Replies to This Discussion

Permalink Reply by Wes Russell on January 5, 2010 at 3:30pm

Hi,
That is your thermostat circuit breaker:
http://www.espressoparts.com/MZ_2

It's there to tell you that your brew boiler is to hot and shut it down.

Either it is defective or your thermostat is defective or set too hot.
http://www.espressoparts.com/MZ_260

This could be really hurting your shot quality. I would suggest getting the book:
http://www.espressoparts.com/BOKMZ
since you don't have a tech.
To know the temp of your brew water at the group head, you really need a Scace:

http://www.espressoparts.com/cgi-bin/ep.pl?pgm=co_disp&func=dis...

Knowing the temp will help you dial the temp for the best shot flavor. but if your goal is to stop the breaker from tripping you can turn down the temp on the thermostat. It is located on the top of the boiler and has wires going to the boiler and the the breaker. You can adjust the small screw with a small slotted screw driver. You will want to turn it counter clockwise to reduce the temperature. I would make a note of where it's at in case this isn't the problem so you can return it to its original setting. Just make a half turn and wait five minutes and see if that stops the circuit breaker from tripping.

Since you have more then one shop maybe you can justify the cost as it is nice periodically check and adjust you brew water temp and pressure. Regardless, I would suggest that you a PID upgrade kit:
http://www.espressoparts.com/cgi-bin/ep.pl?pgm=co_disp&func=dis...

This will tell you what your actual boiler temp is and keep very stable. You will also be able to adjust the temp
on the fly and tune the temp for best shot flavor. If your machine is really off and it kinda sounds like it is, this is going to make a huge difference. What this won't tell you is what the actual temp is at your group head. But luckily the offset is pretty standard and you should be able to find that info. I believe for my Linea it was about 6 degrees.
You should let your shot taste determine what temp you should be at in the end so in that way the actual temp is arbitrary.

Hope this helps...

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Permalink Reply by Ross on January 5, 2010 at 5:30pm

What temp are your group heads running at? Those manual reset thermostats are supposed to trip at 250F. So unless your coffee always tastes burnt, I would suggest getting a replacement manual reset thermostat. Espressoparts have them, here is the link

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Permalink Reply by Ross on January 5, 2010 at 6:54pm

For whatever reason, the hyperlink did not work so here is the url - http://www.espressoparts.com/MZ_2

For a small shop to be outlaying serious dollars on Scace devices, PID controllers, etc is a huge drain, so personally I would start by replacing just the manual reset thermostat. Wouldn't hurt to get yourself a copy of the LM Linea "orange book" as well. There is also a LM Technical Manual as well, which I found somewhere in PDF form, so google it & download a copy.

The most important testing device is your tongue, later as you can afford it you can slowly buy other things as your budget permits.

As long as you (or someone at your shop) has some mechanical aptitude, then its all pretty straightforward stuff.

Ross said:

What temp are your group heads running at? Those manual reset thermostats are supposed to trip at 250F. So unless your coffee always tastes burnt, I would suggest getting a replacement manual reset thermostat. Espressoparts have them, here is the link

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Permalink Reply by Marek on January 13, 2010 at 4:20pm

Hi; Good suggestions all, sorry didn't reply sooner... had a most interesting week... kept me away from the computer... good/bad thing... I will be doing some homework related to your suggestions.

A follow up, because we are in Cayman Islands... everything we get ships to Miami. Then we pay additional freight to Cayman and inport duties of 22%... so a $300 item can end up being almost a $1,000... We don't have local tech's ... although... with 300 places to eat... half with espresso machines... ya would think...

Anyway, because of the delay, lack of techs and speed with which we need replacements... we pretty much warehouse spare machines... when something goes down... we swap out. I have a miami supplier who can get a machine on the plane for same day delivery... thank goodness for that...

I really go need to clear my head and consider these excellent suggestions. Some day going to drag a tech down here... we have Fetco 4042 and 2052... Fetco grinders... Mazzers, espresso machines, vita-mix blenders all sitting in the warehouse... enough stuff to open two more shops.

Marek

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Permalink Reply by Jay Caragay on January 13, 2010 at 7:42pm

Marek-
Considering the amount of equipment you have in storage, it's probably worth it for you to fly a tech down there for a week to refurb the equipment - then you'll be good for another three years or so.

Definitely replace that circuit breaker. It usually disintegrates due to age and the heat and is a simple fix.

