Nuova Simonelli Premier Restoration Part 2

The hydraulic line was generally intact and without evidence of any prior leaks. However, it was the sight glass assembly that captured my attention, even when I first inspected this machine. The sight glass displays how much water is in the boiler. This is especially important because it can diagnose many problems if the water is not around the middle of the gauge. If the gauge is full of water there will be no room inside the boiler to make adequate steam, and the water level probe needs attention. If there is no water in the sight-glass, unless the lower pipe is blocked, there is no water in the boiler. Running a boiler element dry could lead to the heating element failing and the machine itself to implode from its own expanding gravitational pull. This picture is the fitting to the boiler that the lower sight glass pipe connects with the sight glass assembly.
Maybe some readers will look at this mysterious crud without much of a nod, but I kid you not it gave me nightmares. Specifically, I was scared that the inside of the boiler was coated in such a crust, also that the hours of chipping and soaking in acid would eventually dissolve both this substance and the magical cure for cancer contained inside it. The lower sight glass pipe accompanied the machine, unattached. I believe it was initially removed to drain the boiler before the whole thing was discarded. It would be just another part to be cleaned and inspected for damage. I would not be able to feed water into this machine until this was repaired.

Another part that would no doubt need replacing is the dual pressure gauge. The gauge has two inputs in the back, one on top and the other below. The top gauge connects to the top of the boiler and registers how much pressure is in the boiler. This is quite useful because steam pressure also reflects the internal temperature. While other methods are much more accurate, boiler pressure will also give a temperature guess for the brew water. The steam pressure gauge will also express when the pressure is sufficient to use the steam wand or hot water spigot. As can be seen, the green space starts at 1 and the red starts at 1.5 which is common to all espresso machines I have ever worked with. The bottom gauge is attached to the water main just after the pump and reads the water pressure. The green zone is between 5 and 10 bars of pressure. Typically, the water pressure feeding the machine is under 5 bars and the pump will bring that pressure up to around 9 bars during the brewing process. As you can see, the water pressure gauge is stuck at approximately 18 bar. Maybe if I throw it against a wall it will work again, probably not though. As they cost around $100 it will be a part I replace once I decide to either sell the machine or put it into production. However, just reading a post on lethargic pressure gauges, I might just soak it in acid and see if anything changes.

Disassembling the hydraulic lines was swift and generally unphotographed, sigh. I think my general sorrow of the upkeep and my fear of running out of latex gloves before everything found its way into the acid. Taking off the drain cup and expansion valve were quick to remove as was the boiler-fill electro-valve and hot water spigot valve. Starting in that order, the drain cup is where all the extra and dirty water pools before draining out of the machine. The expansion valve does just as its name implies, gives the water in the hydraulic system space to expand as it heats. The electro-valve lets water pass through the valve by electric command of the control board. The black box is fastened around a hollow cylinder that contains a magnetically controlled plunger. I was much more hesitant taking it apart than putting it back together. It is quite a simple yet effective device. The valve for the hot water spigot did not want to release its design secrets as willingly. Other than the handle, not one part of it was willing to unfasten to my herculean efforts. Since the valve seems to move fluidly I am not too afraid of it being clogged. I will test it out once everything is put back together to see if it leaks. After that it was just carefully removing all the copper lines. Hoping that part diagrams and a logical understanding of the system, only one picture was taken. Oh goodness, I hope this will not be a mistake.

Nuova Simonelli Premier Restoration Part 1

I have always loved tinkering around with projects. This is my first major rebuild.

I was not given much information about this machine other than it had not been working for many years and it was recovered from the recycling bin at a major hotel. I took a quick look-see at the boiler and the main water/steam lines to see if there were any apparent faults. It looked as good as I could expect for the price, so it came home with me like a puppy.

There was no plug for this machine so I never got to test it out before starting to strip it down. The lower fitting to the sight glass was missing so there would be no way to fill the machine with water to see if there were any major leaks either. My plan was to start taking this machine apart with a part diagram and note anything that was missing or broken. From there, soak everything copper/brass in citric acid to remove any scale, test all the wires for continuity and start re-assembly with whatever new parts necessary to test the major parts/functions of the machine. As paint is quite inexpensive, I would also repaint the base since I would not want to dismantle this machine again to properly paint the base if it was not a lost cause. I hoped to be able to bring this machine to testing quality before buying any big ticket items such as new panels that are more cosmetic than immediately functional.

Once the panels came off, it was easy to start identifying parts and possible problem areas. Everything was horrifically dirty with smells of old coffee, older milk residue and newer leftovers of some sort of rodent. It was remarkably easy to remove the touchpad and enclosure.

From there I could easily get to the groups, steam wand and hot water valves. All seemed to look good and move around easily. I was quite certain that I would need new gaskets for many of these parts but the parts seemed to be in good condition. I would only know once I scraped off the accumulate milk. No picture would do proper justice. Thankfully the group heads, while caked in old coffee and grime, did not have any significant wear. Only small parts were missing from the groups such as one diffuser and a shower screen. As expected, the group gaskets were as hard as the metal they fit into.

Starting at the start of the hydraulic line, I took out the pump to see if it would turn with the force of my fingers. I know that these are not very cheap. Thankfully it turned with only a little effort. While inspecting the T fitting that leads from the pump to both a flexible line that feeds the rest of the machine and a small brass tube that goes to the water pressure gauge, it has a gicleur in it!

Note: A gicleur, also known as a flow restrictor, is similar to a metal nut with out the head and a small hole through the length. These are screwed into a fitting in the water's path. Generally, it restricts the flow of water. This part was not in the schematic and I was surprised to see that there would be a pressure regulator this early in the path. When I checked the download fittings after the flowmeters there were no gicleurs on either of them. I am assuming that it was put here to avoid the cost of two $2 gicleurs further down stream. Even the people at ECM were a little surprised. I am disappointed to say that in my haste to clean this part from the scale that had built up, I completely stripped the gicleur with my alan key excitement. The part is unknown and reportedly unavailable, so I will be replacing this part with the descirbed parts on the part diagram by putting in two new gicleurs after each of the flowmeters. If nothing else this will make the machine a little more consistent with modern machines coming out of the Simonelli factories. For semi-automatic machines, the dosing buttons on the front portion out a specific amount of water for a shot. This event starts the pump to feed water to the group head through the flowmeters, one for each group. Inside the flowmeter are magnets on an impeller which spins with the flowing water, providing an electrical signal to the computer how much water has passed.

Since it was starting at me in the face all the while, I took out the brass drain cup. I tucked it away under a stack of shop towels so I would not have to look at it before I could clean it up and soak it in citric acid. It was so filthy then and knew that it would look much better after the cleaning.