Odd vibratory pump sound during espresso extraction

[puchang]

Hi everyone,

This has been bothering me for some time. I have an E-61/HX machine with the vibratory pump. I notice that there is always a vibratory sound from the back of the machine during extraction. I know the vibratory pump is loud but I am reluctant to think what happens on my machine is normal. Firstly, there is a brew gauge on my machine and the needle vibrates as well corresponding to the vibratory sound. Secondly, I watched videos of extraction on this site and I am aware that although it is loud, the sound generated by the pump during extraction should be smooth. This is not what I have experienced on my machine. I called the service department of the vendor and they told me my distribution or tamping may be off. I worked on these for a period of time but the vibratory sound is still there. The sound is there no matter I make a double or ristretto so it doesn't seem to have to do with the volume of extraction. Finally, I don't think the vibratory sound has to do with the scale because I had a water-softener in the water reservoir and recently I have been using treated water bought from a local store. I was wondering what could cause the vibratory sound and how to fix it.

This is an extraction video that shows the vibratory sound I am talking about. I think the distribution and extraction, though not perfect, is passable. The shot volume was about 1.5 ounce. I appreciate all your insights and responses. Thanks.



puchang

[oofnik]

Hmm, yeah it does sound just a bit louder than usual I guess. It might be something touching the pump. What kind of machine exactly is it? If I were you I'd open it up and just check to see that there isn't anything touching the pump except the rubber supports and its wires. Otherwise the shot looks good, so it shouldn't be a problem with your technique.

[jesawdy]

I hear some weird rattling sound, but hey, your shot looks great!

Perhaps you should share this video with the vendor if it is still under warranty. With their guidance/advice they may help you sleuth it out.

[HB]

I've heard lots of vibratory pump espresso machines. It may be the recording quality, but based on my experience, the sound wasn't "normal." It sounded more like the rumbling of a boiler heating up than a vibe pump. Does it make the same sound when you run the pump against a blind filter basket? Is the heating element on when this sound occurs? What does the flow from the over-pressure valve return to the tank look like during the shot and against a blind filter basket?

Sorry, I don't have a clue what's making the sound, these are just questions to narrow the possibilities.

[puchang]

Thanks everyone for your responses.

oofnik,

It is a Quickmill Anita.

jesawdy,

I sent another video that records similar vibratory sound to the vendor several months ago. They said I can check if the pump is tightened. I checked and it is tightened.

Dan,

The recording quality is indeed low but I don't think it is the heating element. The sound is there no matter the heating element is on or off. The sound is also there when I run the pump against the blind filter basket. I haven't checked the over-pressure valve return yet but I will take some measurements tomorrow and report back. I set the brew pressure at 9 bars.

puchang

[DaveC]

The recording quality is indeed low but I don't think it is the heating element. The sound is there no matter the heating element is on or off. The sound is also there when I run the pump against the blind filter basket. I haven't checked the over-pressure valve return yet but I will take some measurements tomorrow and report back. I set the brew pressure at 9 bars.
puchang

Im a bit busy at the moment so very quick reply.

1. The sound of the pump and the infusion seems a tad too long, it's remotely possible there is air in the brew circuit (anti backflow valve scaled a little perhaps) a brew circuit descale usually solves this. This could also amplify the sound in 2 (air+water and OPVs can be noisy)

2. The spitting/knocking sound might well be the OPV venting/fluttering as it regulates pressure, especially as the sound only comes on load (so logically it can't be the pump knocking against anything). The anita probably uses the same large OPV as the Andreja, so if it's snapping open and closed you would hear it (big spring inside it).

Also if the OPV is touching the case/frame as well, it would amplify the noise.

P.S. Check the brew pressure as well to ensure the OPV is venting at round 9-10 bar

[Kristi]

as others have said, something is touching the case. open the machine and poke and prod the pump, and the line after the pump, during a pull. Something will alter the sound and that's it. Stuff some foam or something between the pump or the copper tube and the case. Do not wrap the pump entirely in foam as it needs to cool - just between the pump and the case or solenoid or whatever.

