bloodtypelatte Senior Member Joined: 20 May 2007 Posts: 19 Location: Batavia, NY Expertise: I live coffee
Espresso: Nuova Simonelli Premier Maxi Grinder: Nuova Simonelli MDX
Posted Fri Feb 29, 2008, 1:20pm Subject: Help w/ Nuova Simonelli Premier (Backflushing boiler/low pressure/underextract)
If opening this be prepared for a long read. I post in this forum today, as I am in need of some help, desperate help. I appreciate and thank in advance anyone who helps solve my machines problems or steers me in the right direction.
Where to start...
We can start with a bit of background I suppose. I work for a local coffeeshop in Upstate NY. We brew with our Nuova Simonelli Premier Maxi and use a NS Premier MDX grinder. The machine needs some TLC, and when I say TLC, I mean in desperate need of some TLC. The owner is far from an espresso connoisseur, he knows little to nothing about espresso. (He doesn't clean the machine, doesn't train his employees, leaves tons of preground espresso to rot in the grinder, and gave me a blank stare when I asked for him to toss me the tamper the other day). However, unenlightened he may be, he is good hearted; cheap but, good hearted. The espresso we serve is rancid, underextracted, water (not that anyone would even realize it with the sugar in their latte). I recently brought this to his attention and that we should clean the machine, investigate the problems it has, and fix them promptly. He is fine with what I do to help the business and espresso quality but, has a 'if they don't know it's broken why bother fixing it' type of attitude. So... anything that is done is with my own time, effort, and money. Ie. I work about 20 hours a week at the shop, as coffee is my passion, and most of my check goes straight back into the machine (tamps, dispersion screens, pitchers, brushes, books, etc are all bought by me). So that being said I'd like to fix things myself (good hands on experience), keep the total bill relatively low, and in the end just be able to go to the shop and have a good ristretto from time to time.
I have already posted once with problems and haven't really gotten anywhere with a solution. I will start with what I have already troubleshot (past tense?).
- COFFEE: all good, fresh, locally roasted cofffee. Used within a week of being roasted. The espresso blend is also very nice and not the root of the problem (the roaster makes a mean shot with the same beans and a different machine).
- GRINDER: It isn't the highest quality grinder out there but, is a decent grinder with adjustable settings. I clean it ever so often to get rid of the rancid oils. It does need new burrs though....
- GRIND: This is a possible problem but, unlikely. I cycled through almost the entire range of settings on the grinder the other day but, still failed to create a good double.
- DOSING & TAMPING: I use between 12-15g of espresso for a double shot. And tamping is fine. 30-40lbs initial tamp, tap side twice to set espresso along sides of PF, polish top with a twist of tamp. Espresso is evenly packed and does not come into contact with the dispersion screen. PF is dry and cleaned prior to shot. ~~~ I occassionaly use a naked PF to keep my tamping in check and I get a nice cone from the bottom, a blonde underextraction ridden cone but, a cone non-the-less.~~~
- WATER TEMPERATURE: No problems here. 92-96 celsius always. Water temp is always constant and I always flush/purge the group to stop flash steaming and bring the temperature down prior to pulling a shot. I also always start a shot immediately after purging overheated water.
- WATER HARDNESS: I can only imagine the last time (if ever) the water softener/filter was changed. The boiler has never been emptied, de-scaled, cared for... ever. I would like to do this even if it may not solve all or any of the problems with the machine. But, I find it hard to belive that 3 years of scale and calcium build up contribute nothing to my dilemma. To check out the water situation, I purged some water into a cup and let it cool the other day. I tasted it and it tasted alright but, not clean. Something is in the water I just don't know what... ~~~ Every other day I back flush the machine with a blind filter and machine cleaner but, it doesn't seem to help anything out at all.~~~
- BOILER WATER PRESSURE: This is a major problem. I dont know what is wrong but, pressure is way low. It brews at about 4-5 bars according to the guage on the machine. I checked the gaskets in the group and they are abit older but, are still holding a good seal. The pressure stays constant throughout the shot at 4-5 bars. Also, after brewing/ backflushing the machine a find it impossbile to get the 3 way solenoid valve to trigger after the a stop the brew cycle. Even, after backflushing the machine (5 seconds on, 10 seconds off up to 10 times) I see nothing shoot out of the valve into the tray. I also notice a bad PF upchuck/burp (I think that is the term) after I remove the PF from the group (even after waiting 20-30 seconds). Does this mean I would have to make adjustments to the valve's release pressure?
