Pasquini Livia 90 - Meltdown

Postby Tio Tom on Mon Apr 22, 2013 9:11 pm

I purchased a Pasquini Livia 90 that suffered a major 'meltdown.' The guy I bought it from was not the owner at the time of the problem so he didn't have any details. I am including some pics to show the condition of the machine. The heating element burned through the casing. I am not sure what the two white 'block' shaped electrical components are but I believe they are supposed to prevent overheating, but one is totally fried. I saw a parts diagram which shows a larger over-temp thermostat device attached to the center of the bottom cover of the boiler but my unit did not have anything like it when I got it and there doesn't appear to be any wiring for it. Does the Livia 90 have a history of over heating? My serial number is LA004396605. The machine is in excellent condition cosmetically and I want to get it in action. Looks like the boiler got so hot it cooked the pump as it swelled up on the side nearest the boiler.

Image
Image
Image

Thanks for any suggestions, observations, etc.

Tom B.
Tio Tom
 
Posts: 8
Joined: Jan 09, 2012
Location: Hialeah, Florida

Postby cannonfodder on Tue Apr 23, 2013 10:50 pm

That is bad. Heating elements blow now and then but the most common cause is an empty boiler and someone turned it on. The question on that one, is the fried electronics a side effect of the element blowing or the cause.
Dave Stephens
User avatar
cannonfodder
Team HB
 
Posts: 7865
Joined: May 23, 2005
Location: Downingtown PA
www.espressoparts.com: espresso machines, grinders, brewing equipment & parts
www.espressoparts.com: espresso machines, grinders, brewing equipment & parts

Postby Tio Tom on Tue Apr 23, 2013 11:34 pm

I found out that the component is a capacitor. I saw a wiring harness with the same capacitor for older models and the description says it is to prevent overheating. However, I think the damage to one on my machine was caused by the massive overheating of the boiler. I tend to agree with you that the heating element burned up because of a empty boiler, but what I cannot figure out is why it would stay on with no water. The Livia has two water level probes which leads me to think that maybe the processor or another component is defective since the system should have shut down power to the heating element. The third picture shows the plastic cover which attaches to the bottom of the frame and covers the boiler. I it maybe an inch from the boiler itself so it took some heat to burn the hole in it. Thanks for your interest. TB
Tio Tom
 
Posts: 8
Joined: Jan 09, 2012
Location: Hialeah, Florida

Postby jontyc on Thu Apr 25, 2013 9:31 am

The white plastic boxes appear to be RC snubbers (capacitor and resistor) used to iron out transients on the relay's coil and switching sides.

My first (inexperienced) thought is that the capacitor in the RC snubber on the switching side of the heating relay has failed shorted, meaning the heating relay is bypassed.

Its remaining 100 Ohm resistor can't handle the resulting current (he needs his capacitor) so he melts his white housing. If this resistor also failed shorted, the heating element would be constantly on.

Assuming water in the boiler, the pressure would build but the pstat ignored because it only controls the heating relay (which is bypassed). The safety valve would kick, in releasing steam reducing the water level in the boiler. The boiler low probe would be ignored (which also controls the heating relay), boiler dries out, melts bottom cover and element eventually blows.
jontyc
 
Posts: 32
Joined: Feb 06, 2013
Location: Australia

Postby Tio Tom on Mon Apr 29, 2013 9:59 am

Image

Jontyc: Thank you very much for your reply. Your explanation sounds very plausible and it has put my 'non-tech' brain to work big time. I would be very interested in your comments on the following:

I tested the 'fried' capacitor/resistor with a multimeter and it does not appear to be shorted in the closed position. I am including an additional photo which seems to show that the melt-down of the component is external rather than internal.

Be that as it may, if the shorted out capacitor/resistor did bypass the switching relay and directly feed the heating element, can its wire size on it handle the load of 1200 watts for the element for the time required to boil out all the water? Buy the way, the boiler pressure gauge was permanently pegged at the maximum setting of 2.5 bar. At this point I am trying to figure out a way to test the setting on the relief valve, but nothing as of yet.

Finally, is the function of the capacitor/resistor it is to prevent overheating of the element? I have found a replacement and it is sold as a part of an 'add on' harness for older machines to protect the element.