[puchang]

1. The sound of the pump and the infusion seems a tad too long, it's remotely possible there is air in the brew circuit (anti backflow valve scaled a little perhaps) a brew circuit descale usually solves this. This could also amplify the sound in 2 (air+water and OPVs can be noisy)

2. The spitting/knocking sound might well be the OPV venting/fluttering as it regulates pressure, especially as the sound only comes on load (so logically it can't be the pump knocking against anything). The anita probably uses the same large OPV as the Andreja, so if it's snapping open and closed you would hear it (big spring inside it).

Also if the OPV is touching the case/frame as well, it would amplify the noise.

P.S. Check the brew pressure as well to ensure the OPV is venting at round 9-10 bar

DaveC,

You might be onto something. I descaled the HX last month and after that the rattling sound seemed to go away for several days and then came back again. I read your article of the OPV last week. I took off the OPV on my machine and gave it a good clean but nothing has changed. Anita and Andreja Premium do have the same OPV and mine looked pretty clean under inspection. You mentioned the anti backflow valve in your post. Can I clean it as well? Is it the copper tube-like thing after the pump? I hope it is not related to scale because I used only treated water as I mentioned in the first post. My tap water is not hard either. Just a little bit more than 3 grains. I suspect my machine should be able to do fine even if fed with water at that level of hardness, right?

Kristi,

I opened up the case, poked the pump and other parts near it this morning. I'm pretty sure it is not the pump because it ran smoothly during the pull. It might be something else but unfortunately I couldn't find the exact location, as everything is around each other and the sound didn't change significantly when I touched anything. I was on a hurry this morning so I will make a more extensive search tomorrow. Hopefully I can find the culprit as soon as possible.

Again, thanks everyone for your responses.

puchang

[DaveC]

DaveC,

You might be onto something. I descaled the HX last month and after that the rattling sound seemed to go away for several days and then came back again. I read your article of the OPV last week. I took off the OPV on my machine and gave it a good clean but nothing has changed. Anita and Andreja Premium do have the same OPV and mine looked pretty clean under inspection. You mentioned the anti backflow valve in your post. Can I clean it as well? Is it the copper tube-like thing after the pump? I hope it is not related to scale because I used only treated water as I mentioned in the first post. My tap water is not hard either. Just a little bit more than 3 grains. I suspect my machine should be able to do fine even if fed with water at that level of hardness, right?
puchang

I dunno what grains are in UK speak. just sometimes these valves get sticky and running a bit of citric acid or similar through them can often clear them out, even if it's not scale, there can be other deposits. if also your are is like the UK, hardness can vary from time to time.

Easy way to check if it's the OPV, close it right up so that the machine is delivering 15 bar (NOT 9 or 10), and pull a shot with some coffee. This will mean that through a normal coffee puck (DONT change the grind), you will still only get whatever pressure your getting (say 10 bar), but the OPV will hopefully NOT try to open, or if it does, may be less inclined to "flutter".

If you do this TEMPORARY check and the noise changes markedly or goes away entirely, then you know the noise is coming from the OPV. Obviously set it back to where it was (you did count the turns)

The decision then is

1. Possibly you may have to live with it (cos it's mainly irritating, but not damaging anything)
2. Find out if air is getting in (descale brew path)
3. If you have an inline softening filter attached to the end of your water pipe (the one that sits in the tank (remove it, I won't go into details, but I hate them), if it's plumbed then don't worry about it.

As a last resort, I guess you could change the OPV (it's unlikely, but mebbe the rubber pad thing has fallen off, or a bit has broken off and your getting the clatter of metal to metal, or there is a high spot somewhere), or a new OPV could just be quieter.

Sorry about rushed reply, but not much time at the moment.

P.S. If you have got air into the system, it can be difficult to dislodge sometimes, running the pump for 20 secs, then off then on for 12 secs then off may gradually move the air out.

