The machine will show the error message “Ground too fine adjust mill” when it senses it is struggling to push the water through the coffee system. In most cases, you will come to a point that drawing water will not clear the error but only reset it for another failed attempt at making espresso.
Can’t clear this message or it is happening more frequently now?
Let me help you understand what is happening when this appears, and what steps and repairs you can take to resolve the error. First, you can check out the video we made on this very problem below:
If you dont want to warch the video, you can continue to read through the article to solve your issue.
To fix this error, you adjust your grind courser and “Insert Water Spout and Press OK” to draw water through the system, putting water through the system resets this error.
Here is why this error shows itself. Your Delonghi machine measures the water going through the system with a flowmeter.
When the Flowmeter or Turbine senses the water isn’t flowing or is struggling to move through the system your machine goes into error. “Ground too fine adjust mill”.
There are a lot of components that can be blocked or can fail that affect the water flow through the system. Before we start on diagnostic and servicing parts the very first action you need to take is to descale your machine.
This is important, you should be descaling your machine no longer than every 3 months intervals and more frequently in hard water areas. It can be costly to ignore the descale light.
Think of it as an oil change for your machine, and if you ignore this it will likely require parts to be replaced. So, avoid some extra cost in parts and service and descale your machine, it needs to be done.
The proper Delonghi Descale can be found cheap on Amazon, and here’s our own tutorial for how to properly descale your machine. Use the brand descale as it offers the best result for your machine, and absolutely DO NOT use vinegar.
After a good descale, next up is to try to figure out specifically why the error is happening. Delonghi has several components that can be the cause of this error:
There are a few more parts to the water system that we won’t talk about as they won’t cause this error, such as Steamer, Solenoid valve/Steam valve, and the coupling that connects the milk carafe option.
Now that we have that out of the way we can move on to the good stuff. In all my experience this error is usually a result of neglecting the service of your machine. Here are possible causes in order of the flow of water.
A lot of the information on the web will lead you to believe the Turbine / Flowmeter as the issue Link Part 5213225251 But I need to tell you It has been very rare that this part has failed.
Important – please read on.
The job of the Turbine is to measure the flow of water going through the system, what happens is the turbine does its job properly but if you have a blockage somewhere else in the water system the Turbine reports to the machine there isn’t sufficient water flow. The turbine didn’t fail, it has done its job, what it was designed to do.
There have been very few reasons the turbine will fail, these are the main two I see.
This small filter is designed to catch large debris/coffee ground that could possibly work its way into the water system. It isn’t the common cause of the famous “ground too fine adjust mill”, but it can and has happened. Here’s a replacement filter on Amazon if you need to replace it.
Next in the system will be the pump. There is a quick way I check to see if the pump is functioning properly. With the panels of the machine removed, I will take the hose off the water outside of the pump and turn the machine on to see if water starts to flow. Be ready to turn the machine off as you only want to see the pump is functional. The water will not be hot as it hasn’t reached the Generator to heat it up at this point. If you get flow this is good news, we can move on to the next part to inspect.
There is usually a date on the pump and if you are getting on to 8+ years old it can be a good idea to replace it. The pump is inexpensive and very easy to replace.
I have seen pumps last 3 years to 13+ years with a well-cared-for machine.
You can have a pump fail or you can have the pump wear out and underperform. I suggest you replace the pump outright and not try to rebuild it. You will see some information on how to take the pump apart and reassemble but unless you have the very specific O-rings and sphere you will be just reassembling a pump that didn’t perform in the first place. The pump can wear out because it has run its lifetime, or it has been stressed because of blockage in the water system over time. There is a small plastic sphere in the pump that will eventually wear out as the water is constantly passing it as it vibrates in the pump.
One more note: If you use an oily bean in your Delonghi you can shorten the lifetime of the pump. I don’t want to tell you not to use an oily bean, but it will cause stress in the system as it takes more effort to produce your espresso. A nice dry bean works great! Amazon.com : Lavazza Super Crema Whole Bean Coffee Blend, Medium Espresso Roast, 2.2 Pound (Pack of 1) : Roasted Coffee Beans : Grocery & Gourmet Food
The valve is connected to the outlet side of the pump and can look different on varying models of Delonghi. This part usually doesn’t fail, but again, I have seen this fail once or twice, so I think it is notable. Other than a visual check (explained below) you shouldn’t spend much time focusing on this part.
Test 1- with the back panel off, initiate a brew or hot water, if possible, if the water leaves the valve through the overpressure hose then it is possible the valve has failed.
Test 2 – disconnect the hose between the generator and pump and again initiate a brew or hot water. What you are looking for is water to come out of the pump/valve.
Be ready to unplug the machine you only need to know the water is passing through and don’t need to let the water flow after you confirm. If you have water, move on to the next possible issue
I have to say it again, try a descale before you start taking the generator apart.
This is the usual suspect when you get the message, “grounds too fine adjust mill” Delonghi uses two scenarios to heat and move the heated water through the system to give you espresso.
The older first models of the ESAM machines would be the reason why. The Delonghi Generator is a one-piece unit that heats the water, directs the water, and tamps the coffee. There are several things to go wrong with this part, although it is a higher-priced part you can think of it as the engine of your machine. I usually replace the complete unit when I confirm it to be blocked. But let’s do some diagnostic.
There are several different Generators and Mechanics valves that look the same so be aware you will need to know the right one for your machine. Call Delonghi or a retail store selling these parts to ensure you have the right one. They can check for you.
The ECAM version is the newer version and Delonghi has separated the boiler from this component.
Usually called the Mechanics valve. This unit can fail in mostly the same way by being plugged to the point of non-functional. Scale is a common issue in these components, and it can become completely clogged. Some machines don’t descale this part during the descaling procedure.
The infuser can be problematic when it isn’t taken care of. A few notable issues that cause the most grief:
There are mainly two infusers used in the Delonghi machines and usually inexpensive to replace.
With the old version of the ESAM, the infuser installation is done by opening the front door of the machine. Here is a replacement part found on Amazon.
ECAM, The newer style of infuser installation takes place through the right side of the machine behind the water. The version of the part can also be found on Amazon.
To sum it up those are the reasons why the “Grind too fine adjust mill”. Try and find where the blocking is taking place. Before you take it all apart try and descale the machine and clean and lubricate the infuser/ diffuser, then try your diagnostic.
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I’m the Coffee Grump. I’m a tech guy, not a sales guy. I love coffee, and I service the equipment that grinds and brews it for you. I have more than 25 years of experience in technical and customer service in coffee machinery, and I hope to share some of that experience with you with this website!
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