E61 Giotto troubleshooting keeps making it worse

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
decrem
Posts: 28
Joined: 5 years ago

#1: Post by decrem »

Help, I'm stuck.

This is a Rocket Giotto Evoluzione v2 (rotary pump) and I'm using the water reservoir. I'm the second owner (3 years). This past few weeks have been my first times unscrewing pipes from the boiler and changing anything in the grouphead. I'm a newbie to espresso machine repair, but I'm an engineer and I'm generally comfortable making mistakes, which is perhaps a cause of these problems.

TL;DR: Problems
[1] What might this sound be? Video below
[2] What might cause 8 bars of pressure without the portafilter?
[3] If I backflush with a blind filter, the water does not come out of the discharge tube.
[4] the machine takes far too long (3+ hours) to come up to temp. When I flush water through the grouphead once, it comes up to temp quickly

More info:

[1] What might this sound be?
This happens after the hot water is open for a while (or I've emptied the boiler) and the machine begins to fill the boiler again. It does not happen when I run water through the grouphead. (I have not tested in the past 24 hours due to some of the other problems.)
[2] What might cause this high pressure without the portafilter?
- with no portafilter attached, run water through the group, 8 bars of pressure, ~200-205 degrees. (Why is this pressure so high? It was at ~4 bar last week)
- with a tamped 18g basket, run water through the group, it's like normal at 9.5 bars and ~200-205 degrees. Shot tastes great. (Note: i am afraid to test this again due to problem #3)
- with no mushroom in place, and water running through the group, the pressure is 0
- with the mushroom in place, but no preinfusion valve or drain valve, it's still 8 bars of pressure.
I have no way to tell IF the gauge is working or not, but the fact that I get 0 with no mushroom and 9.5 when there's a tamped basket makes it seem like it's at least getting the extremes right.

[3] If I backflush with a blind filter, the water does not come out of the discharge tube.

And -- the original problem -- [4] the machine takes far too long (hours) to come up to temp. When I flush water through the grouphead once, it comes up to temp quickly, where I can only assume my attempts to fix have caused the other issues.

I've changed the following inside the mushroom:
- upper portion: the gicleur, the gicleur screen, the brew valve and spring, the mushroom o-ring, and the 2 teflon washers.
- lower portion: the preinfusion valve (NOT the spring), drain valve and spring, and the bottom drain spacer, plus the two teflon washers
- middle portion: the operating cam, the cam washers, and the spring.
To eliminate variables, I've put the originals all back that made sense. Things I couldn't put back include the gicleur screen, the grouphead o-ring, the teflon washers, and the cam shaft rubber gaskets. The grouphead o-ring that I've installed is not the OEM one (rocket uses a green one), rather it's a generic Viton from Stefanos, of which I've tried both thicknesses that they offer. Reinstalling originals hasn't changed anything.

Things to note:
- The pump works and is quiet when I lift the lever to start brewing. No weird noises there.
- I have a whole house softener with high pH and this machine is using the reservoir. After softening, my TDS is extremely low. Due to the softened water and the high pH, per the water faq, I probably shouldn't have scale. But I'm not sure how much scale was in the machine before I purchased it. The mushroom showed some green scale on one side of it.
- I've descaled three times in the past few days, each time using a slightly different (improved?) technique, mostly because I assumed the problems were due to dislodged scale. I've been trying to pay attention to only running the pump for a minute or so before shutting it off for a while, to try and not overwork the rotary pump.

The machine was working as recently as three days ago.

My plan to solve #4 was to ensure there was no scale. Here's what I did over the past few weeks to get myself into this jam:
- I noticed the temperature was low (via erics thermometer) when I brewed my first shot in the morning. I initially attributed this to the timer mode and thought I solved it.
- Things were stable for about a week or so. But I had noticed the timer was set far too early in the morning (4 hours before I now make coffee), so I changed it and set it to start later.
- Once the machine has been on for an hour, the grouphead temp was only up to ~125 degrees. After a brief water flush, the machine was up to temp in 15-20 minutes. I was able to retest this during the day, and the grouphead still never got hot enough without that water flush (even after 3 hours it was only at 175). I took the timer out of the equation and began turning the machine on manually.
- I took apart the group (ordered new internals). There was minimal scale on the mushroom but lots on the gicleur screen, figured the scale existed elsewhere. Descaled the machine, 2 hours off, with a dezcal sample I had. I followed a WLL video on YT about descaling the heat exchange boiler, which did not have me overfill the boiler or use a syphon.
- I found scale particles coming out of the hot water wand and steam wand for about 4 new full reservoir tanks
- I read these forums again, found to check the temp probe for scale, and to shine a light into the boiler. It was minor, but there was scale.
- I purchased some food grade citric acid at a local store
- I descaled using the overfill the boiler method and left it to descale for about 4 hours hot with 2 tbsp of citric acid per liter of water.
- Flushing left me with some waste and what I assume is a small piece of teflon tape that came out of the hot water spout