While the Scace is a great device, it's not really necessary to check the general temperature of the brew water. Simply take a foam cup (6z is ideal), jam a stick thermometer into its side, put the cup up into your grouphead (sans portafilter, of course) and hit the brew switch. Fill the cup and watch the thermometer. That will give you a reading close enough to determine whether or not you are close to your desired brew temperature - and you didn't spend a thousand dollars.

However, if you are hell-bent on spending that thousand dollars, buy me a plane ticket (star alliance, please) and put me up in a hotel for the weekend and I'll bring my test kit along and help you determine what, if any problems, you're facing with your La Marzocco.

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Permalink Reply by Marek on March 16, 2010 at 9:29pm

Hi Wes;

Replaced the circuit breaker and the new one is also popping.

I did the foam cup cheapo temp test at the head and got 190 degrees...

Will try dialing down the boiler a little and see if that works.

Thanks again for all your help and advise.

Marek


Wes Russell said:

Hi,
That is your thermostat circuit breaker: http://www.espressoparts.com/MZ_2
It's there to tell you that your brew boiler is to hot and shut it down.

Either it is defective or your thermostat is defective or set too hot.
http://www.espressoparts.com/MZ_260

This could be really hurting your shot quality. I would suggest getting the book:
http://www.espressoparts.com/BOKMZ
since you don't have a tech.
To know the temp of your brew water at the group head, you really need a Scace:

http://www.espressoparts.com/cgi-bin/ep.pl?pgm=co_disp&func=dis...

Knowing the temp will help you dial the temp for the best shot flavor. but if your goal is to stop the breaker from tripping you can turn down the temp on the thermostat. It is located on the top of the boiler and has wires going to the boiler and the the breaker. You can adjust the small screw with a small slotted screw driver. You will want to turn it counter clockwise to reduce the temperature. I would make a note of where it's at in case this isn't the problem so you can return it to its original setting. Just make a half turn and wait five minutes and see if that stops the circuit breaker from tripping.

Since you have more then one shop maybe you can justify the cost as it is nice periodically check and adjust you brew water temp and pressure. Regardless, I would suggest that you a PID upgrade kit:
http://www.espressoparts.com/cgi-bin/ep.pl?pgm=co_disp&func=dis...

This will tell you what your actual boiler temp is and keep very stable. You will also be able to adjust the temp
on the fly and tune the temp for best shot flavor. If your machine is really off and it kinda sounds like it is, this is going to make a huge difference. What this won't tell you is what the actual temp is at your group head. But luckily the offset is pretty standard and you should be able to find that info. I believe for my Linea it was about 6 degrees.
You should let your shot taste determine what temp you should be at in the end so in that way the actual temp is arbitrary.

Hope this helps...

• ▶ Reply

Permalink Reply by Mike Sabol on March 16, 2010 at 10:49pm

Here are a few more things to check. (Please unplug the machine when doing internal checks like this. Don't get electrocuted.)

Check for loose connections on both sides of the wires going to the breaker. A loose connection can heat up a wire. Make sure to check the connections at the thermostat. Be sure to check the condition of the insulation on the wires and be on the lookout for signs of extreme heating, like discoloration and brittle insulation material. Look at the main terrminal block and make sure it's not cracked and all the wires are in there good and tight. Unplug the machine when you do this.

Check for steam leaks. The pressure gauge and steam valve are right there and steam is hot.

Make sure all the air has been bled from the groups. There is a bleed screw right next to the breaker. It's a 5mm or 6mm allen bolt located in the same place on all the groups. If the machine was not bled when installed, steam, which is hot, can build up in the top of the group. You can not evacuate trapped air by running the group valve because the valve is fed from a fitting further down on the group neck. Unplug the machine but leave the water on and open that bolt a little. Loosen it slowly until you hear air escaping or water starts to seep out. Tighten it back down when water comes out. (Remember to unplug the machine. Very important.) Don't take the bolt out all the way. You'll get a big mess.

Check the resistance on the heating element. If it's starting to loose resistance it will pull more amps. More amps will induce more heat in the wires. (This is a long shot but my time in the field has taught me to always take a resistance reading on elements. It's good information and you never know until you know.)

I bet it's a loose wire or the group isn't bled.

Remember to plug the machine back in! :-)

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Permalink Reply by Marek on March 16, 2010 at 11:15pm

Have printed and will check machine out right now, I happen to live in the same complex as the cafe with the machine giving us problems. It's the only La Marzocco we have, interestingly each shop has a different espresso machine as they were acquired at different times and for different reasons... nightmare for me is equipment failure we have no techs on island and no espresso machines, so four days to a week is best case for me when a machine goes down. I have two, single group 110V, 20amp machines for swapping in... one of those is currently dead... ugh...

