Nuova Simonelli Mac 2000 Issues

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

#1: Post by Waazupdoc »

Reaching out to all out there who are familiar with Mac 2000. I was careful to take multiple pictures while i descaled the entire machine. Have owned it for almost 20 years and was able to trace my problems down to needing to be heavily descaled but also I am having an issue with the Pressure and Heating element chip on the main board. I have a new chip I will be resoldering hopefully next week. But the one picture I did not take is of course the problem i am having now :( I am losing water through the piece circled in Red in the picture. I don't remember the piece circled in Green. I am thinking while I disassembled that piece I must have had a piece that rolled off the bench or tossed accidently. It just leaks water enough to not build pressure in the machine. Does anyone know if there is a spring or something else that I am missing? I have looked through all forums and all Nuova Simonelli literature to find this exact area and am unable to find any spring it looks like its just 3 pieces 1/4 nut, cork and copper washer.

Thanks to everyone for the help.


#2: Post by Tj. »

Hello. Can you update your post with the photos? They don't seem to be visible as is.

Update: I see it now. The boiler drain plug seems like a strange place to be unexpectedly loosing water. I'm unsure if there is supposed to be a rubber oring or spring off the top of my head. I can confirm in a few days when I am back with my Mac.

Waazupdoc (original poster)

#3: Post by Waazupdoc (original poster) »

Thanks I appreciate it

Waazupdoc (original poster)

#4: Post by Waazupdoc (original poster) »

TJ were you able to identify if i may be missing something?



#5: Post by WWWired »

Hi Waazupdoc :) The Nuova Simonelli Mac models are truly beautiful espresso machines with genius engineering and design that have formed the foundations for nearly every current day high quality espresso machine.

Great post with fantastic photos to assist all future readers seeking information :) Interestingly, you appear to have caught a rare typo in the Nuova Simonelli Parts Diagrams for the Mac 2000 model number for part 07300100, a 3/8" to 1/4" reduction fitting (its instead labeled as an Expansion/non-return Valve, 98003018).

It is assumed this is a Nuova Simonelli Mac 2000 V model (as compared to the 2000 S) based on the partial photo of the Control Unit. The location where a flow meter is usually located is not shown in the photo so its difficult to be sure 100%.

Short Answer: No, it does not look like you are missing any parts. As there is water in this part of the Steam Boiler's Hydraulic pathway at all times (or at least there should be), this drain cap that is leaking may be not sealing or screwed on to the fitting completely. It may be worth disassembling the fitting and Terminal Cap assembly that is leaking (17mm wrenches) to see if it is all clean or needs a good citric acid spa day for all of those components. Here's a photo of what one looks like disassembled . . .

The components circled in thin green line in the third photograph (of the original posters pictures) appears to show the schematic for an Expansion Valve Assembly (Part 72012007) attached to the Drain Tub/Cup for Group 2, 3 and 4 machines. It appears the Mac 2000 in the photos is a single Group machine and thus the Expansion Valve Assembly may not be attached to the Drain Tub (Part 05000016). The Retaining (non-return) valve in your photo three (circled in thin green) is shown in that photo as in the Group 2, 3 and 4 machines, but in the single Group it is attached at the back of the boiler to the fitting that may be either an L (Model S) or T (flow-metered model V) fitting threaded into the 2-way Solenoid's Body inlet port (usually labeled 1 on the top of it). The side that is labelled 2 is the outlet port. Water flows from 1 through the 2-way Solenoid to the outlet port, labelled 2, and then to the fill port for the Steam Boiler. In the Mac 2000 S model this is the simple case, but in the Mac 2000 V model, the water line T-Fitting after the Retaining Valve (non-return fill valve) goes in two directions with one direction going through a flow meter and the other direction to the 2-way Solenoid as mention above.

Side Note (likely not an issue with the drain cap leak here): Here's a video showing the Retaining (non-return/check) Valve, on the right in the video, that is usually attached to a fitting between the 2-way Solenoid and Flow Meter in a Nuova Simonelli Mac 2000 V model . . .
NOTE: Take great care when unscrewing the small center piston pin that holds the rubber gasket in place as the threads can be corroded and forcing it may shear the screw leading to a need to replace the piston assembly. The second thing to note in the video is that while these gaskets can be quite chewed up, in the video it is shown that the gasket may be possible to just flip over and get a fresh sealing face. In the video the gasket was just replaced as one was on hand but in a pinch (when the Expansion/non-return valve is not preventing backflow), the gasket could be flipped over and checked to see if a good surface is available for use while waiting for a replacement gasket to arrive.

