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L1(2012-2016) leaking issues

Hi everyone,

Checking in because I'm having an issue with my L1, and after giving it a quick once over I'm not sure what to try. Apologies in advance if I'm vague, I'll try to upload a video if possible to help.

The L1 had been on most of the day when I came to it found the pump making an unusual noise (more sputtering than anything I've heard it do before), and water leaking from under the unit. I shut the machine off, checked that there was water in the tank, which there was.

After cleaning up and a cool down, I switched the machine on and as it started to build pressure, water began to spill from the anti-vac valve. I assumed that my boiler had overfilled, which seemed likely given we've very soft water here and it has done this once before, maybe 18 months ago.

I opened the hot water tap and emptied the boiler (at length) until the pump came on, which it did for a little while before switching off and the low water alarm came on (plenty of water in the tank). However, I now had a new leak of water around the bottom of the pump and leaking under the unit - too much to have been from the small anti-vac leak that started before I opened the hot water tap.

I'm at a bit of a loss now, so thanks in advance for for your help!



  • It's best to open the side panels and watch carefully where the water is coming from. Should be easy to spot since there's not just a few droplets. Take snapshots / video of those details, and it should be clear to see what needs to be done.
  • Thanks for the reply Frans.

    I'd already got the sidepanels off and took a video, but struggling to upload it right now (wrong file format etc.)

    I've taken the attached pictures just now. I put some water in the tank, placed the tank back in the container and the water started leak immediately (i.e., before I'd turned the machine on). There's probably not much you can tell from the pictures though that said.

    However, I can't see where exactly the water is leaking from, although it's running as though it's coming from under the tank? I certainly can't see it dripping from anywhere now.

    Attached files

    image image image
  • I can't see anything leaking in detail there. Best to get a pocket flashlight, get up close and show what is leaking exactly.

    Video: upload to a Youtube account, share the link in the message also works.

    Could it be the water reservoir being not seated well?
  • Good idea. Couple of videos here; you can see that the base of the unit is dry and then when I seat the tank it begins to leak through.

    (taken just now with flash on, it's a bit clearer)
    (video taken earlier when water alarm came on)

    It sounds as though you're right, but I don't understand why this has started happening now to be honest. The tank feels like it has fit properly, as securely as I can get it, and no differently to how I've fit the tank previously... I'm also not sure why this would start being a problem spontaneously; it's not as though I started having the problem immediately after putting the tank in, unless I'm complicating a different problem with a new one now.
  • You write "when I seat the tank it begins to leak" -- do you pull out the tank? Why and how frequently? If it sits well, best to leave it.

    The rubber seal/ring in the 'nipple' could be worn out over time.

    The videos are not very clear, in the first one I hear something's happening (pushing on the tank? Invisible on screen) and it's best to see exactly where the water appears. Anyway from your description it sounds like the tank 'nipple' if that the right word. The part that slips into the corresponding part in the chassis.

    So best check that in detail, clean, NOT lubricate (!) and fit again.
  • Generally speaking, I rarely take the tank out except maybe once a year (if that) for cleaning. The last time I did that was maybe a few months ago. However, I'd taken the tank out in this scenario because leaving it in would have meant all the water leaking everywhere.

    Apologies for the lack of clarity in the videos, it's the best I can do really - to be honest, even in person it's not very clear where the water is coming from. In the top video, I start filming with the tank out and then put it in place (so to show the water leak as it begins), which is probably what you can hear me trying to do. In any case, the tank appears to be firmly in place.
  • hello

    i think you have multiple issues

    1. the boiler over filled, probably exactly for the reason you described. you took the correct action to remedy it. the alarm would have sounded for the same reason

    2. having addressed the boiler over fill, and today is a new day, presumably with the machine dry again inside the casing from the heat of the boiler, look again to see if the pump is leaking. if it is it needs to be replaced - expected life of this pump is around 3 years. there is a very detailed post on how to replace the pump in the permanent file

    if you discover that the leak is from some other location, please let us know

    kind regards

  • Thanks for picking this up Reiss.

    Tried filling the tank again, and this time, after craning my neck a bit, I was able to see water actually dripping from the pump, so hopefully that's the mystery resolved. I've had four years out of it, so no real surprises if they generally last around three like you say.

    Found the guide in the permanent file, so I'll get on to replacing that.

    Thanks again both of you for your help.
  • So a follow-up on this one, I'm worried I've created myself a new problem.

    New pump arrived today and I managed to fit that without any problem, so far as I know.