Anyway... on the Marzocco... what's likely to be the thing to go... should I consider getting a second pump and keeping it around for ... that day...

Thanks for the very helpful info.

Marek

• ▶ Reply

Permalink Reply by Chris on March 17, 2010 at 2:29pm

Jay Caragay said:

Marek-
buy me a plane ticket (star alliance, please) and put me up in a hotel for the weekend and I'll bring my test kit along and help you determine what, if any problems, you're facing with your La Marzocco.

Ditto for me, I'm available at a moments notice. Of course, I'll bring my Scace, and my Fluke Thermomenter, and the additional pressure kit that I've added to it, no extra charge. Well, you'll have to buy me a coupla beers...

Do one thing real quick, being that you're out there on a sandbar and all, check your power.
What's the voltage? How stable is that? Check voltage between hot legs and ground, just in case...
Know anyone with an oscilloscope?

Ohm's law says that if the voltages are wrong, heaters and motors still work, just slightly differently. Faster, hotter, whatever. OTOH, things at are doing sensitivity testing (amperage, temperature, etc.) may come up with bad answers given bad information.

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Permalink Reply by Wes Russell on March 17, 2010 at 9:13pm

Any luck adjusting the p-stat? This is really the first course of action. Btw, Is the group head sputtering with steam as you run water through it? This also indicates that the brew boiler is running to hot.


Marek said:

Hi Wes;

Replaced the circuit breaker and the new one is also popping.

I did the foam cup cheapo temp test at the head and got 190 degrees...

Will try dialing down the boiler a little and see if that works.

Thanks again for all your help and advise.

Marek


Wes Russell said:

Hi,
That is your thermostat circuit breaker: http://www.espressoparts.com/MZ_2
It's there to tell you that your brew boiler is to hot and shut it down.

Either it is defective or your thermostat is defective or set too hot.
http://www.espressoparts.com/MZ_260

This could be really hurting your shot quality. I would suggest getting the book:
http://www.espressoparts.com/BOKMZ
since you don't have a tech.
To know the temp of your brew water at the group head, you really need a Scace:

http://www.espressoparts.com/cgi-bin/ep.pl?pgm=co_disp&func=dis...

Knowing the temp will help you dial the temp for the best shot flavor. but if your goal is to stop the breaker from tripping you can turn down the temp on the thermostat. It is located on the top of the boiler and has wires going to the boiler and the the breaker. You can adjust the small screw with a small slotted screw driver. You will want to turn it counter clockwise to reduce the temperature. I would make a note of where it's at in case this isn't the problem so you can return it to its original setting. Just make a half turn and wait five minutes and see if that stops the circuit breaker from tripping.

Since you have more then one shop maybe you can justify the cost as it is nice periodically check and adjust you brew water temp and pressure. Regardless, I would suggest that you a PID upgrade kit:
http://www.espressoparts.com/cgi-bin/ep.pl?pgm=co_disp&func=dis...

This will tell you what your actual boiler temp is and keep very stable. You will also be able to adjust the temp
on the fly and tune the temp for best shot flavor. If your machine is really off and it kinda sounds like it is, this is going to make a huge difference. What this won't tell you is what the actual temp is at your group head. But luckily the offset is pretty standard and you should be able to find that info. I believe for my Linea it was about 6 degrees.
You should let your shot taste determine what temp you should be at in the end so in that way the actual temp is arbitrary.

Hope this helps...

• ▶ Reply

Permalink Reply by Marek on March 17, 2010 at 11:09pm

Plot thickens, so printed all the extremely helpful directions here and had a good look at the machine today. Cafe was open so I only eyeballed it... but I think I might see the problem.

The adjustment screw (tiny little sucker) in the middle of the thermostat is MISSING.

So the question becomes, any idea what size that screw is??? I would imagine that the upward/downward adjustment is pushing on an internal relay, so in theory I should be able to get a matching screw.

Indeed, I did the foam cup test and it's running a little hot... so my next course of action would be the screw.

I will also be bleeding the heads in the next couple of days. We're open 6:30AM to 10:00PM and I am in the process of building/finalizing a new cafe downtown so my time is stretched a little thin.

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Permalink Reply by Marek on March 18, 2010 at 11:34pm

eyeballed it... but I think I might see the problem.

The adjustment screw (tiny little sucker) in the middle of the thermostat is MISSING.

So the question becomes, any idea what size that screw is??? I would imagine that the upward/downward adjustment is pushing on an internal relay, so in theory I should be able to get a matching screw.

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