I have located and purchased all the replacement parts to put my machine back together and obviously I don't want to see first-hand a repeat of the melt-down. I sincerely appreciate your interest and expertise. Thanks again. TB
Tio Tom
 
Posts: 8
Joined: Jan 09, 2012
Location: Hialeah, Florida

Postby jontyc on Mon Apr 29, 2013 11:21 pm

Yes looking at the new picture it does appear to be damaged from the outside and although I can't get a real feel for the wire size from the photo, yes, probably not able to handle the 11A that would be flowing.

But that's all moot given it appears to be melted from the outside.

The capacitor/resistor network is often placed across the output of relays to stop arcing and premature burnout of the contacts, and across the inputs of the relay to stop reverse voltages from the collapsing field through the coil going back into the driving circuit.

So I'm not sure how the capacitor/resistor is preventing overheating as advertised. I'd be interested to know if these two white boxes are indeed across the inputs and outputs of the relay as I'm just assuming.
jontyc
 
Posts: 32
Joined: Feb 06, 2013
Location: Australia

Postby kize on Tue Apr 30, 2013 6:07 pm

Many years ago I owned an older Livia 90. There was an "upgrade" kit that came out for the older machines after they were sold. One of the parts in the kit is the one you are holding. From what I understand and remember, the pressure stat on the older machines was originally wired directly to the heating element. The contacts would sometimes fail and cause a runaway pressure stat thus a constant on heating element. The kit was a rewire description (no Pic or diagram), that sealed (melted piece you have) and some wires and terminals. I believe the kit was to move the element load to a relay contact already in the machine and use the pressure stat to control the relay and reduce contact arcing. If you contact Pasquini- I'm sure they would have more info for you and possibly provide you with a wiring diagram. I know I would like to have one given the shoes you are in. Keep in mind that was quite awhile ago and my memory isn't as hot as it used to be.
kize
 
Posts: 179
Joined: Jun 09, 2011
Location: Washington

Postby jontyc on Wed May 01, 2013 12:56 am

Maybe a story is emerging here with Kize's info. The previous owner bought the upgrade kit but didn't secure it well and one of the white boxes ended up touching the boiler?

From what I've read, the Livia 90 is a rebadged BZ99. Here's the wiring diagram for the BZ99, showing the RC networks across the relay inputs and outputs. You can see the heating element requires the pressostat to be closed, plus the GICAR control box to be happy. Experimenting in the past, I've found the GICAR to be happy when the water levels both in the boiler and tank are not low.

Additionally you can can see the heater element won't heat if the thermostat says it's too hot, but you don't appear to have this safety thermostat.
jontyc
 
Posts: 32
Joined: Feb 06, 2013
Location: Australia

Postby Tio Tom on Thu May 16, 2013 10:46 pm

I now have all my replacement parts and almost have the machine assembled. All the comments that have been posted are much appreciated and needless to say I have learned a lot. I confirmed with a Pasquini technician that the two RC components are original equipment on my machine. Also, I forgot to mention that my machine is an automatic so the diagram for the BZ99 does not show the flow-meter and push buttons. However, I am thinking that the wiring between the Gicar controller and the relay would be the same. I am debating about replacing the relay since it does show some signs of arcing. As soon as I have some results of my first attempt to start it up I will post them. Thanks again.
Tio Tom
 
Posts: 8
Joined: Jan 09, 2012
Location: Hialeah, Florida

Postby Tio Tom on Tue Dec 03, 2013 6:29 pm

I apologize for my delay. The machine is up and running. I replaced the pump, heating element, safety relay, and burned up capacitor along with the group since it was originally set up for ESE pods. (Wife sold ESE group w/portafilter on Ebay which paid for new group!) I received some expert assistance from Mike at Pasquini in LA to reconnect the relay and when I plugged it in SUCCESS! :D I still do not know for sure what was the cause of the original 'melt down.' When I cleaned everything and put it on line, the level control worked fine so your guess is as good as mine on the original problem.

There is one small 'glitch' that I haven't been able to eliminate. At times, when I turn the machine on, it starts pumping water out the group. I first thought that maybe the boiler fill valve was sticking so I cleaned it thoroughly but problem didn't stop. Maybe a 'brain' problem with controller but I am hoping not. Along the way found a Moka grinder on Craigslist at a good price and a two-drawer base on Ebay. I am happy with the performance of the machine for its size, it makes a good coffee and has plenty of steam. I did install a smaller two-hole tip. I loaned the entire set-up to some friends and after a few days they were sending me photos of their latte creations. Made everything worthwhile. Will post photos later.
Tio Tom
 
Posts: 8
Joined: Jan 09, 2012
Location: Hialeah, Florida