Posted Tue Jun 30, 2009, 7:07am Subject: Re: la Pavoni P/TRE - need help to make it work!
benvp Said:
I'm afraid that whatever made the gauge break in the first place could do it again... Could it have been a broken pressure relief valve that broke the gauge?
Posted Fri Jul 3, 2009, 5:55am Subject: Re: la Pavoni P/TRE - need help to make it work!
I've received the new pressure gauge and have placed it in the machine. But of course, as was to be expected, things aren't going very smoothly...
Here's what happening:
The positive: The machine fills up manually (pushing the "push" button), and automatically when the water approaches the minimum level. I then turn the knob into position 2, and the machine heats up. When I turn the hot water knob, hot water flows out. Both the steam and water pressure seem fine, both go up into the green zone when machine has warmed up.
The negative: - No steam, there must be something stuck inside. Inserted a long needle, nothing there, so must be further up. - When I push any button to get water out of the group-heads, the gauge's needle goes all the way to the maximum (less so with the left group than with the right one). - At one point when I was running water through the group there was a loud high pitch sound coming from somewhere... - At some point, water kept going over maximum level by itself when the machine was in position 2 (boiler on), and the red ball that shows the level kept "jumping" up and down...
I have now put some descaling solution through the boiler. I'm now leaving it for a few hours, but the hot water nozzle is letting out very little water... I'm afraid of descaling the HX because of the pressure going so high, I don't want to damage the machine...
Not so sure what to do now... Maybe descaling will solve some of the problems... Otherwise I can wait until I have some time (later this summer), and do a full restauration taking everything apart (but not so sure I'm capable of it...). Or I could get the Pavoni repair-service to have a look at it, but as I'm a student I'm afraid it'll cost me much more than what I can afford...
What should I do...? Any advice? Can I do this myself with some patience? I really like this P/TRE, it'd be fantastic if I could get it to work...!
Posted Fri Jul 3, 2009, 9:54am Subject: Re: la Pavoni P/TRE - need help to make it work!
A quick update:
The descaling hasn't done any (visible) good. When I make water come out of the group-heads, there's a frightening squeaking noise and the pressure still goes straight to maximum level. No steam either.
Any advice would be very welcome! I just have no clue what I should do! And I'm afraid I could damage the machine, or that it could explode in my face!! Cheers!
stefano65 Senior Member Joined: 30 Oct 2004 Posts: 817 Location: Eugene OR Expertise: Professional
Espresso: Vibiemme,Elektra, Grinder: Macap,Cunill, Isomac Vac Pot: not Drip: not Roaster: not
Posted Tue Jul 7, 2009, 5:37am Subject: Re: la Pavoni P/TRE - need help to make it work!
Yes a full rebuild is not a bad Idea BUT don't forget how old is the machine before4 dumping a lot of money into it try to adjust the pump pressure or your PSI inlet from your building perhaps are also too high
Posted Fri Jul 17, 2009, 8:26am Subject: Re: la Pavoni P/TRE - need help to make it work!
Thanks Stefano for you reply.
I've lowered the pump's pressure by turning the screw counterclockwise but it hasn't solved the problem. The inlet line came from a tap in my basement, so I lowered the pressure from the tap too, but it hasn't made a difference either (except lower the pressure before the pump turns on to get water to the groups).
I think the only hope I have is to do a full rebuild. I hope that with patience and reading carefully other rebuild posts I can get through it... :-)
The machine itself (with pump and water softener) cost me 60€, so I still think it's worth a little investment and time.
Any thoughts?
Thanks to all for the help! I'll keep you updated!
procrastinator Senior Member Joined: 5 Jan 2006 Posts: 17 Location: Seattle Expertise: I love coffee
Espresso: La Pavoni P3V2 P/TRE Grinder: Mazzer (Rio) Super Jolly
Posted Thu Jul 23, 2009, 8:16am Subject: Re: la Pavoni P/TRE - need help to make it work!
Hi Ben,
I rebuilt a P/TRE a couple of years back and posted my experiences on the Winter Project posts that you have a link to. I bought my machine for $100 not knowing anything about how to do a rebuild. The project was a lot of fun, I learned how to fix just about anything with the plumbing, and now I have a commercial machine in my kitchen (along with a Mazzer grinder of course)!
