La Cimbali Junior - Overpressure valve and pump setting

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trusquin
Posts: 4
Joined: 10 years ago

#1: Post by trusquin »

Hi,

I just recently acquired an old Cimbali Junior D/1 with dosing tank. I am trying to figure out few things on this machine (I have owned a Quick Mill Vetrano for almost 10 years, and did some repairs on it).
I am not used to the operation of vibrating pumps, and was wondering if there is any pressure setting ?
Also, there is an overpressure valve (part 537-017-800). I've not looked at the side of it yet, but I suppose that there is a screw to set the max pressure. It doesn't seem that it can be serviced, and trying to find the part online, I only found this : http://www.cafeparts.com/productDetail1 ... emID=67035. It doesn't look like what is in my machine, but maybe it's close enough (and very expensive).

Thanks,

Trusquin.

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boar_d_laze
Posts: 2058
Joined: 17 years ago

#2: Post by boar_d_laze »

Did you try Pasquini in LA?

Rich
Drop a nickel in the pot Joe. Takin' it slow. Waiter, waiter, percolator

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civ
Posts: 1148
Joined: 17 years ago

#3: Post by civ »

trusquin wrote: ... an overpressure valve (part 537-017-800). I've not looked at the side of it yet ...
Disconnect everything and turn the machine so that the left panel is facing you.
Take off the left panel (screws seen through the top panel).

Then you will see that the OVP valve is clearly visible. It has a large slotted screw type head to adjust the valve. (see photo)


Photo courtesy craigcharity

Be careful as this this screwhead has a screw (perpendicular to it, pointing down) used to secure it in place, you will have to loosen it a bit.
trusquin wrote: It doesn't seem that it can be serviced.
No.
The whole assembly can be easily adjusted and if needed, totally dismounted for a thorough cleaning, but that entails removing the top and front panels, maybe even the right panel just to work more comfortably.

Just have to be very careful with the tools used and the torque applied.

Cheers,

CIV

trusquin (original poster)
Posts: 4
Joined: 10 years ago

#4: Post by trusquin (original poster) »

civ,

Thanks a lot, you restoration is an inspiration. I'm not suspecting any issue with the OVP valve yet, but will certainly have to tune the pressure. A two needle gauge like yours should help there.

A while back, I think, you posted a mod to allow for bypassing the dosing probes but you ran into some issues with the Gicar box. Any update ?

Thanks

Trusquin

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civ
Posts: 1148
Joined: 17 years ago

#5: Post by civ »

Good morning:
trusquin wrote: Thanks a lot ...
You're welcome.
trusquin wrote: ... restoration is an inspiration.
An inspiration it is, indeed.

But as much as I would like to have been the author of such a beautifully executed restoration, the photo is not of my D/1. It belongs to craigcharity, I just borrowed the photo.
trusquin wrote: ... not suspecting any issue with the OVP ...
OK, but bear in mind that 'any' restoration process has to have valve cleaning and seal changes.
trusquin wrote: ... will certainly have to tune the pressure.
Right you are.
With the left panel off, it's no big deal.
trusquin wrote: A two needle gauge like yours should help there.
Yes, but provided you have an extra PF and for much less than the cost of that double needle dial (was too expensive at the time for me), I put together one of the many models of pressure measuring portafilters posted here ar HB, most if not all of them, based on Greg Scace's different models of measuring PFs.

After all, once you set the pressure valve, it should (provided grind/dose parameters are in the ballpark) it should not move from the setting. You just check it one a year while cleaning up. But (as always) YMMV.
trusquin wrote: ... mod to allow for bypassing the dosing probes but you ran into some issues with the Gicar box.
Yes.

The idea was to be able to 'push to engage / push to dis-engage' the pump and have greater control over the shot. It worked for a while but then something went amiss and I never found out exactly what. Very relieved after I got it working again, I just decided to use two different dose positions: one for 'short burst' and the other for 'long'.

I use the 'short' as needed to tame the group or do some preinfusion and the long to make the shot, stopping it by moving the switch to the short position. Works OK till I have time to delve in the matter again.

Cheers,

CIV

trusquin (original poster)
Posts: 4
Joined: 10 years ago

#6: Post by trusquin (original poster) »

So, I took the machine apart and started the cleaning. The expansion valve was removed easily. I would like to verify that it's not been altered. Below is a picture :


I did not find an exploded view anywhere, but i'm concerned about the spring. I could replace the whole thing, but I did not find one yet.
This one is pretty close from the look of it :
http://www.cafeparts.com/productDetail1 ... emID=54010

If anyone took one apart, or replaced parts in the valve, could you let me know which one you used ?

Thanks

Trusquin

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civ
Posts: 1148
Joined: 17 years ago

#7: Post by civ »

Hello again:
trusquin wrote: ... expansion valve was removed easily.
See?
Easy enough.
trusquin wrote: ... verify that it's not been altered.
Seems to be complete.
And unaltered.
trusquin wrote: ... concerned about the spring.
Seems to be in good shape.
trusquin wrote: ... could replace the whole thing ...
Why would want to do that?
trusquin wrote: This one is pretty close from the look of it :
http://www.cafeparts.com/productDetail1 ... emID=54010
As you can see from the cross reference table, it is a model (one of many different ones) used in at least three machines.
trusquin wrote: ... replaced parts in the valve, could you let me know which one you used ?
In my experiene/opinion the only part you may have to replace (and after many years of use) would be the rubber stopper.

And something like that can probably be obtained at a hardware store or at a espresso repair dealer.
No big deal.

Cheers,

CIV

trusquin (original poster)
Posts: 4
Joined: 10 years ago

#8: Post by trusquin (original poster) »

Thanks, I'll replace the gasket. A 8x4mm should do it.

Trusquin

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civ
Posts: 1148
Joined: 17 years ago

#9: Post by civ »

trusquin wrote:Thanks ...
You're welcome.
trusquin wrote: ... replace the gasket. A 8x4mm should do it.
Right.
A thorough cleaning of all parts with white vinegar, a light smear of grease to the end of the threads and you're back in (OVP) business.

Cheers,

CIV