[puchang]

Hi DaveC and everyone,

I adjusted the OPV this morning and pulled more than 10 shots. The brew pressure was around 12 bars as I didn't turn the adjustment nut enough to get the OPV entirely closed but the rattling sound was COMPLETELY gone! This makes me believe that the problem has to do with the OPV. But I am still a little bit confused how to fix it. I use store bought RO water now and just descaled the brew path last month so it is less likely a scale problem, although after descaling the sound did disappear for several days. When I disassembled and cleaned the OPV several days ago it surely looked pretty clean. Maybe the rubber pad went bad and I didn't notice it. I may replace the OPV if the problem continues but could it be something else? Thanks very much.

puchang

[hperry]

Hi DaveC and everyone,

I may replace the OPV if the problem continues but could it be something else?

puchang

On the theory that it might simply be faulty, I'd take a shot at replacing it - assuming the part isn't too expensive. The part could be marginal and be affected by relatively small amounts of "crud." If the problem comes back soon after, then you'd have to dig deeper.

[erics]

Puchang -

When you remove the top grill, you'll notice a stiffening bar/resting pad for the top grill at the top of the water tank. Make sure this is tight via the two screws that hold it in place. These screws obviously do not need to be removed for any maintenance.

Remove the outer cover. Check to ensure that the pump discharge hose is not rubbing against the water tank support sheet metal.

Flush about 4 to 6 ounces through the group and feel the temperature of the water flowing in the return line back to the tank - let it run over your fingers - it should be same temperature as the water in the tank. This is normal flow from the deaeration valve attached to the pump. Normal flow from the deaeration valve simply during a flush is about 1-1/2 ounces in 30 seconds. If the water is hot, the OPV is leaking.

Check the strainer at the end of the suction hose, i.e. simply momentarily pinching the pump suction line while flushing will set up a nasty vibration akin to the suction strainer being partially blocked.

The rubber pad you talked about in the OPV should be held in place by a small screw. This is the (i guess you would call it) OPV valve face.

Try to recreate the vibration with the OPV set as it was - be careful not to twist and pinch the lines from the OPV discharge and check to ensure you did not pinch them in your previous adjustments.

How old is Miss Anita?

Eric S.

[DaveC]

Hi DaveC and everyone,

I adjusted the OPV this morning and pulled more than 10 shots. The brew pressure was around 12 bars as I didn't turn the adjustment nut enough to get the OPV entirely closed but the rattling sound was COMPLETELY gone! This makes me believe that the problem has to do with the OPV. But I am still a little bit confused how to fix it. I use store bought RO water now and just descaled the brew path last month so it is less likely a scale problem, although after descaling the sound did disappear for several days. When I disassembled and cleaned the OPV several days ago it surely looked pretty clean. Maybe the rubber pad went bad and I didn't notice it. I may replace the OPV if the problem continues but could it be something else? Thanks very much.

puchang

Well my favourite bet is air in the brew water circuit, this when the OPV is set marginally (e.g. a puck offering similar resistance to the OPV setting). I personally believe this air can cause some "clattering" for obvious reasons, the valve snapping closed much more forcefully when it's letting air out.

The problem is probably not so much dirt in the OPV as air getting into the brew circuit through a leaky anti backflow valve in the pump/brew line somewhere. Replacing the OPV might solve it, but might not.

A $64,000 question for you.........leave the machine switched on for a few hours, don't pull a shot......then with no portafilter loaded, pull a shot while looking at the shower screen. Do you get water pretty much instantly or not?

It might be worth trying a cleaner+descaling product in the brew circuit I think cleancaf is such a product, this might clean out any deposits that are not scale e.g. sludge etc.. (especially with a plumbed in machine you can get other foreign matter in the water).

The last post asked how old was the machine, that would be interesting to know?

