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LR pump sounds different when lever engaged

Hello guys and girls,

I have found in the past and I'm finding again now that the rotary pump sometimes makes a different, unhealthy, sort of sound when lever is engaged.
Tank is always full and well fitted in place, no water filter installed so it's never a case of pump running dry and always fed bottled water.
When I draw water through hot water pump and the pump activates, it sounds pretty normal. At least to my ears. When I draw water through the group, the pump will either make a higher pitched sound or as of 2 days ago a weird rattling sound. Nothing in machine position has changed so it's not a case of piping in contact with anything. I flushed a full tank's worth in stages to see if it would alleviate the symptoms and at the end it seemed to subside but it was apparent again this morning. This occurred both when running digital PI at 3 bar and at 4.5 bar.
Videos of the sounds can be seen on the two links.
Do you think it's something in the solenoid? I had meticulously cleaned it out when I first got machine a year ago when debri was blocking flow so not sure if it's a similar fix.
Hot water pump activation


Group lever pump activation


Also on a second note, when idling (sometimes, not always) I'll get that mini pump activation every 20ish minutes even at sub 4bar pressure. No stream leaks that I can see. Is that normal or do I need to tighten nut under rotary as discussed in previous post? At high PI bar 5 and above the pump definitely acts strange. Will try and get a video of that at some point.

Thank you
BW
Christos

Comments

  • hi christos

    you open with 'I have found in the past and I'm finding again now'

    how did you fix it last time?

    kind regards

    reiss.
  • next: i dont see or hear anything abnormal in either of the videos

    in the first video where the boiler is being refilled you have the pump coming back on intermittently after the boiler has filled

    i expect this is the result of the expansion valve being set too low

    could you please tell me the maximum pressure displayed on the pressure transducer console after boiler has filled - it should be about 11.5 bar

    kind regards

    reiss.
  • Thanks as always for quick reply Reiss!
    So the pump on lever pull always has a different tone to when boiler is refilling but for weeks it will sound abnormally high pitched and then it will return to normal. This past week it's instead been making a rattling sound as though it's vibrating against metal/plastic. Hard to hear on video but I've now Dropbox linked a sound file where you can clearly hear it change from rattling to what I'd consider normal halfway through (at around 6s). This was a lever pull with no portafilter and with digital PI set to 3.5.

    https://www.dropbox.com/s/7zupjvm932lbep3/LR pump.m4a?dl=0

    Now onto next bit, I didn't have too long before work this morning but I've attached a vid of the digital PI reading when idle just after hearing cycle and then when hot water is drawn. With bar set to 4.5 it will drop to 3.8 during refill and will peak at 8.9.


    As for lever pull without portafilter and digital PI set to 4.5, bar drops to 0.4 and peaks at 9.4.



    When I find time I'll make a clip of how the pump reacts at higher PIs of 5 and above as it seems to run for a longer time than at lower PI (expected) but puck soaking is much slower (unexpected). Doesn't really reach the point where it does the stuttering sound suggesting that it's reached max bar. Perhaps it's to do with the little screw under pump needing adjustment.

    Sorry for long winded response, hope it makes sense.

    BW
    Christos
  • hi christos

    first issue:

    quote:

    Hard to hear on video but I've now Dropbox linked a sound file where you can clearly hear it change from rattling to what I'd consider normal halfway through (at around 6s). This was a lever pull with no portafilter and with digital PI set to 3.5.

    www.dropbox.com/s/7zupjvm932lbep3/LR%20pump.m4a?dl=0


    i have turned the sound volume up to max on my laptop and listened to the above audio file: there is nothing abnormal about that sound given that it is through the heat exchanger and to accentuate it further the portafilter is removed. the reason for the difference in sound relative to the sound when the boiler is refilling is one of back pressure/restriction. When the boiler is refilling the pump is under load, having to drive water through the relatively small aperture of the inlet solenoid. Conversely, when the lever is pulled down there is almost no flow restriction in the heat exchanger circuit and therefore the pump is not under any load to speak of and therefore it becomes more high pitched. Doing this with the portafilter removed actuates this behaviour even further

    When your pump has a problem you will have no water delivery and will hear a faint electrical hum as the vane has seized in the pump liner and the motor is unable to turn the pump so the motor hums

