I'm running a Vetrano on a timer and normally at walk up in the morning the grouphead static reading on erics grouphead thermo is 207-209 and the first flush is lots of steam and top temps of 210-212. about a week ago the walk-up reading would be in the 170s and a flush wouldn't get me above 190. I figured i have a vapor lock caused by a calcified vacuum breaker. it did correct itself after blowing off some steam. i ordered a new vacuum breaker and replaced the old one a couple of days ago. The old piece wasn't as gunked up with calcium as much as just having a dried out looking gasket where it seats in the silicone washer (i think). anyway it worked fine... for a day.

This morning the grouphead reading was back at 174 and after releasing some steam and running some water through the group i got it up to 204, but no higher and no steam / gurgling at the group.

My Pstat cycles on at .95 and off at 1.15. it is currently taking 8 seconds to heat up and 1:40 to cool down once it's warmed up to 204 at the grouphead.

i don't notice the fill coming on (so i'm assuming no leaks) and i don't hear any steam release inside the machine at idle

I must've done something to the machine when i replaced the insides of the vacuum breaker valve. I initially tried to remove the bottom piece of the valve, but it seems to be set in there with loctite or something and i couldn't get it to budge then i realized i could just replace the guts. This is really straight forward repair so it's hard to imagine what i could have moved or damaged.

Any ideas? Thanks all in advance... -Will

Will -

Or its possible the vacuum breaker wasn't the problem in the first place.

Remove the same parts from the "new" vacuum breaker and check your water level with a 1/16" wooden dowel. If I remember correctly, the level should be AROUND 5.0" from the bottom of the boiler. Maybe its time to clean off the level probe with a little vinegar or emery paper.

Interesting... i'll give it a try tonight. it's odd i could get it up to about 204 by bleeding steam and waiting, but then an hour a half later it would be back to 175. I'll let you know how it goes. Thanks Eric! -Will

It sounds like a possible thermosyphon stall. See the illustrated article I wrote on the subject:
Understanding and Preventing Thermosyphon Stall

Doesn't seem to be the water sensor. I ran a number of measurements, forcing refills in between and always came up at about 4.75" off the bottom of the boiler.

Thermosyphon stall would explain why i can get it almost up to temp for a while after a number of flushes but then a few hours later it's back down to 175 degrees. the longer it sits the more air is slowly entering the system. You don't think i'd hear a leak? i do remember seeing the tiniest bit of water occasionally at the top mushroom cap nut at that teflon washer. there is some scale there as evidence. I suppose i should replace that teflon washer and see what happens. Any other ideas?

Will -

I do believe that Randy G. is "on to something" and I was thinking that a higher water level would reduce the rate of heat transfer to the hx water. The temperatures you report are, for sure, in line with what others have reported when experiencing a stall. See this: http://www.home-barista.com/espre...r-scale-t6704.html .

Pics would be very valuable to others and don't forget to shut off your water supply before opening up the grouphead.

This makes sense... the thermosyphon is compromised which is keeping me from getting the temps above 204 and the huge drop after a long idle. I can eventually get it up to 204 but not higher because I'm getting HX water that is cooling too much on the way to exit because the whole circuit isn't getting hot enough without the proper thermosyphon.

Wow... i just read your post on checking / descaling the mushroom... it's like "The Complete Idiot's Guide to Descaling your E61 Grouphead" GREAT reference. THANK YOU. I have to track down the big wrench and i'll give it a shot. I have some Dezcal for when i get the nerve to try a full descale... did you ever work out how to descale a Vetrano?

did you ever work out how to descale a Vetrano?

No, because there exists a difference in experience between what I have seen in practice and what other users have reported. The suction line from Vetrano's pump to the machine's water connection is M5x3 teflon tubing, i.e. ABOUT 1/8" inside diameter. When this line is pressurized with, say, a regulated pressure of 2.50 bar, there is (obviously) no problem with pump performance. When you try to "suck" through this line, it is another story altogether.

In addition, the Quickmill machines (and all others) are fitted with a spring-loaded check valve upstream of the hx inlet and a descaling pump needs to develop sufficient pressure to overcome this valve at a reasonable flow. My little pump could not do it -

Well... descaled the mushroom and thanks to Eric's detailed instructions all went as planned and was very simple. Had some scale that looked like barnacles on the mushroom and after, now have clean brass. I'm having extension problems posting pics, so will do that another day. I was very optimistic, all back together, no more tiny droplets at the nut, lever super smooth... went to dinner and came back to... 174 degree group back to square one, at least i have a clean group and a new vacuum breaker! what's next, or am i shipping this thing to Chris?!?

Will -

Remove the mushroom again.
Install blind basket to seal grouphead.
Get as much water out of the hx as possible.
Pour in some white vinegar and let it sit for a hour or so with a little heat - not full on.
Reassemble & flush.

