I'm wondering if anybody could offer any advice. My machine began leaking a week or two back and I finally decided to narrow it down.

It leaks while heating and also once fully heated. If I fill the water reservoir at night, it will be mostly empty by morning if I leave the machine on overnight. (Always run off the water tank). Water dripping out of expansion valve (tightened as much as I can), and steam and water drops leaking out of the hose shown in the picture:




Short video of the machine heated up and leaking:
Any idea where to start to get this fixed? I have some parts, but not the expansion valve. I do have assorted o-rings and gaskets as well as a couple solenoids that I ordered a few months back.

Thanks.

The hose you referred to in the picture is the vacuum breaker. What you can do is open it up and replace the o-ring on it. You can refer to this thread for more information:

La Marzocco GS3 vacuum breaker cleaning?

You'll probably want to replace the expansion valve.

bob

Ok, I cleaned the needle and the seat inside that vacuum valve. The o-ring was in good shape. Seemed to fix that leak.

Now I just have the expansion valve to work on tomorrow. I tightened the crap out of it and now it's being a pain in the butt to loosen, everything slips on that slick brass. I may just take it off higher up.

You'll have to remove the entire valve and not just the circular part when you replace it anyway, so I wouldn't bother too much about loosening it at this point.

bob

I would suggest you read the manual as regards the adjustment of that expansion valve because what you did could send the brew boiler into unusually high pressures when warming up from cold.

An easier way to adjust the valve is to adjust the pump's relief/regulating valve to a discharge pressure of 11-12 bar using a portafilter and coffee filled basket as you would normally brew. At this pressure, adjust the expansion valve such that you see a drip . . . drip . . . drip. Turn the pump's adjustment back to 9.0 bar and the expansion valve should show NO leakage.

If your particular GS/3 is fitted with a drain valve on the brew boiler, this is a one-time adjustment that should be checked every six months(?) for proper operation.

It's normal for the vacuum breaker to not seal properly and leak after several months or years of use, depending on the mineral content of your water. Cleaning it or replacing the O-ring or replacing the inner mechanism is a regular maintenance item.

The expansion valve leaking isn't normal, but it's possible for the valve to get clogged if there's debris in your water (Do you filter your water?) or if you're putting hard water into the machine (Do you soften your water? Do you know the mineral content, especially hardness?)

erics wrote:I would suggest you read the manual as regards the adjustment of that expansion valve because what you did could send the brew boiler into unusually high pressures when warming up from cold.

I agree with Eric -- never run your GS/3 with the expansion valve closed. It should be adjusted so that the coffee boiler pressure never exceeds 12 BAR.

erics wrote:An easier way to adjust the valve is to adjust the pump's relief/regulating valve to a discharge pressure of 11-12 bar using a portafilter and coffee filled basket as you would normally brew. At this pressure, adjust the expansion valve such that you see a drip . . . drip . . . drip. Turn the pump's adjustment back to 9.0 bar and the expansion valve should show NO leakage.

I agree that when the expansion valve is properly adjusted, it shouldn't leak unless the pressure gets up to 12 BAR. Then you'll see a few drops coming out of it.

Since you're seeing drops coming out when the valve is completely closed, it's probably clogged or the seal is shot. I'd try removing the entire assembly and cleaning it.

I have the utmost respect for Eric, but I'm not in agreement with his procedure for setting the expansion valve. I wouldn't do it with coffee in the portafilter. The proper procedure is outlined in the GS/3 manual. Start with the expansion valve set so the two black marks on it are aligned. If the marks are gone, screw it all the way down, the back it off about 1.5 to 2 turns Then adjust the bypass valve on the pump so you get 9 BAR at free flow (no portafilter). Then let the group run for about 20-30 seconds. When you shutoff the group, the heater will come on and the pressure will rise. Adjust the expansion valve so it peaks at 12 BAR and never exceeds that level.

Another way to do it is to set the pump bypass to 9 BAR, insert a blind basket in your portafilter and run the group. Adjust the expansion valve so the coffee boiler pressure reads 12 BAR.

I understand your frustration with trying to turn the expansion valve's brass tube. It isn't easy. I usually wrap a pair of pliers with electrical tape and apply pressure as gently as I can to turn the tube. It's probably inevitable that the tube will get scratched, but you must not deform it.

erics wrote:If your particular GS/3 is fitted with a drain valve on the brew boiler, this is a one-time adjustment that should be checked every six months(?) for proper operation.

Actually, you should check it every time you use the machine. The pressure usually rises to the max 12 BAR when the heater comes on after you pull a shot. It's always good to check that it's not going over 12 BAR. If it does, the expansion valve needs adjusting.

I'm not sure what Eric means by referring to a drain valve. You don't need to drain the coffee boiler to check or adjust the expansion valve, but you do need to drain the coffee boiler to remove the expansion valve. There's no drain valve on the brew boiler. You drain it turning off the machine, letting it cool completely, removing the group head bleed screw (under the black plastic cap on top of the group), and opening the expansion valve until water streams out of it. When you refill the boiler, set the expansion valve so the black marks are aligned (or, if they're gone, tighten it all the way and back it off 1.5-2 turns), insert the bleed screw and allow the boiler to fill. After the boiler fills, you'll have to loosen the bleed screw slightly to let the air out, then tighten the screw. It's a good idea to replace the copper washer under the bleed screw when you do this.

I'm not sure what Eric means by referring to a drain valve.

The Strada and the current GS/3 boilers share the same part number (L.1.001.02). The Strada does have a drain valve for the brew boiler so I figured (incorrectly) that "what's good for the goose is good for the gander". I do realize that the configuration on the right side of the brew boiler is a little congested but . . . who knows . . . possibly retrofittable?

I see. Yeah, it sure would be nice to have a dedicated drain plug for the GS/3 brew boiler. It's a pain to unscrew and recalibrate the expansion valve.

But a retrofit would be very challenging on either side. Not sure it's feasible.

Well I got the expansion valve off. Cleaned it up and reinstalled it and still leaking. I'll order a new one up tonight.

Just curious though, when I put the valve back together, it was leaking from the threads where it screws up onto the line and not out of the bottom of the valve.... Regardless of how tight I screwed it on.

Remove the valve in its entirety and inspect the end of the machine's line. I'm guessing that the threads on the end of the valve are 1/4" BSPP and the machine's line has a mushroom shaped compression fitting. There is no sealant material because the mushroom fitting which is soldered onto the machine line is "compressed" into the valve adjustment body via the nut on the machine line.

I watched your video and that rate of dripping is PERFECT for a brew boiler pressure of ~12.0 bar.

If you remove the entire valve and disassemble and post some pics, help (if any) would be a whole lot easier. Plus, it would benefit GS/3 owners with this same problem in the future.