- EXRACTION: Dosing & timing seems right. See action 5 seconds from start of cycle and end up with close to 2 ounces of espresso in the end. However, the espresso looks underextracted and light the whole time it is brewing and is completely blond by about 15 seconds into the shot. The resulting shot is very bitter tasting with little to no crema at all. Underextraction.... I blame this on pressure but, am not completely sure. I've taken into account just about every variable I could think of or read about. Someone help me. Please. Does anyone own this machine, used it, know how to fix it, can tell me how to fix it, know a friend who could tell me how to fix it, know a book that would help me fix it, travel to Batavia, NY for free to fix it :-D. Let me know. And thanks in advance.
GabrielB Senior Member Joined: 27 Mar 2007 Posts: 226 Location: Chicago Expertise: I live coffee
Espresso: Maver Junior (HX), Silvia... Grinder: Wega Max (K6), Rocky Vac Pot: Bialetti Moka & Brikka Pot
Posted Mon Mar 3, 2008, 12:36pm Subject: Re: Help w/ Nuova Simonelli Premier (Backflushing boiler/low pressure/underextra
I thought someone would snag this one and give some feedback. I don't own a commercial system, so I don't know if I can offer any useful advice.
The pressure stays constant throughout the shot at 4-5 bars. Also, after brewing/ backflushing the machine a find it impossbile to get the 3 way solenoid valve to trigger after the a stop the brew cycle. Even, after backflushing the machine (5 seconds on, 10 seconds off up to 10 times) I see nothing shoot out of the valve into the tray. I also notice a bad PF upchuck/burp (I think that is the term) after I remove the PF from the group (even after waiting 20-30 seconds). Does this mean I would have to make adjustments to the valve's release pressure?
I'd say this is a good place to start investigating. 4-5 bars does not sound normal for brew pressure. Also very odd that the three way solenoid valve doesn't do anything, even when backflushing. Do you see the brew pressure increase when backflushing? The manual recommends 30 seconds on, rather than 5 seconds. Not sure if this would make a difference. Issues could be that the valve body is stuck (limescale, etc.) or the coil has gone bad.
I'm including the above link for reference, not to necessarily tear down the machine and have you guys close shop for 2 weeks. It gives some pointers as to what may be causing problems with the 3 way solenoid valve.
I can only imagine the last time (if ever) the water softener/filter was changed. The boiler has never been emptied, de-scaled, cared for... ever. I would like to do this even if it may not solve all or any of the problems with the machine.
The manual also covers how to re-charge the water softener. Regarding descaling this machine, I wouldn't know where to start on a commercial unit. I had recently tore down my home machine and used citric acid (food safe), which did an awesome job. Maybe someone who works with professional machines can chime in on this one.
BrainstormPrintCafe Senior Member Joined: 28 Mar 2008 Posts: 1 Location: Douglasville, GA Expertise: Pro Barista
Posted Fri Mar 28, 2008, 8:39am Subject: Re: Help w/ Nuova Simonelli Premier
I have a Prem. Maxi system as well and it needs a lot of TLC
Now, we have a pressure problem as well. The machine registers 4/5 constant bars of pressure, and what was explained to me was that the Volumetric pump that regulates the pressure in th emachine is no longer functioning. The pressure that is in the machine is slightly above the water pressure going into th emachine.
I know that in my area, EspressoSouthEAst.com is a distributor and repair service for these machines. You might want to find a local service to you and see about getting your machine fully checked out.
burnt Senior Member Joined: 29 Jan 2008 Posts: 21 Location: Las Vegas, NV Expertise: I love coffee
Posted Fri Mar 28, 2008, 10:05am Subject: Re: Help w/ Nuova Simonelli Premier
This is what I would do...one day when the cafe is closed or one night or whatever, I would pull off that 3 way valve. It's giving you trouble already, so it's worth pulling apart, clean it in citric acid, just to make sure it's working correctly. Also, your backflushes probably don't do much without this valve working correctly...it will also be a good indicator of scaling and buildup in your machine.
Once you do that, as you have time, pull off a valve or piece of piping (the materials reference above are very comprehensive) and see if there's scaling/buildup in any of the piping. I think your lack of pressure (shouldn't it be 9 bar?) is the reason you have bad coffee.
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