Rocket Appartamento - Possible Pump Issue

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by Brent1975 »


I was making an espresso yesterday with my usual weight of beans and the same grinder settings I've used for ages and my machine choked. After cleaning the grinder, I had the same issue this morning and eventually had to move my Kinu from 0-9-0 to 1-1-0 to get back to my normal output in my usual time.

The flowrate out of the group head is 480ml/min and backflushing seem normal; the mushroom was also spotless and I couldn't see any issues with piping in the machine when I removed the side panels. I'm also having a lot less issues now with channeling!

Wondering if anyone has encountered this and whether the culprit was their pump?

Finally, how easy is it to replace the pump in an Appartamento, as it doesn't look particularly accessible?

Any thoughts or feedback would be greatly appreciated.


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#2: Post by cafeIKE »

What is the coffee roast, roast date and storage method?

Over night seems strange, but coffee does age and minor dose / grind adjustments are normal

Did the weather suddenly change?

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Brent1975 (original poster)

#3: Post by Brent1975 (original poster) »

It's Italian dark roast coffee stores in an airtight container. I normally have to make minor changes to the grinder as the coffee ages, but this was an overnight change of 10 ten times what I normally make. Which makes me think there might be a problem somewhere.

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#4: Post by cafeIKE »

Do you use the Kinu only for espresso or other prep methods as well?

How do you measure the dose?
Verified after grinding?

Does the machine have a pressure gauge?

please update your profile as it helps to know what you're using


#5: Post by JRising »

Quite possibly the pump getting weak... Especially if the machine is 7 or more years old.

If you run the pump with the brew valve closed, do you hear the pump run and stall, or does it happily run over the expansion valve? I know the Appartamento doesn't have a pressure gauge, but when running like this with the valve closed, how strong is the flow over the OPV/Expansion valve? How strong does the pump sound? (The further they get from full stroke, the quieter/duller they get).

And if you determine that the pump is at fault, no worry. Changing a pump is easy. Just be really careful not to cross thread the bubbler valve in the new pump.

Brent1975 (original poster)

#6: Post by Brent1975 (original poster) »

I only grind with the Kinu and weigh my coffee before and after (scale is accurate to 0,01 grams). The pump sounds the same when in brew mode and when back flushing. The machine is also only just over two years old. I will buy a group head pressure gauge, but my suspicion is that the factory setting was way too high and it has now dropped to something more reasonable, but the drop in pressure is a sign something is amiss.

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#7: Post by cafeIKE »

Can you see what model the pump is?
According to Chris Coffee it's a 52w pump, which should flow more than 450mL

The drop in pressure could be caused by a bit of grit in the OPV which finally worked free... or a failed o-ring

Appartamento Hydraulic parts / pump area