    However, now when I turn on the machine, it comes up to pressure and the anti-vac valve doesn't close, meaning it continues to leak steam until the machine is turned off and drops back down to no pressure. The valve does close at that point, so it doesn't seem to stuck. I can depress the valve at pressure, but it pops back up when not pressed.

    Certainly wasn't doing this before - is there something I might have done wrong in replacing the pump? Or is there maybe something else I should try?
  • hi fran

    the anti-vac valve exists to prevent a vacuum forming in the system when the machine is turned off, which is likely to result in 'false pressure' when the machine is turned on next time (i.e. it tricks the pressure switch into switching the immersion element off at an artificially low pressure, and so the system runs cooler than it should)

    to perform this task our anti-vac valve is open when it is in the down/resting position, which occurs when the system has less than about 0.3 bar in it. when the boiler has more than about 0.3 bar in it there is sufficient pressure to lift the weight of the centre pin in the anti vac valve upwards, causing the o-ring on the centre pin to seal

    if the anti-vac valve is popping into the up (sealed) position, but failing to seal it either has a bit of grit or muck between the valve seat and the o-ring (most likely), or the o-ring has gone hard with heat, or it is nicked/split/cracked/otherwise damaged

    if you take a 17mm wrench and a hammer to strike the wrench to shock the anti-vac valve free from the boiler you will be able to remove the valve off the boiler

    only once you have removed the anti-vac valve off the boiler should you remove the stainless steel circlip that holds the valve together; the centre pin will then fall apart from the valve body and you will be able to take the o-ring off the centre pin to inspect its integrity

    let us know what you find

    kind regards

  • Ignore, just testing response times on long threads.
  • Thanks for explanation, Reiss. It's certainly useful to know a bit more about how things work, particularly if you're someone with zero idea on these things like me.

    I've been waiting on getting the correct spanner for the job; however, before going any further, I thought I'd make sure I'd got the source of the leak correct (which, in turn, involved waiting for a cardboard roll to become available). Anyway, I was wrong. The steam is coming from the safety valve.

    Now I've looked at some of the older posts about resolving this, which suggest I'm best having a go at trying to get the valve to close before I think about removing it. Bearing in mind that, like I say, I've no experience doing this kind of thing, how do you recommend I go about this please?
  • hi från

    if its the safety valve im assuming its the first generation of safety valve, in which case there is no point in mucking around with it

    remove the old safety valve and fit the new design of safety valve that we now offer; it is infinitely better

    contact me when the new valve arrives and i can help you via video call to change the safety valve

    be sure to use a hammer to strike the wrench to shock the valve free from the boiler

    kind regards

  • The new safety valve has arrived now, so this weekend I'll look at removing the water box and then maybe we can arrange a Skype call to make sure I don't go about removing the old valve the wrong way.

    Could you let me know what size spanner the safety valve takes please?
  • oh im not sure off the top of my head - i think it is larger than a 17 as the anti-vac is 17 - might be a 19, but if i had to guess i would pick 22

  • ps - please dont take the water box out; it is not necessary
  • Hi Reiss,

    I've only just been able to get round to looking at this after having some trouble getting the spanner and other things getting in the way. Two weeks of aeropress coffee I could have done without...

    I'm afraid I've only just seen your follow-up message about not taking the water box out - I've already moved this out of the way, and I'm now in the current position. (pictured)

    Is this more or less correct? My understanding is I need to strike the end of the spanner with fair amount force to try to shock the valve loose. I'll hold off for you to confirm this though, as I obviously don't want to get it wrong. I'll ideally have someone to hold the boiler too.


  • hi från
    that will work, although the wrench is riding close to the side of the anti-vac valve
    i suspect you will need to place the wrench above the fine copper pipe that supplies the pressure gauge (be careful not to drop the wrench on this fine pipe) so the wrench is at an angle above the horizontal so the wrench can clear the top of the anti-vac valve as you strike the wrench towards the right (counter-clockwise) with the hammer
    i appreciate this isnt textbook in that the wrench is no longer square on the nut on the safety valve and as a result the nut will get mashed a bit but the old valve is going in the bin and the new valve has the nut machined on it halfway up the valve so the wrench can be held level and still miss the anti-vac valve

    kind regards

  • Managed to replace the valve yesterday and now everything seems to be back in working order.

    As you suggested, I did need to angle the spanner at times. Loosening the valve, it only moved incrementally so I was having try a few different positions to try and get some purchase on it, but it was pretty straightforward in the end.

    As always, thanks very much for your help. Enjoying a somewhat quieter pump and looking forward to an espresso fuelled week.
  • thanks for reporting back Fran. reiss,.
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