Here's where I think things went really bad:
- I took apart the grouphead, used new parts, cleaned, reassembled again, and problem #2 (8 bars of pressure with no portafilter) and #3 (the backflush problem) began
- I tried descaling a third time (was planning on leaving it overnight), but first put the original parts back in. Started overfilling the boiler. I now believe I forgot to open the hot water wand. This is when problem #1 (the horrible screeching noise) first happened. Not sure what happened if the boiler actually overfilled and where the water would have gone
- I took apart the grouphead, the thermosyphon, the outlet pipe, the four copper pipes that are used to fill the boiler, and the OPV valve. I used a syphon to empty the boiler and the heat exchanger. I soaked all of the pipes and the grouphead itself in citric acid. There was practically no scale anywhere, but figured I'd be safe. After cleaning, I used an air compressor to blow out the inside tubes just in case. I also ran a thin piece of wire in the grouphead.
- I've put it all back together and #2 (it's still at 8 bars of pressure) and #3 (backflushing doesn't discharge) still happens. I haven't tested if problem #1 or #4 exists today.

Since problem #2 and #3 started happening after I took apart the grouphead. I've gone through multiple threads and articles on putting it back together, including the one where erics described spring size, just to make sure I had the right springs in there. I kind of believe I must have screwed this up, as it's the simplest answer.

- I definitely do not have the right "preinfusion spring" (according to erics labels). I'm not sure which of the old springs went in there (there's one spring that seems like it doesn't belong to the normal measurements, but it's thinner and doesn't fit around the spacer). I've ordered new Rocket part numbers for the other 3 springs, but the only one that hasn't come in yet is the preinfusion spring. That's on it's way with the official Rocket green gasket (mushroom o-ring).

Perfectly fine advice could be "put down the wrench and call someone more qualified", but I'd really love to get a win here. Thanks in advance
Mike D | LMWDP #645

decrem (original poster)
Posts: 28
Joined: 5 years ago

#2: Post by decrem (original poster) »

Adding pictures to show more details of the group.

The overall assembly:

The old (original to me) parts are shown for completeness. Included measurements of the springs, both old and new

Close-up of preinfusion spring:

The preinfusion springs don't match, and I'm waiting for one from rocket-espressousa

Close-up of mushroom o-ring:

Two different o-ring sizes from Stefano. Neither matched the green flatter one from rocket. I'm waiting for one from rocket-espressousa

The scale damage to the mushroom was mostly on one side (both pics are same mushroom, just flipped over):

Mike D | LMWDP #645

User avatar
homeburrero
Team HB
Posts: 4863
Joined: 13 years ago

#3: Post by homeburrero »

This is long and multifaceted post, that's probably why no replies yet, but I'll take a whack at it.
decrem wrote:[1] What might this sound be?
I'm thinking it may be related to the boiler fill solenoid. When the boiler is filling it is energized/open and you get noise. When lifting the brew lever that solenoid is closed and quiet. These can be especially loud if some debris is caught in the valve plunger. Solution is to inspect and clean, or replace.
decrem wrote:[2] What might cause this high pressure without the portafilter?
8 bars at the gauge is normal for this machine (that's what I get on my Evo V2.) You have a rotary pump that ramps up very quickly with high flow and the little gicleur in the top of the mushroom is restricting that flow. Of course if you remove the mushroom and gicleur you won't see this back pressure.

decrem wrote:3] If I backflush with a blind filter, the water does not come out of the discharge tube.
That's normal on a rotary. The bypass on a rotary goes from the outlet side back to the inlet side of the pump. The expansion valve feeds into that discharge tube, but if the rotary is set to around 9 bar and the expansion to around 12 bar as is normal on rotary machines you won't see flow out the discharge. ( On a vibe pump machine it's different - on those you set the expansion valve(aka OPV) to allow water out at 9 - 10 bar and you do expect that flow out of the discharge port.)
decrem wrote:[4] the machine takes far too long (hours) to come up to temp.
decrem wrote:Once the machine has been on for an hour, the grouphead temp was only up to ~125 degrees.
Looks like you are seeing a thermosyphon stall. That can be caused by something you did, like leaving the brew lever midway for a while or perhaps doing short flushes. If it happens routinely you may have a leak somewhere (brew valve, expansion valve) in the HX circuit allowing water out and vapor in. See Randy Glass' page: http://www.espressomyespresso.com/stall.html
Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

decrem (original poster)
Posts: 28
Joined: 5 years ago

#4: Post by decrem (original poster) »

This is very helpful, thank you.

