ECM Giotto Classic - problems with leaking & boiler level

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
7Urban

#1: Post by 7Urban »

Hi,

I recently bought an ECM Giotto Classic from 2000. Machine plumbed to the main water. I have backflushed with machine cleaner. Overall in good condition but I'm having a few problems. Unfortunately there's no service available close to where I live. Can I fix this myself?

1. When steam pressure has built up it starts dripping from the round metal part located center bottom of the front panel (labelled Connector/nr 34 in the parts list). What is the purpose of the connector? The leaking is worse during brewing with water running out of the connector while the pump is active. What could be causing the leak?

2. There's also some dripping from the drain valve, both when the machine is warm and cold. Do I need to replace any gaskets?

3. I can only draw less than half a liter of water from the hot water wand before the pressure drops, boiler is empty and starts filling. It doesn't seem right. Do I need to adjust the boiler level? How?

As far as I can tell the overall function of the Giotto is not affected by these issues. Coffee looks and tastes fine with good crema.


Thanks in advance,
Urban in Sweden

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homeburrero
Team HB

#2: Post by homeburrero »

7Urban wrote:I recently bought an ECM Giotto Classic from 2000. Machine plumbed to the main water.
I think that's an unusual machine, and so you may not see a lot of response on this. All ECM Giottos I've seen are tank versions, don't even have that drain fitting (connector #34) on the front of the machine. Since yours does, I assume it is directly connected to a water main - not just filling a reservoir using a float valve.
7Urban wrote:1. When steam pressure has built up it starts dripping from the round metal part located center bottom of the front panel (labelled Connector/nr 34 in the parts list). What is the purpose of the connector? The leaking is worse during brewing with water running out of the connector while the pump is active. What could be causing the leak?
That connector would connect to tubing from the OPV (aka expansion valve, part #44 in your parts list) in the line between the pump and the HX, allowing the water vented from that valve to go into the drip tray. You can see it diagrammatically in page 3 of this review of a Rocket Evo 2. It's normal that it would drip when the machine heats up - part of the expansion valve's function is to let off pressure in the HX due to thermal expansion. The other thing it does is bleed off water when the shot is finely ground and the pressure from the pump is in excess of 9 bar. So it's normal that it drips more when you are pulling a tight shot. When backflushing, you should see a lot of flow, but when flushing with an empty basket, or pulling a coarsely ground gusher you should see no flow from that connector. The OPV can be adjusted (do a search of this forum for more info about that) and it sometimes sticks open or closed and needs to be replaced.
7Urban wrote:2. There's also some dripping from the drain valve, both when the machine is warm and cold. Do I need to replace any gaskets?
Lots of advice about that on this forum (see, for example Constant dripping from E61 grouphead ) First, do a detergent backflush and see if that helps, but sounds like you probably need to overhaul the group. Check out HB member Randy G's website: http://www.espressomyespresso.com/ - has nice HowTo's on backfushing, cleaning, and overhauling the E61 group.
7Urban wrote:3. I can only draw less than half a liter of water from the hot water wand before the pressure drops, boiler is empty and starts filling. It doesn't seem right. Do I need to adjust the boiler level? How?
You have a less than 2 liter boiler, and a single boiler probe so it's expected that a small draw of water will trigger a refill. I can trigger mine by drawing 150 ml or less. I often draw enough water to trigger a refill just before making a coffee. By starting with a full boiler I don't worry that it might refill in the middle of pulling a shot or steaming the milk.
Changing the boiler level is done by sliding the boiler probe to a different depth. I don't recommend you do that, and it would not change the amount you need to draw to trigger a refill. (If you mess with that probe, note carefully how deeply it is inserted before pushing or pulling on it so you can get it back to where it was.)
Pat
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7Urban (original poster)

#3: Post by 7Urban (original poster) »

Thank's a lot for your reply. I learned a lot from your post! I didn't realize my machine was kinda unusual with its direct water connection. Previous owner was a small shop so that's probably why they didn't choose a tank version.

I should order some replacement parts for the leaking drain valve as I've already tried backflushing with detergent. Gaskets are probably dried up. As for the OPV, I'll search the forum for tips on adjusting. If it needs to be replaced, is it easily done ?

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homeburrero
Team HB

#4: Post by homeburrero »

Is very easily replaced. You may not find an exact replacement. My original valve looked like the one in this pic:
(Picture snagged from post: Considering used ECM Giotto, but needs parts (Sweden))

And although mine worked, it was set at around 12 bar (which is typical) and was stuck tight - could not get the adjuster inside the valve to budge. So I bought a replacement from Stefano's espressocare ( http://espressocare.com/Qstore/Qstore.c ... +OPV+Valve ) that just fits in the machine:


The replacement is an improvement over the original because you can adjust it without disassembling. You probably can find a parts supplier closer to home that sells that same replacement valve. Before ordering make sure of the threading - mine (and the one pictured) have a 1/8" female thread.
Pat
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7Urban (original poster)

#5: Post by 7Urban (original poster) »

My OPV is the same as in that first picture. I'll try and remove it and do a cleaning.
homeburrero wrote:When backflushing, you should see a lot of flow, but when flushing with an empty basket, or pulling a coarsely ground gusher you should see no flow from that connector.
Actually there's no flow from the connector when backflushing, only while pulling shots. Does that imply something else is faulty?