I use Caffe Vita beans from Seattle and can make a really great espresso and Americano. I got lessons from some local baristas and was planning to have them over to get their opinions on how to best brew with the P/TRE. Unfortunately my pump or motor has gone out so that visit has been delayed.
I did more of a complete plumbing rebuild. I took the boiler out and soaked it in citric acid. I replaced the boiler gasket (about $25) I removed a good many of the brass tubes and cleaned those, although I didn't find any problems there. I also took apart the group heads and got the insides with a wire brush. I also meticulously cleaned any surface that had accumulated dust or grime. The two little pumps on the back (above where the water flows into the twin heat exchangers) work fine so I didn't mess with them.
The benefit of doing a complete rebuild is high if you intend to use the machine on a regular basis over a long period of time. By doing the rebuild yourself you'll also come to fully understand the machine and be able to diagnose problems in the future. I don't have a manual but I created a block diagram showing all of the plumbing and electrical connections. Let me try to find that and post it here, and it may also be included in my original posts about the rebuild. The diagram will save you a lot of time diagnosing things. There are also a lot of stories and photos posted on these forums and the web regarding other rebuild projects. Espresso machines aren't very complicated and they all work the same basic way so you can learn a lot from other rebuilders' experiences.
My two guiding strategies were: 1) spend as little as possible until I was sure there wasn't some show-stopper problem that would be too expensive to fix, and 2) leave the electronics alone unless I found some unavoidable problem.
Do your research and find web resources that sell parts for the machine. Espresso Parts is a good source, and I recall at least one good resource in Europe. If I can find my old notes I'll post more information.
Regarding the pressure issue, my water pressure is about 5 bar (or whatever the bottom gauge is) coming into the machine, and then when brewing the needle out jump back and forth from 5 to about 9 or 10 as the pump turned. I usually had a squeaking sound when brewing, and just this week either the pump or the motor has quit on me, so I need to detach them and test the motor. Edco in Sacramento, California, sells rebuilt pumps for $45 with exchange.
I'm not sure why the water level is bouncing up and down. When you first turn on the machine you should leave the steam wand open to allow air to bleed from the boiler as it heats up. Wait until steam is hissing from the wand before closing the steam valve, then you'll see the boiler pressure start to build. If you don't do this you'll never get the boiler up to operating pressure (1.1 bar for brewing espresso with this model).
If that doesn't solve your steam/pressure problem, I'd guess you at least will want to take apart and replace the seals on the steam valve. That will enable you to remove the wand from the valve and quickly determine whether an obstruction resides in the wand.
To determine the source of a noise, I found it helpful to use a length of plastic tube like a stethoscope, holding one end to my ear and moving the other around the insides of the machine until I found the precise source of the sound. That's how I diagnosed hissing from a leaky overpressure valve (the big valve on the top of the boiler).
Posted Fri Jul 24, 2009, 6:36am Subject: Re: la Pavoni P/TRE - need help to make it work!
Hey "Procrastinator",
Thanks for your post, it really helps having some feedback from someone who has the exact same machine... Sorry to hear about your pump issues, I hope you'll find a quick/cheap solution!
The fact that you didn't have any experience in rebuilding an espresso machine either gives me hope that I'll be able to do so also!
About the problems I'm experiencing:
HX water pressure. This is my main concern. I'm wondering whether it's definitely the machine that has a problem, or whether it could be the pump. The pump fills the boiler as it should, and the gauge shows a normal water pressure of around 5 bar (after having turned the tap a little, see above post). The problem arises when I push on any button to make coffee: the gauge shows maximum pressure with the needle trembling! The needle goes down to the normal pressure of 5 bar as soon as I stop the water. Plus there's that loud squeaking noise, not very reassuring... I hope soaking all pipes and the group-heads in citric acid, and giving everything a general clean will solve the problem...
Bouncing water level. The steam wand isn't letting out any steam, something must be blocking the flow. I guess that could be causing the problem, as I can't allow air to bleed from the boiler. The rebuild will hopefully solve this issue.