    You do not have an issue with your machine

    kind regards

    reiss.
  • second issue:

    if the pump pressure delivery screw on the pump was set at a pressure less than the target pressure you had set at the pressure transducer the pump will simply run forever

    as far i can tell from the video clips provided this is not occurring so therefore i do not recommend you touch the pressure adjustment screw for the pump

    the pump blipping on signals that pressure is being lost from the system and the pump is being called to restore the target pressure

    kind regards

    reiss.
  • third issue:

    after a boiler refill in particular you can hear the pump chopping in repeatedly to lift the pressure in the circuit

    it is pronounced because cold water has been drawn into the pre-infusion circuit up to the inlet solenoid which is closed after filling

    the hot system then quickly heats the cold water that has been introduced and thermal expansion of the cold water occurs as it takes up fractionally more space when it is hot than colds and as a result the expansion valve opens to let a fraction of a millilitre of water out

    at the same time you have thermal conductivity from the heating cycle of the boiler element impacting the static pressure in the pre-infusion circuit when the machine is idle - you can observe this cycling of the pre-infusion idling pressure if you observe the top number on the pressure transducer console

    once the expansion valve has had to open once to relieve pressure, the next time the idle pressure in the circuit reaches its lowest point in the cycle it will be lower than the target pressure if the expansion valve pressure has been set too low and you are using a high pre-infusion pressure setting

    it is a bit of a project to explain in words, but it is sufficient to tell you that if you undo the silicone tubing hose that feeds water from the expansion valve back into the water tank where it pushes onto the expansion valve, then undo that fitting on the top of the expansion valve with i think a 19mm wrench off the top of my head that will give you access to the adjustment for the expansion valve - there is a post on it in the permanent file from memory i think, if not certainly in this forum if you do a search

    to adjust the expansion valve you want a large (10mm or better) flat bladed screw driver and turn in a clockwise direction to increase the pressure at which the expansion valve opens. i would work in increments of one eighth of a turn and then use the machine for at least a couple of hours to let it settle out as the expansion valve is simply a mechanical spring and will take a number of cycles before it settles into the new, higher, pressure at which it opens

    an eighth of a turn will have a significant impact - it might increase the pressure at which the expansion valve opens by about 0.5 bar from memory

    you will not need me to tell you that you can observe the pressure at which the expansion valve is now opening by looking to the top number on the console of the pressure transducer. if i were you i think you want it between 11.5 and 12.0 bar

    if you turn the screw in the expansion valve too high the pressure will go above 12.7 and the display will show the message 'Check Expn Valve'. This is purely a note and does indicate that you have damaged the machine in any way

    reiss.
  • third issue:

    after a boiler refill in particular you can hear the pump chopping in repeatedly to lift the pressure in the circuit

    it is pronounced because cold water has been drawn into the pre-infusion circuit up to the inlet solenoid which is closed after filling

    the hot system then quickly heats the cold water that has been introduced and thermal expansion of the cold water occurs as it takes up fractionally more space when it is hot than colds and as a result the expansion valve opens to let a fraction of a millilitre of water out

    at the same time you have thermal conductivity from the heating cycle of the boiler element impacting the static pressure in the pre-infusion circuit when the machine is idle - you can observe this cycling of the pre-infusion idling pressure if you observe the top number on the pressure transducer console

    once the expansion valve has had to open once to relieve pressure, the next time the idle pressure in the circuit reaches its lowest point in the cycle it will be lower than the target pressure if the expansion valve pressure has been set too low and you are using a high pre-infusion pressure setting

    it is a bit of a project to explain in words, but it is sufficient to tell you that if you undo the silicone tubing hose that feeds water from the expansion valve back into the water tank where it pushes onto the expansion valve, then undo that fitting on the top of the expansion valve with i think a 19mm wrench off the top of my head that will give you access to the adjustment for the expansion valve - there is a post on it in the permanent file from memory i think (https://londiniumespresso.com/permanent-file/1336-does-the-pump-stutter-on-and-off-repeatedly-when-the-lr-is-idle#15670)

    to adjust the expansion valve you want a large (10mm or better) flat bladed screw driver and turn in a clockwise direction to increase the pressure at which the expansion valve opens. i would work in increments of one eighth of a turn and then use the machine for at least a couple of hours to let it settle out as the expansion valve is simply a mechanical spring and will take a number of cycles before it settles into the new, higher, pressure at which it opens

    an eighth of a turn will have a significant impact - it might increase the pressure at which the expansion valve opens by about 0.5 bar from memory

    you will not need me to tell you that you can observe the pressure at which the expansion valve is now opening by looking to the top number on the console of the pressure transducer. if i were you i think you want it between 11.5 and 12.0 bar

    if you turn the screw in the expansion valve too high the pressure will go above 12.7 bar and the display will show the message 'Check Expn Valve'. This is purely a note and does not indicate that you have damaged the machine in any way

    reiss.
  • looking at your last two videos again, i dont think what i have written above explains what you are observing

    when you pull the lever the pumps restores pressure to the system cleanly, with no pump pulsing

    on the other hand, when the boiler refills the pump quickly restores pressure and turns off, but then it chops on and off repeatedly

    for what i have written above to explain your situation the pump should be chopping in and out when the lever is pulled too

