Noisy/faulty OPV and use of OPV in general - Page 2

[dsc]

Hi everyone,

I've reread Jims post and I agree with him fully. It's what I had in mind when I was writing my description, but I made it a bit confusing through incorrect usage of pump/output flow.

As for the change in voltage I haven't noticed anything like that on my machine, but it does make sense, my apologies for stating that the pump is only frequency dependent (of course to a certain level).

I will try to upload a video of the pulsating action going on during the extraction. Eric can you describe where the bleeding valve is usually installed? I understand it is being used to get rid of any air in the tubes/installation?

Here's how the inside looks like, although it might be hard to see the details:







Cheers,
dsc.

[erics]

You have it - it is the brass valve screwed into the snout of the CEME pump. The discharge from this valve is tee'ed into the output of the OPV and then back to the tank.

[dsc]

Hi Eric,

thanks for your help, you are indeed a walking/living/posting coffee machine encyclopedia:)

I will disassemble it today and try to check what's going on. I will also try to disassemble the pump, although I'm pretty sure it's not going to be easy (or doable at all).

Cheers,
dsc.

[erics]

No, this forum is the encyclopedia - we all learn from each other.

Why disassemble the pump?

Go to the CEME site I referenced earlier and test your pump flow with an empty PF into a measuring beaker. TYPICAL pump discharge pressure when doing this is around 4.0 Bar, depending on the gicleur installed (typically 0.70 mm). Time the volume as a "delta" from, say, the 200 ml mark to the 600 ml mark or whatever graduations are convenient. Do this with the heating element disabled and convert everything to liters per unit time and compare to the value shown on the CEME site for your discharge pressure and your pump.

Write the results down in the owners manual and date it.

[dsc]

Hi Eric,

I wanted to disassemble the pump just out of curiosity, to look inside and maybe lubricate it as it's a bit loud (I know all vibe pumps are, but it still sounds louder than the pump on my old Gaggia).

Will do the measurements tomorrow, however I know that the typical pressure with the PF locked in the group is 4 bars and I believe the gicleur is 0.7mm.

Cheers,
dsc.

[erics]

Well, if you remove the pump, you can get two points "on the curve" by simply running the pump (mounted on a piece of wood) and measuring the performance at zilch discharge pressure.

You will also get a good feeling for the pump noise when mounted outside of the machine enclosure.

I do not believe these pumps are lubricated with anything other than water. For sure, excess clearance (if any) between the plunger and the barrel will produce more noise but then maybe its time for a new pump or a CEME rebuild kit if one exists.

[dsc]

Hi,

yesterday I disassembled the bleeder valve and most of the things attached to it. I also unscrewed the cup connecting the brew pressure gauge and found some scale build up inside the tube to which it was connected. Decided to remove the whole part of the installation between the boiler, OPV and the tee to which the gauge is connected. Soaked that and the end of the pressure gauge tube in citric acid and put it back together. I also shortened that white plastic tube that goes from the pump into the solenoid valve, because it was pushing the pump against the case. Now it's all a bit more quiet and the flow pulsates less, so I guess it had something to do with the bleeder valve.

As for the pump it looks like this and I can see no way of disassembling it:



I made some measurements today, although with the heater element still connected. I got pretty close to the characteristic on CEMEs page, so I guess the pump works pretty well.

Cheers,
dsc.

[CambodianBeast]

Sorry to bump an old post, but I am having very similar issues, and was wondering if the steps described here helped solve the pulsatile brew problem.

My Anita has been squealing for some time now, but until today I had not noted any pulsatile component to the water flow or pump sound. This AM I noted both - the pump noise is pulsatile in nature, alternating between slightly higher and lower pitch at a rate of ~3Hz (3 pulses/second). The flow of water out of the grouphead was also fluctuating slightly, although the brew pressure gauge was steady at 9 bars throughout the extraction and the resulting shot was fairly good.

I'll start by examining the bleeder valve this weekend - any other suggestions?

Thanks,

D

[erics]

D -

Order a replacement valve insert (or two) for the OPV and replacement o-rings for the adjusting screw from Chris' Coffee and disassemble/clean OPV in some white vinegar for about an hour. Lube new o-ring with food-safe grease.

See here: help-needed-how-to-change-seat-of-expansion-valve-on-andreja-premium-t8155.html

Adjust your OPV to 9.0 bar with a blind basket and you should be fine. This will fix the squealing and MAY fix the pressure pulsation.