Hi Guys,

I recently purchased a used Faema Compact c-84 fully automatic
machine. It was in great condition when I bought it and I've made some
great espressos with it.


Unfortunately, a problem with the water pressure/flow seems to have
developed: when making an espresso, the flow of water coming out of
the grouphead seems to have diminished, thus espresso shots take too
long to pull. Also, the steam sometimes falters, shooting out water
instead of steam, or a combination of both.


I have, a couple of times, let my water reserve run dry (I am using it
unplumbed, bypassing the water softener) which has perhaps strained
the pump. I have been using filtered water, which I think should be
okay regarding scaling (a Brita filter). Do I need to replace the
pump? Or is it another problem?


I am not super technical, but I don't want to go to my local Faema
dealer, who is purely in the business of extortion.


Thanks for your help.


Nate

<NOTE: crossposted (for the most part) with a private mailing list for Faema Compact owners, however I believe this could be of some interest to the broader community>


I recently had the Ulka vibe pump on my C-85 go out (similar to the C-84, but no flowmeter).
Similar symptoms.

I ordered the Fluid-O-Tech pump from Jason Enterprises - it was around $130, as I recall, and included the opv (which is only there as a safety, not for regulation!)

http://www.faemasource.com/

The same pump is available from Espresso Parts:

http://www.espressoparts.com/W25461

which you can combine with the OPV:
http://www.espressoparts.com/V_873

It is listed as "bypass valve", but it doesn't really function that way. The only reason I have it on my pump is that it came with it, but doesn't seem to be useful for setting the pressure. I used an existing bypass valve (from a friend's machine I'm fixing; mine appears shot in some way).

I also added a http://www.espressoparts.com/W_635

which is the connector that mates with the pump; According to Fluid-O-Tech's documentation, you need to put a diode in-line with the pump. I wired up a 3A Radio-Shack rectifier diode, fit inside the connector.

It really changes the sound of the pump; the old one went "nom nom nom nommmmmm nommmmmmmmm nommmmmmmmmmm" and would stall out with a backflush. The new one just rattles and buzzes.

You can hear the old pump here:
http://www.youtube.com/watch?v=nKIE61K6TFI and
http://www.youtube.com/watch?v=aZR28jQUN3A
and the new one here:
http://www.youtube.com/watch?v=W8inWa16mVQ&t=153s

If you want me to get some pictures of the new one, I can, though it's a bit kludged in there; I couldn't get the "bypass valve" off of the pump, so I couldn't get the rubber mounting bracket on properly. So it's kind of hanging from rubber bands, with a rag stuffed in to keep it from banging against the sides of the machine and transmitting its vibrations more efficiently.

It's a long way for water to travel in this machine before it gets to the pump so if you are drawing water using the braided supply line and have not removed or bypassed the inboard softener then I wiould say you are asking too much of the old and possibly tired ulka pump. The softener canister may be allowing air to enter around the top cap which would also cause a pressure loss.
I recommend plumbing in if possible (regulate the input pressure to 15-30psi) and bypassing the filter canister all together. If you choose to replace the pump the FoT 1106 is a good option and will work with the existing OPV. The bypass is not required if using the original OPV but as previously posted you will need the wiring cap and diode.
BTW Brita filters will remove setiment but they do not soften water or prevent scale.

Allon -

You're confusing THERMAL diode with an ELECTRICAL diode. I agree F-O-T's documentation is confusing but what they are referencing in their illustrations is a THERMAL diode, i.e. Klixon thermal "fuse". The FOT pumps and the Ulka pumps all contain an internal diode which knocks out half of the sine wave.

The OPV which, most times, comes fitted on the FOT pump is just fine as far as I'm concerned - perfectly suited to the pump's flow characteristics.

erics wrote:Allon - You're confusing THERMAL diode with an ELECTRICAL diode. I agree F-O-T's documentation is confusing but what they are referencing in their illustrations is a THERMAL diode, i.e. Klixon thermal "fuse". The FOT pumps and the Ulka pumps all contain an internal diode which knocks out half of the sine wave.

References, please?

From the F-o-T manual:


From the Espresso Parts webpage http://www.espressoparts.com/W_635

When used on a Fluid-o-Tech vibratory pump, there is a small diode inside the connector: FR306 DC or FR307 on terminals 2 and 3

FR306 and FR307 are fast recovery rectifier diodes (though fast recovery makes little sense in this application).

http://parts.digikey.com/1/parts/416012 ... 306-t.html


According to all information I've found thus far, there is an electrical diode to go in the circuit.

Sorry - I stand corrected - much thanks.

I just took two connectors apart and there were the diodes FOT specs out. Pump works fine with the diode (obviously) and not so fine without.