So I'll definitely do a full rebuild. I'm looking forward to taking everything apart, and better understand how the machine functions. It would certainly be useful to have the diagram you made, it'd be great if you could post it. I've read your very informative "winter project" post, and will use it as a guide for my own "summer project".
Thanks for you advice, if you have any more, please do post it!
If anyone has a manual for the Pavoni P/TRE - P3V2, I'd be great if you could post/send it!
procrastinator Senior Member Joined: 5 Jan 2006 Posts: 17 Location: Seattle Expertise: I love coffee
Espresso: La Pavoni P3V2 P/TRE Grinder: Mazzer (Rio) Super Jolly
Posted Mon Jul 27, 2009, 8:57am Subject: Re: la Pavoni P/TRE - need help to make it work!
Hi Ben,
The image size for my diagram is too big to post here, so send me an email address and I'll mail it to you. It's several megs so I may split it into a couple of files.
I removed the pump from the motor and turned on the water flow to one of the group heads, the motor still works. I then tried turning the pump by hand, and it turns. I put them back together and tested, and the pump moves again, although it emits even more of a squeak when it's under pressure. That may be a similar squeak to what you're hearing when you're running water through the group head. The normal water pressure is 5, then when I run water through the group head the needle moves back and forth between 5 and 10. I think this is normal. I only get a squeak when I'm running water through a puck or if I have a blank installed for cleaning the head.
When you say the gauge shows max pressure when brewing, do you mean the needle is going to 10 (the edge of the green zone on the bottom needle on your pressure gauge) or does it go all the way to the max possible on the gauge? If it's only going to 10 I think you're okay. I think the pressure fluctuates as the pump turns, just like a heart beating (and the procon looks like a heart, especially with those two tubes coming out the top!).
Regarding the lack of steam...what is the max pressure your boiler will build up to (the top needle on the gauge)? A local espresso repairman told me that 1.1 bar was the appropriate brew pressure for this machine. You can't get to 1.1 unless you purge air/steam at some point while the boiler is heating up. I'd try letting the boiler heat for 20 minutes before fiddling with the steam knob, then turn the steam knob as far as it will go.
Is the boiler actually heating at all? If it's not then you may have to replace the heating element. Also check the electrical leads to the heating element to make sure they're connected. The first problem I trouble shot with my machine was repairing one of those leads. It's a lot cheaper to do that than replacing the element.
If you're getting boiler heat but you still can't get steam, I suggest rebuilding the steam valve as a first step before you invest in anything else. It seems to me from your descriptions that the machine is generally functioning normally with the exception of the steam problem. If you focus on the things that are inhibiting normal operation, that will give you a chance to make sure the machine is working before tearing everything apart for cleaning.
I have to rebuild my hot water valve, which is the same as the steam valve. It has always leaked and I finally opened it to find a couple of parts and gaskets missing. Espressoparts.com doesn't carry all of the parts I need, so I think I'll order them from coffeeparts.com in Australia. They have a great ecommerce interface with a clear diagram of all the parts and the ability to click on an associated part number to add a part to your order. They add A$20 for international orders, so it might be worthwhile just to pick up a boiler gasket and your grouphead gaskets and screens on the same order. If you happen to get the boiler up to pressure, check and see if the overpressure valve (on the top of the boiler) is hissing. If it is, that means the valve is stuck open. You'll still get the boiler up to pressure but you'll be wasting energy so you need a new one. They're about $25 and that would be something to add to the above order.
Here's a link to the image of the steam/hot water valve:
Here's an idea: you could try switching out the hot water valve in place of the steam valve, just to test whether the valve is the problem (assuming you can get hot water from the valve). You might also do a quick removal of the steam wand from the valve to see if there's a blockage in the wand. When you swap out the steam valve with the hot water valve, take a good-size pipe cleaner and run it through the tube that connects the steam valve to the boiler, just in case there's lime scale build up.
When it comes to taking apart the valve, there are three main parts to the brass casing. Two of the parts screw into either end of the center casing. You'll either need to use adjustable wrenches or buy some big metric sockets for a ratchet. Buying the sockets (maybe $10 each) is far cheaper than buying big metric wrenches ($40 each). Bring the valve casing into your local hardware store to determine which sizes you'll need. If you decide to use an adjustable wrench, use care because brass is a soft metal and you can easily damage it.
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