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homeburrero
Team HB

#6: Post by homeburrero »

7Urban wrote:Actually there's no flow from the connector when backflushing, only while pulling shots. Does that imply something else is faulty?
In a quick backflush with the pump on for only a few seconds, you may see no flow - it takes a while, maybe 10 secs, for the pressure to ramp up fully. If you put in a blank and let it run for 20-30 secs then it should start flowing somewhere in the 1 ml/sec to 5 ml/sec range (for an Ulka vibe pump.)
Pat
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7Urban (original poster)

#7: Post by 7Urban (original poster) »

I have removed the OPV. The adjuster inside wasn't stuck and I was able to turn it both clockwise and counter clockwise. I gave it a cleaning and then re-installed it but the problem with leaking from the front connector remained. In fact, it might even have increased.

Even if the adjuster wasn't stuck I guess the OPV can still be in need of replacing. I found a retailer in Sweden who is selling the OPV you mentioned, that allows adjustment of pressure without disassembling. It's quite expensive so I hope that'll do the trick. I was also informed that the solenoid valve can be the cause of the leaking.

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homeburrero
Team HB

#8: Post by homeburrero »

I'm still not exactly clear why you don't think it's flowing as expected.

If it's dripping when the machine is off, and not warming up, then yes, it sounds like it is not sealing properly. Some of them don't seal well if you try to set them low (see Brew pressure profiling with front panel controlled dual OPV)
Note - Unlike a typical reservoir machine, your machine might leak when cold due to a bad OPV -- because there is always a little pressure in there from the water main. BTW, I assume that your line pressure is regulated or is low - especially with a vibe pump it's not good to have much pressure on the inlet side of the pump.


While the machine is heating up it's OK if it drips - as explained earlier, this is venting off the water in the HX and thermosyphon loop that is expanding as it heats up.

The solenoid opens a valve that allows water to flow into the boiler, and it has a check valve between it and the boiler. I don't think that's causing your symptom.

It might be useful to attach a hose to that OPV and run it into a measuring container so you can better describe when and how fast it is flowing out. It might be perfectly normal. Also, while in there, see if there is any tubing other than the OPV outlet that connects to that connector in the front of the machine.

The best test would be to put a pressure gauge on the portafilter and see if you're getting normal brew pressure. If it's flowing out of the OPV and at the same time it never develops 9 or 10 bar against a no-flow portafilter gauge, then you have reason to adjust, repair or replace the OPV.
Pat
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7Urban (original poster)

#9: Post by 7Urban (original poster) »

There's no dripping when machine is off. Only some occasional dripping while it's warm. While pulling a shot the amount of water flowing out of the connector is approximately three times the amount of coffee from the spout. There's no other tubing connected to the front connector other than the OPV.

I did a test and put the OPV at the maximum pressure (center adjustment ring turned max clockwise) and there was no leaking at all from the connector! I then opened it one full turn and leaking started again. Is it a bad idea to have it at max pressure? From what I understand the OPV only determines the maximum pressure but the actual pressure over the puck is determined by dosing, grinding and packing, correct?

Maybe the OPV is working as expected. I was just surprised that it does leak so much, but maybe this isn't a "leak" at all. Don't think I'll be replacing it after all. Maybe a portafilter pressure gauge is money better spent to ensure I don't have too little pressure.

I don't know what line pressure I have.

Thank you for your time and effort to help a newbie.

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homeburrero
Team HB

#10: Post by homeburrero »

7Urban wrote:From what I understand the OPV only determines the maximum pressure but the actual pressure over the puck is determined by dosing, grinding and packing, correct?
Yes, that is correct - the OPV just has to do with the max pressure. If your OPV is set low, or if you are pulling finely ground ristrettos, then the OPV may dictate your brew pressure. Otherwise, brew pressure is a matter of dose, grind, and tamp.
7Urban wrote:Is it a bad idea to have it at max pressure?
Yes, possibly depending on how high that max might be. The OPV is also called an expansion valve, and has an important function in protecting the HX/Thermosyphon system. Since there is no air in that system, and since water is not compressible, it could develop a dangerously high pressure when the water heats up and expands. The OPV/expansion valve relieves that pressure. But there is no problem with having it set pretty high, and they typically come from the factory up in the 12 or 13 bar range, which supposedly works well for ESE pods.
7Urban wrote:While pulling a shot the amount of water flowing out of the connector is approximately three times the amount of coffee from the spout. There's no other tubing connected to the front connector other than the OPV.
That does seem like your OPV may be set too low. If you are pulling a very tight ristretto, getting maybe 15g of coffee in the cup on a 35 second pull, then you would expect to see a lot more flow from the OPV than from your spout. But on a 25 second normale, you should see little or no flow from the OPV.

You can use this chart as a guide: Unreliable Ulka pumps
For an Ulka EX pump, working against a backflush blank, once it gets flowing strong, you would expect roughly 2ml/sec for an OPV set at 12 bar, and roughly 5 ml/sec for one set at 8 bar. There is some variability between individual pumps, and I think in your case it's possible that you would see higher flows because you have some water pressure on the inlet side of the pump.
Pat
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