Pump stalls under load; bad pump? (Quickmill Anita)

[TimEggers]

Hi guys,

My Quickmill Anita is beginning to exhibit some odd behavior. This morning when running the pump under load (during shot or against the blind basket) the pump literally stops. Goes silent and stops pumping. I notice too the pressure drops a little bit too.

I can then immediately remove the portafilter and activate the pump and it starts right up. Flow seems normal and sounds just fine. I can then make a shot or backflush and all is well until the pump is back under load. Then it stops.

Any ideas what my problem may be?

[cafeIKE]

I'm guessing electrical problem. If there is a bad mechanical connection, when the pump stops vibrating as much at load, the connection becomes intermittent.

Check all crimps and look for any toasted connectors.

This page on the Ulka Pump internals may help. Bon chance.

[jesawdy]

Tim have a gander at the first vibratory pump link in the FAQ and Favorites section... it includes Ian's link above and this little gem too, http://www.myschiffman.org/cg/rebuild.html

YMMV as it sounds slightly different, but my brothers machine did a similar thing (pumped fine under no load and then stalled on load). We disassembled the pump as shown in the link above, cleaned the bits in descale solution and put it all back together with success.

[TimEggers]

Update:

Well its been a month and I thought I had dodged the bullet, but its back to acting up. Previously I had lowered the boiler pressure (for other reasons) and it seems the pump problem went away. Since the problems stopped I kinda forgot about it and wrote it off as a fluke.

Well my luck has run out. Under load the pump stops. I took the panel off and listened to it, as the pump is running and stalls it maintains a hum. I assume its the electrical pump component trying to pump the mechanical parts of the pump. Something tells me I may have a piece of scale.

I did check over every single electrical connection that I could see (even those not related to the pump) and everything is tight and looks shiny and new (no burnt or corroded connectors) from what I could see.

I dread having to remove/disassemble the pump so I opted for a CleanCaf descale/soaking. Its about time for a descale (about 2-3 times a year) and hopefully with a lengthy soak the pump will clear up (wishful thinking most likely).

I'm doing a variant on my Mid-posistion backflush (since CleanCaf is a descale/detergent solution). I then cycle the pump briefly while under load then return to the mid position. I'm hoping this pressurized "scrubbing" will solve my pump issue.

If all else fails I'll remove the pump and do a complete disassemble/clean. I'll try to take photos and document the process and share it here for others to see.

[quar]

If you're maintaining flow and most of your pressure, sounds like you may be having the same issue that erics and I have talked about toward the end of this thread. vibiemme-domobar-super-sudden-pressure-drops-pump-noise-change-during-shots-t7127-60.html

Mike

[TimEggers]

Well no luck.

I called the folks at Chris Coffee with my problem and the very friendly tech walked me through some tests and had a listen to the machine himself via the phone. The conclusion seems to be simple pump failure.

Tonight I've taken the pump out and have completely taken it apart, its as clean as a whistle I don't see any scale on any of it. The springs, valve balls, everything look good. I don't see any obvious blockage or other damage.

I checked every single connection in the whole machine (like you guys and the tech advised) and found nothing loose or the least bit corroded.

Well I'm dropping the bucks on a new pump from Chris and hope this solves my problem. Sadly the pump is barely more than 1.5 years old. Oh well, such is life with home espresso.

[erics]

Tim -

I just want to emphasize what Mike G. posted. In my case, it was the MOST AMAZING event you could wish for. The machine literally went silent except for a slight hum, the pump discharge pressure dropped around 3 bar, the coffee kept flowing. As Anita was typically screeching during a shot, I removed the OPV and did a thorough soaking/cleaning of it in white vinegar for about an hour. My OPV valve face did exhibit the same "seat impression" that was so nicely pictured by Mark H. here:
eliminating-noise-from-vibration-t3268-40.html
I'm now of the belief that BOTH the seat impression and the scale buildup in the OPV contribute to the screeching and that this is somehow connected to the "apparent" pump stall, i.e. I do not believe your pump is bad.

[TimEggers]

The machine literally went silent except for a slight hum, the pump discharge pressure dropped around 3 bar, the coffee kept flowing.