On the CHANCE that the thermometer could be reading erroneously, stick the tip in some "just off the boil" water.

edit - and what is the boiler cycle time when group temp is low - your original cycle time posting was very reasonable? There does exist this quick descale procedure - http://www.home-barista.com/espre...descale-t3080.html although I would need to send you some fittings to swap out on your pump's suction line.

I think the thermo is OK, because it reads the temp dropping into the 170s after a long idle but then i can still get it back up to temp by a series of flushes, and as high as 211.5 eventually.

I don't know if this could get air into the HX, but I have a pretty bad drip at the lever when pulling a shot. I'll replace the bushings.

Will time the boiler cycle this evening (so it has time to drop down to the low levels). It's been 45 minutes since my last flush and i'm 209 at walk up and it flushes up to 210.5/211.5.

I'll do another descale of the group as you described. Few questions:

Isn't this the same procedure i just did?
Why vinegar instead of dezcal?
I assume i should resoak the mushroom etc again?
How do i get water out of the HX and not just the empty the group?

Regards, Will

Cam lever bushings are only exposed to the hx during a shot - the closed brew valve seals that area.

The idea behind getting water out of the hx is to make the descaling solution be at the proper concentration. It does not matter whether you use dezcal or vinegar. For no particular reason do I prefer vinegar. You do not need to resoak the mushroom as long as you can see light through all the holes.

Just returned home and the machine has actually held its temp! don't know what's up. maybe there was a big piece of scale that finally dislodged itself after the descaler ate away at it a bit? It's at 210 and flushes OK. Something is still going on because if i follow my usual routine (flush to 207, wait 2.5-3 minutes, flush again to 207, wait 30 seconds and pull, which will give me a shot at 201) the first flush is fine and i shut it off at 207, then after the rebound when i flush again i can't get above 206 (normally goes up to almost 209). it seems to be dropping temp much more quickly as well.

So, i think i'll try your extra long warm descale on the HX, maybe try to blow all of the water out of there to make sure it fills up with descaler. We'll see what happens. It'll have to be next week... heading out of town in the morning.

Have a great Memorial Day weekend all! -Will

I'm bringing this thread back from the grave because I'm having a similar problem with my Quickmill Anita. I have it on a timer set to come on in the morning and evening. Most of the time this works fine, and grouphead temps idle at around 208 when the machine is up to full temperature. However, every once in a while, group temps will be down in the 160 or 170 area. I have to flush the group for a while to get the temp up again, and then wait several minutes for the temp to come up to normal. When flushing the group, no water comes out for several seconds, then eventually water starts to flow normally.

Also, the last few days I've started to see the temps at the group idling much higher than normal, sometimes up to 215 or more. Again, flushing some water through the group gets the temperature to come down, but at first no water comes out and then it starts to flow normally after a few seconds.

I'm assuming this behavior is being caused by thermosyphon stalling. I did run some descaler through the HX and boiler a couple of months ago, and I also did an HX only descale recently, so I'm pretty sure there's no scale blockage. Any other ideas on what would cause the stalling to happen? Do I just need to run lots of water through the machine every time I flush?

For sure, NO.

I believe your problem is caused by a leaking (even ever so slightly) brew valve. This would also be evidenced by a slightly longer time of pump running before any water appears at the grouphead together with a change in pump sound.

Nice to have a thermometer, eh?

erics wrote:Nice to have a thermometer, eh?

No doubt! The group thermometer is a brilliant invention.

So does this mean I need to tear apart the brew valve and replace some seals? Any diagrams or pointers on how to do that? I haven't tried to take the group apart before.

It is very easy - see this: Checking an E61 Espresso Machine for Scale

The first pic shows the valve and the tools needed for access.

Awesome, thanks!

So basically I just need to pull out the mushroom and soak it in vinegar, or do I need to pull the brew valve out of the mushroom too? Do you think the brew valve may be leaking because of scale buildup, or do the seals need replacing?

I'll try taking the machine apart soon and let you know what I find. Thanks for all the help.

No, I wasn't NECESSARILY advising any descaling but it's almost like - what the heck? After you remove the top nut and the gicleur screen but leave the gicleur in place:

Unscrew the mushroom with the lever in the down position - still you will feel the mush turning against the spring end.

The spring and brew valve lift out with tiny fingers or the needle nose pliers. If warranted, soak the mush up to the threads in a cup of vinegar for a couple of hours and clean with a green scrubby under running water. Hold the mush up to the light and you should see daylight through the 4 feed holes on the underside at the rim and, of course, the gicleur itself. It is, of course, easiest to replace the brew valve in its entirety (about $15 I think from CC or Great Infusions) but you can also simply replace the rubber valve face.

Thanks, I'll order up a new brew valve from Chris.

Looks like this is the part I need.

http://www.chriscoffee.com/products/home/e61groupparts/groupbrewvalve