    instead i think you have a tiny piece of grit/debris in your solenoid that is preventing complete closure of the solenoid immediately and as a result pressure is bleeding through the solenoid for a time, this loss in pressure easily being detected by the precise nature of the digital pressure transducer, which in turn calls the pump

    in reflection i think you should probably start by cleaning the solenoid and see if that cures it

    i would also recommend that you increase the expansion valve setting - do this with the pre-infusion pressure set to 6 bar as this will ensure you are covered for the most demanding set of conditions

    let me know how you get on

    reiss.
  • Hi Reiss, sorry been caught up with work and not had a chance to reply. Just a short note. Cured two of the problems, one is the sound on lever engagement. I know it was hard to hear over video but it was definitely not sounding right. Turns out it was as simple as some rattling of the digital PI module even though it was very tightly screwed on. Strange it didn't do the same on boiler fill but I guess as you said it's because it runs a bit slower. Added padded strip between chassis and PI and think that's sorted.
    Also I followed the permanent file to increase expansion valve pressure to 11.5
    That was a funny one. First of all on removal there were rings of metal that came off with the nut as if it had been missthreaded at factory and red o ring was in fact a bit chewed. Now interestingly, turning a full turn (I did start with quarter, then half ...) had zero effect on the pressure (I will upload video tomorrow). I engaged steam, pump, lever, nothing. It was just going up to around 8.5 and that was it. Also there was very little water trickling out of expansion valve during the repair (maybe 2ml in 10 min), expected more. With regards to set bar pressure, unfortunately that leads to my last problem. Anything above 4.9 causes the pump to run forever when it attempts to fill boiler. No effect with lever pull.
    Anyhow, put the expansion valve together after cleaning it up and thought I'd wait till I spoke to you.
    Funnily enough I saw the bar pressure shoot up to 12 just before putting panels back on. Interesting... Remove silicone and nut again and spend the next few minutes fine tuning the screw to maybe 3/4 turn till it read 11.5 on heating cycle and following steam or hot water draw and about 11.7 after lever pull. Now there appears to be a fair bit of water coming through the expansion valve. I'd say about 6ml per minute. as I was removing with a pasteur pipette every few moments. That is how it should be right?
    I think that has sorted the on/off blipping of the pump after boiler refill and potentially has sorted the same thing when left idle for a couple of hours. Will know tomorrow. My question is, could there have been debris such as those metal shards that had blocked expansion valve and caused these issues? Or could debris in solenoid have finally made their way out through the expansion valve and again sorted it?

    Assuming everything is ok tomorrow, the last thing I need to fix is the pump which will run forever above 4.9bar. Would be keen to get it sorted as I haven't been able to test PI above that pressure.

    Thanks again for all your help Reiss, really appreciate it. Luckily it is a straightforward machine to tinker with :)

    BW
    Christos
  • ok so as i mentioned earlier if the pump is running forever then it is unable to deliver to the set pressure

    to remedy this simply turn the pressure adjustment screw on the bottom of the pump (hanging down through the hole in the chassis under the pump) right in with a 10mm socket or offset wrench and then back it off two turns

    this will raise the pump output pressure above 6 bar

    kind regards

    reiss.
  • Just an update:

    1) Weird rattling sound sorted. Digital PI was somehow buzzing against something on the frame. Felt pads fixed the issue.

    2) Jittering pump even at low bar after boiler fill and when left on and idle for a couple hours, sorted. Tightened expansion valve 3/4 of a turn to 11.5 bar from the 8.4 it was at.

    3) Pump running forever during boiler refill above 4.9 bar, sorted. Turned screw under pump (flat head and not 10mm nut on mine) 1&1/2 turns. No issues even at 6 bar.

    Thanks for all the help Reiss!!

    2 questions:
    1)Had there been debris in solenoid, could they have exited through expansion valve? As I mentioned in last message, turning full turn first time did nothing to pressure with very few drips exciting expansion valve. Second time round I'm getting response in the bar and decent amount of water coming out of expansion valve.

    2) what are the repercussions of turning pump screw too much? Why do we need to screw fully in and then back off by 2 turns? I didn't feel much resistance when screwing mice so I went for 5 full turns at first and guess could have gone more. But I decided to unscrew to the point where it just alleviated the issue and so I only ended up with 1&1/2 turns.

    Thanks again
  • hi christos

    thank you for posting your results

    1. definitely not

    2. think of the pressure adjustment screw on the bottom of the pump as a clutch - if the water pressure on the outlet side of the pump is too high for pump to turn the adjustment screw allows the water on the outlet side of the pump to escape sideways back to the inlet side of the pump and go around again, and in doing so it provides a level of protection for the pump. if you turn the adjustment screw hard closed you remove this protection

    kind regards

    reiss.
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