Thank you Eric for the information. One thing though when my pump seemed to cut out the coffee flow would stop almost completely (the pressure would dissipate but once that happened the flow would stop). Seeing that the flow stopped but the machine was still engaged do you think that pump still isn't bad? If not I'll immediately disassemble the OPV. Frankly I'd just like to be back up and running.

Thanks again Eric for the help.

Edit to add: If it makes any difference or not the tech suggested adjusting the OPV to see if it would change anything and it didn't.

[erics]

Tim -

I think its a grey area here and certainly my experience (with Anita) and your situation could be entirely different BUT I do believe its worth an OPV disassembly and cleaning.

Also - if you do order a pump, I would recommend you also buy the OPV rubber insert and OPV o-ring just to have on hand.

[TimEggers]

Thanks Eric, I did just take apart the OPV and it seems fairly clean (like the pump). I am soaking and will clean everything before putting it back. I'm curious are the seats really sensitive to any scale at all, I did see some but not very much at all.

Oh and thanks for the tip on the seat, but is just over a year really that long for the seat?

Edit: Eric good call on the seat, mine is indented too. Funny I thought it was a factory contour for some reason as its so round and seems centered on my seat face. I called Chris and added the seat to my pump order. (I'll just return the pump if I can get the issue resolved).

[erics]

The OPV on Quickmill vibe pump machines is subjected to hx water unlike other machines where the OPV only sees room temp water from the pump. This is certainly a contributor to valve face deformation. The OPV seat is very easy to change (I've changed mine once in 18 months) as is the o-ring that seals the adjustment barrel hex.

I don't believe the valve or valve seat are scale prone because of the relatively high water velocities in that immediate vicinity but the OPV housing and sides of the valve are. I do know that (1) replacing the rubber valve insert and descaling the entire OPV cured the screeching and (2) simply descaling the entire OPV also cured the screeching. I have also (unfortunately?) NOT again experienced that super silent machine operation I spoke to earlier in the thread that Mark referenced.

A test would be to install a new valve insert and reinspect after a month of operation but hey - this takes away from our enjoyment of the machine and its product.

[TimEggers]

I'd like to thank you guys again for all the help.

I think my issues may have been related to what the user was having problems with: http://www.myschiffman.org/cg/rebuild.html

Part #3 seemed like it was jammed too far up against the spring not allowing the valve to open properly. I know this because after my first assembly I had pushed #3 all the way in until it bottomed out which cut all flow from the pump.

So like an idiot (hey this is my first time) I realized what I did so I took #3 back out and just set it inside the brass sleeve assembly and let the fitting that attaches to the pump push part #3 back as I assembled the pump back onto the fitting.

I noticed that the very first time I took the pump apart #3 was really deep, but I didn't think anything of it. Now with it farther out the pump seems to run a little quieter (this may just be my mind playing tricks on me) but it does ramp up much more smoothly. I have yet to see it cut out even once (yesterday it cut out most every time).

I'm going to give it a few days and if the pump keeps running right I won't worry about changing it out. I guess I'll just keep the new pump until I need it.

Really taking the pump out and working on it was pretty simple and now I know a lot more about my machine.

Maybe a silly question but would a boiler setting as high as 1.26-bar contribute to pump failure, am I shortening the life of my pump running this warm?

[cafeIKE]

The difference between 1.2 and 1.5bar is about 7°C inside the boiler.

Assuming that the chassis ventilation reduces the radiated increase, say by 50%, a change of 3 or 4 degrees at the pump is probably not going to significantly change its life.

[TimEggers]

Probably a long shot (and dumb question) but could there be a problem with the thermal sensor circuit? Again I've checked all connections and everything seems ok.

I did put the new pump on because I was sick of the old one cutting out (it did it again this morning). I have a hard enough time making espresso in the morning without wondering if my pump will finish the shot.

Hopefully the new pump will work better, time will tell.

[quar]

Was the flow actually stopping, or was the pump just quiet, as Eric and I have experienced?

Mike

[TimEggers]

The flow almost stopped completely each time the pump would cut out. What frustrated me was that it was always intermittent and only occurred under load. Take the load away and the pump would sound and act fine.

Made no sense to me what so ever.