV that is causing your problem is part number 205130 or one of its surrounding components.

Post some pics of the internals of your machine.

Thanks erics, I'm sure you're right after noodling what a valve in that position would do. Darnit.

I put some pictures below of the components I would think could be related to the issue. Do you think it could be the manual fill valve in the bottom picture? Looks like there's a check valve on that--guess I'll strip that apart next. These may be the last components I didn't clean out, guess there's no short cuts in the world of espresso....

OK, that was it. I replaced the one way valve shown on the bottom pic from my post above. Voila!

One thing, as long as I have you guys: can anyone id this valve? I took it off and cleaned it when troubleshooting the other stuff and it looks like it developed a slow drip from the little nub in the middle.

It's on the far right of the tank, at the bottom. It looks like the anti-vacuum valve at the top but I can't find it on any of the parts diagrams. I'd appreciate any help.