Vibration Pump - Is it worn out

It's often difficult to know if your Vibration pump needs replacing

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had a problem a few weeks ago when i noticed my shots were getting a little erratic and a bit off. I could see on the naked pf that the extractions were getting a bit bubbly and since nothing had changed in my technique i had a look at the pressure. I got out my PF gauge and sure enough it had dropped to about 8 bar. I adjusted my opv up and back to 9 bar. Last week i noticed that the extractions still seem inconsistent (although the pressure was reading 9 bar. i knew I was due a full descale so I put this problem down too a scaly machine and waited for today to do the descale.

I have just finished and have cleaned internal valves (including the opv), they all look nice and spiffy now. Water flow to the GH seems fine and unrestricted….volume of water looks normal through the HX. Put the Portafilter gauge back on but now cannot get more than 8 bar pressure. The opv is operating fine, I can reduce below 8 bar but can go no higher. My thought now is perhaps the pump is failing (it is about 3 years old now?).

My reply

Close the OPV completely, look for no flow and then run the pump against a pressure measuring portafilter, or the gauge and see what pressure you get. If no water is coming out of the OPV tube, cant get more than 8 bar and you (don't have a de aerator), and your boiler pressure isn't rising a lot., then the pump is a safe bet. If water is still gushing out of the OPV, then remove it and try with just the pump and see what pressure you get….then it will be obvious whether it's pump or OPV. 3 years it a little short for the life of the pump, usually it's 5-7 years, but they can go weak in 3. It could also be more scale logged in the pump. color

His next post

Last night the pressure increased to 9bar (but no more) so i have coffee but as we all know unregulated the pump should be pushing out closer to 15bar. I don't believe this is the opv as i have both screwed it right down (effectively bypassing it) and cleaned it so there is no blockages. also the opv operates perfectly just the maximum is 9 bar (now) , after that turning makes no difference. I can happily reduce the pressure with it. The water flow is normal, to my mind a blockage anywhere in the system would reduce flow, not pressure. There are no leaks anywhere. I am leaning towards ordering a pump as i cannot imagine a blockage that would allow normal water flow but be able to hold back 15bar of preasure?

This is typical of Vibration pump failure….under no load e.g. with no portafilter basket full of coffee loaded, they can often produce a normal volume of water, but under load the throughput drops dramatically and often they won't maintain pressure. Sometimes this type of failure is intermittent and the pump is not too bad sometimes, and not so good at others. Also these faults often make themselves more evident after a descale….don't worry the descale is not causing them, but can simply make them more apparent.

The pump, was only 3 years old, so he was a little unlucky….these Vibration pumps can last anything from 5-7 years (depending on use). He was advised to replace the pump, which he did and the problem was resolved for about £25.

The Vibration pumps (image below) are extremely easy to replace, it's a job that takes around 15 minutes. The model shown is a very commonly used pump….the ULKA 48W EX5 and will fit most Espresso machines…don't worry if its a 48W or 52W, EX5 (brass end) or EL5 (plastic end), they will all work. You can often use the 48W Ulka as a replacement for far more powerful Vibration pumps and it's worth checking if it saves a considerable sum of money. Some High capacity/Semi commercial single group machines use 70W Ulka Pumps, but will still work with a fine 48W pump in many cases (as long as the fittings match). Where you might need a specific pumps are with some of the fluid-o-tech vibration pumps which have plug in electric fittings.


A typical Installation in an Espresso Machine:

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