Likewise, photograph three's (of the original poster's pictures) diagrammatic red thin line circling is likely associated with Group 2, 3 and 4 models of the Mac 2000. More importantly, the item labelled 98003018 may perhaps be somehow incorrectly numbered in the schematic shown; it might possibly be part number 07300100, a 3/8th" to 1/4" reducer-connector-fitting. In a single Group Mac 2000, this reducer fitting does not connect exactly the same way as in Group 2, 3 and 4 machines, and instead is the terminal end of a pipe that T's (at a brazed/solder T-tube-fitting) at the bottom of the Steam Boiler, with the other branch connecting to the 2-way solenoid's fitting at the back of the machine.
Waazupdoc wrote:. . . I am losing water through the piece circled in Red in the picture. I don't remember the piece circled in Green. I am thinking while I disassembled that piece I must have had a piece that rolled off the bench or tossed accidently. It just leaks water enough to not build pressure in the machine.
As mentioned above, the "Cap" (see attached photo below), Nuova Simonelli part number 07300063, is part of a terminal stop for a drain. The source for any water flowing from this "Cap"/Terminal-Stop-plug could be the thin-gauge copper tubing that comes off the outflow port of the 2-way Solenoid at back of the Steam Boiler/machine. As such, it is basically a boiler drain plug. You can see in the photos below there are no check valves or springs in the reduction terminal end fitting that goes into the drain cup mentioned as leaking. It may be that the screwed on cap is not tight enough or the cap has some mineral scale or other debris on it. It is a compression fitting that forms a seal on the two metal surfaces (one the "Cap", Part No. 07300063, and the second the chamfered inner 30° surface of the "Reducer Connector" fitting, part number 07300100), and the "Connector" (Part Number 07300009) is a compression nut to tighten the mating surfaces onto each other.

Waazupdoc (original poster)

#6: Post by Waazupdoc (original poster) »

WWWired Thanks so much that was a very detailed response much appreciated. I am starting to form another random issue. I believe my main board has a faulty chip. It wasn't heating up and when I messed with the board it started working then randomly shut off again.
I was able to get another chip from Mouser ... cyCode=USD I soldered it in place but now the heating element kicks on and will not shut off and the pressure keeps building but nothing reads pressure on the gauge :roll: so now I'm trying to figure that out. Does anyone have any ideas? Was it the wrong chip? Maybe it's a very specific one and I need to get another board or it's related to something else.

Waazupdoc (original poster)

#7: Post by Waazupdoc (original poster) »

I resoldered the old chip back in and still having the problem with the heating element not shutting down when it reaches temp and no pressure is showing on the gauge.


#8: Post by WWWired »

According to the Nuova Simonelli electrical schematics for the 2000 V model, this may be the pin layout. Any confirmations or corrections from experience much welcomed . . .

User avatar
BaristaBoy E61

#9: Post by BaristaBoy E61 »

Just thinking out loud, so please forgive the randomness of my thoughts.

The 1st thing I'd do would be to install a fresh 9v battery in your DMM, the lo-batt indicator is lit. I know it might not change anything - but...

I doubt any chip or microprocessor is the problem. Have you verified the AC voltage output & continuity of the PWR XFMR primary & secondary windings? Fuses look OK.

Do you have 12vdc output from the power supply? Is the power supply filter cap OK?

What is the resistance to ground of the water level probe (you can pull the connector from the probe if you like)?

I would suspect a defective pressure stat or (temperature) probe.

Can you post a complete electronic schematic of the machine?
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

Waazupdoc (original poster)

#10: Post by Waazupdoc (original poster) »

Simply put... WOW. Okay so think all is good now I had a few issues but think I have a functioning machine again. I resoldered the back of the board and thew it back in. Once installed of course I verified all voltages and it everything was checking out. I had about 20ohms on the element when filled and no bleed over to ground. There were 2 things I believe that were giving me problems. The water level probe in my video was down further then the temperature stat causing it to keep heating for a period of time longer then usual. Once I twisted the water level prob to the left or right to bring the water level above the temperature stat the heating element finally would shut off at the correct temperature. The reason the pressure on the gauge was not working is because the winding in the gauge itself was stuck with gunk. Once I cleared the debris it started to function as designed. Thank you all for your help with this it certainly was a head scratcher but it seems to be working well now. I think some fine tuning and it will be even better but at least I can have some decent coffee now :D