[puchang]

How old is Miss Anita?

erics and DavaC,

My Anita is 8 months old. As far as I can remember, the rattling sound started at the second or third month. I will try your suggestions when I come back from the coffeefest in Chicago. Thanks.

puchang

[puchang]

Hi again everyone,

I Cleancaf descaled the heat exchanger of my Anita last weekend in the hope of eliminating the rattling sound. I flushed almost two liters of the descaling solution through the group to ensure the brew path was completely cleaned up. I have been monitoring how it worked out for several days...

Unfortunately the rattling sound is still there...

erics:

I measured the flow of the water back to the tank and I did get 1-1/2 ounces in 30 seconds during a group flush. However, after some idle time the back flow water was very hot during the first few seconds of the flush. I also checked if any hose was rubbing against anything but I didn't find any. How possible is that the OPV is leaking?

DaveC:

I left the machine idle for almost two hours and flushed the group. Yes I did get boiling water pretty much instantly. BTW You mentioned the anti-backflow valve several times before but sorry I wasn't able to find it. I suspect it is the tube-like thing after the pump but I have no idea what to do with it if it has to do with the whole thing. Could you elaborate on that?

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I have noticed that the rattling sound was less prominent or even absent in the first few shots of the day. If I made more than 5 consecutive the rattling sound got more and more serious. Therefore it seems that the pump is not the culprit.

Another HB member PMed me that his Anita also suffered the same problem after several months of purchase. Unfortunately replacing the OPV didn't solve the problem.

I appreciate any thoughts and ideas. Thanks

puchang

[Phaelon56]

A very close friend of mine has the exact same machine - the Anita. He had an identical noise problem to yours beginning from the very first day he began using the machine. Upon investigation he discovered a spot or two inside the back of the machine where a piece of heat resistant foam could be wedged and it reduced the noise to some extent but it's still aggravatingly loud.

He has used my Isomac Tea many times when visiting and there's no question about it - his Anita is much louder than my Isomac and it's a really aggravating noise. When he called the vendor about this they claimed that the Anita is louder than the Isomac Tea because it uses a 50 watt Ulka vibe pump and that the Tea uses a 42 watt. That's a load of BS. I changed the pump on my Isomac once - it is and always was a 50 watt (the vendor in question no longer sells Isomac - I don't know whether the service person was misinformed or if there's some other issue).

It's also worth noting that when he first set the machine up to use it the pump pressure was dialed in way too high - it was maxing out when he tried to pull a shot. He contacted the vendor about it and was given the brush off - was told that his claim simply wasn't possible and couldn't be true. I can state with certainty that it's true and also that the Anita, although it appears to be a well made machine and delivers shots every bit as good as my Isomac Tea, seems to have some inherent noise issue. I don't know if it's a resonance issue with the housing but suspect that such is the case.

We tried pulling some shots with the case removed form the chassis and observed the pump while the shot was being pulled. The pump is sitting securely in the rubber mounts and is not touching any solid objects adjacent to it except for those rubber mounts. Good luck in diagnosing this and please post back if you learn something new - my buddy would love for his machine to be a bit quieter.

[erics]

I measured the flow of the water back to the tank and I did get 1-1/2 ounces in 30 seconds during a group flush. However, after some idle time the back flow water was very hot during the first few seconds of the flush. I also checked if any hose was rubbing against anything but I didn't find any. How possible is that the OPV is leaking?

Seems to me like everything is working normally.

The inlet to the OPV on Anita is tee'ed into the hx outlet piping. The OPV outlet is a short flex hose which, itself, gets tee'ed into a line from the deaeration valve assembly (screwed into the pump) and this all flows back to the onboard water reservoir.

When simply doing a flush (not a backflush) to brusha-brusha the dispersion screen and grouphead undersides, the initial flow of water back to the tank will feel warm because of the hose location and/or if you recently pulled a shot. There will be some flow from the OPV during the course of a "normal" shot and this water is definitely hot.

Back to the noise problem:

On the bottom of Miss Anita, there are three screws you can check for tightness. Two philips head screws fasten the heating element access plate to the bottom of the machine. One M6 hex head screw locates the boiler within the machine itself and thus limits any vibration induced motion. You might check to make sure all three of these fasteners are tight.