Based on what you said, I have ideas on how to approach the thermosyphon stall.
homeburrero wrote: I'm thinking it may be related to the boiler fill solenoid. When the boiler is filling it is energized/open and you get noise. When lifting the brew lever that solenoid is closed and quiet. These can be especially loud if some debris is caught in the valve plunger. Solution is to inspect and clean, or replace.
Can you point out which one is the boiler fill solenoid? I see three solenoids.

A few updates:
- I received the proper preinfusion spring and green o-ring from Rocket. The spring is 43mm -- which is 2mm shorter than the brew spring. The o-ring appears on the surface to be the same as the "thick e61 mushroom o-ring" from Stefano, only it's green instead of black.
- I noticed the preinfusion valve pin I received from Stefano is 1mm larger than the original.
- At this point, I now have only the original metal parts (valves, spacers, etc.) installed with new gaskets and washers.

decrem (original poster)
Posts: 28
Joined: 5 years ago

#5: Post by decrem (original poster) »

I am trying to focus on this problem right now:
[3] If I backflush with a blind filter, the water does not come out of the discharge tube.

After searching more, what I'm experiencing is called a portafilter sneeze. I don't know what the manual 3-way valve is called on an e61, but water isn't coming out of that on a backflush. I'm currently using a garage-sale find La Pavoni Europiccola lever as my backup machine. Removing the portafilter on the Giotto now is exactly like removing the portafilter on the Pavoni if I didn't wait a minute for the pressure to dissipate. pop.

What I notice now is that there's a few mm gap of play between the lever handle and the two hex nuts.


If I push the handle to the left (removing the gap), the cam actually moves into the hole in the group deeper. If there's a gap between the handle, the cam moves out of that hole a little bit. When I remove the mushroom I can see what's going on.


No gap in the lever handle, cam pushed all the way into the pin hole


The gap in the lever handle, the cam has moved out of place

How would I get rid of the cam shaft play, this gap? I believe I have the two hex nuts tightened fully, and the lever handle screw is also tight.

Thanks in advance

decrem (original poster)
Posts: 28
Joined: 5 years ago

#6: Post by decrem (original poster) »

Update again:

After reading these three threads, I'm now assuming problem #3 is a worn preinfusion valve pin:
3-way valve not preventing sneeze
e61 not releasing pressure from cam
help with e61 portafilter sneeze

The new valve that I received came with a 13mm preinfusion valve pin. The original valve has a 12mm preinfusion valve pin.

original valve on top with 12mm pin, new valve on bottom with 13mm pin. Neither of them are working.

The new brew valve that I received has a 12mm pin -- but with different threads, so I can't screw it on to the original preinfusion valve stem. So, to test my theory, I installed the new brew valve where the preinfusion valve would go. I also have the original brew valve in the mushroom. So with two brew valves installed: it works! Water now comes out where it should when I do a backflush. A couple of 12mm pins are now on their way from espressoparts.

Thanks!

User avatar
homeburrero
Team HB
Posts: 4863
Joined: 13 years ago

#7: Post by homeburrero »

decrem wrote:The new valve that I received came with a 13mm preinfusion valve pin. The original valve has a 12mm preinfusion valve pin.
The length of the entire preinfusion valve plus the length of the top part of the exhaust valve are key here.

With respect to lever cam depth, be sure to put it in the right way. The cam needs to be away from the little stop screw you see inside when you put it in, and then you attach the lever so that it's up in the midway position.

Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

User avatar
homeburrero
Team HB
Posts: 4863
Joined: 13 years ago

#8: Post by homeburrero »

decrem wrote: Can you point out which one is the boiler fill solenoid? I see three solenoids.
It's the one by itself over near the pump and expansion valve:



Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

decrem (original poster)
Posts: 28
Joined: 5 years ago

#9: Post by decrem (original poster) »

Thank you again!

Now I have to ask a really dumb question: how do you put the solenoid back together after you take it apart to clean it? I didn't realize there was a spring in it, and it shot up into the air when I unscrewed it.

Is this the right direction? Am I missing any pieces? Thanks!!


The bottom portion is still connected

decrem (original poster)
Posts: 28
Joined: 5 years ago

#10: Post by decrem (original poster) »

For anyone looking at this thread later, I believe this is the answer on how to put it back together:
http://www.espresso-restorations.com/solenoids.html

Post Reply