I own an Izzo Duetto MK4. Bought back in 2014. I have serviced it a few times and has been a great learning tool. Recently I noticed that the coffee seemed weak and a cursory look at the brew pressure gauge identified a low pressure of around 4 bar. I also noticed the backflush was weak. So I stripped the e61 down and lubricated ( molykote). the backflush problem was instantly cured but the pressure remained low. I decided to adjust the brew pressure screw and after reaching the maximum adjustment I now have 9 or so bar pressure but more importantly great coffee again.

Although it would appear there is no problem now I suspect myself the OPV is playing up as why do I need to adjust to maximum the brew pressure? Compensating for a leaky OPV maybe?

I have phoned BB and spoke to a technician who said the OPV has nothing to do with it. if the pressure is low then the pump is at fault. I am sceptical. My question is:

  1. Can a faulty OPV cause low pressure?
  2. If that is the case where is the water going to? as there is none coming out of the little tube by the tray. The machine is plumbed in.
  3. How difficult is it to change an OPV on the izzo?
  4. Where can I find the part if I need to?
  5. Is it maybe the pump?
  6. What symptom’s should I look for?

I should point out that about a year ago I cleaned the OPV as water was constantly coming out of the little tube by the front tray. That rectified the fault at the time.

Don’t get me wrong the coffee extraction is perfect but I feel with the brew adjustment on maximum is not right.

    coffeealex

    1 Can a faulty OPV cause low pressure?
    2 If that is the case where is the water going to? as there is none coming out of the little tube by the tray. The machine is plumbed in.
    3. How difficult is it to change an OPV on the izzo?
    4. Where can I find the part if I need to?
    5. Is it maybe the pump?
    6. What symptom’s should I look for?

    1. It can.
    2. It would be being returned to the tank (in quantity) via the tube from the Expansion valve (OPV). Have a look and see if this is happening when pulling a shot against a blind filter. If it’s not, discount the expansion valve.
    3. It’s easy
    4. Bella Barista or most internet espresso machine spares retailer, the part is quite generic. Remember this part is only to vent excess hydraulic water pressure due to water expansion on heating. It has no part in brew pressure regulation as in a vibration pump machine. It’s unlikely to be the cause of your problems (as you have described them)
    5. Yes, most likely

    The things to watch for are each symptoms cause stated in order of probability:

    • the brew pressure needle showing back and forth variations, e.g. from 5 bar to 9 bar or 7 bar to 9 bar etc.. (balanced bypass playing up, seizing pump, failing capacitor)
    • funny noises (pump seizing up, balanced bypass)
    • the motor sometimes failing to start (capacitor)
    • Pump struggles to make pressure (damaged/worn vanes, motor capacitor)

    Make a good quality video (with sound) of a shot pulled against a blind filter, upload to YouTube and link to it here. Show the brew pressure gauge

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        Thank you for your answer. I have uploaded the video. As previously mentioned it does reach pressure ok but the brew pressure setting is at maximum. The guy at BB said at the time that in his opinion the valve was stuck and that by turning the screwhead i freed it and so the pressure went up and is now ok. Does not explain why I needed to turn it so much to get it back up again. Excuse my ignorance in this.

          coffeealex was the motor/pump always that noisy?

          Can you show a photo of your pump and what you adjusted. Look at the weep hole in the pump connection to the motor, has water been coming out?

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            I have posted a few pics. The screwhead (acorn shape) is shape is what I adjusted clockwise. I think the weep hole is that pipe and it looks dry. The noise has changed. It was more like a wow wow sound before and the case made a vibration sound. Now the vibration from the case has gone and thinking about it it does seem a bit louder.

            Another pic from top. Also had a look at water tank to see if water is going back to it and it is bone dry. The green stuff on top of the brew boiler I am assuming is a previous leak to maybe when I replaced the temperature probe as although it looks green it is dry .

            Well a few things…that tube is a waste of time….it does nothing to protect the motor bearings. I wrote this article after the MK1 Duetto was launched. You may well need to inspect yours…torch and spanner required.

            http://coffeetime.wikidot.com/duetto-pump-checks-and-home-made-leake-detector

            you should take a video with the top off and the camera on the pump…shot against a blind filter…oh you can leave the pump running for more than 3 seconds after the pressure maxes.

            The machine needs a serious clean in side and the bottom below all the components and boilers. A clean machine allows you to see problems faster then if it’s still leaking, fix the leaks, esp on top of the brew boiler.

            • What water are you running?
            • Have you owned it from new, or did you buy it used?
            • What does your servicing entail, what have you replaced?
            • Take a photo from the top at a greater distance, we might spot other problems for you.

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            Listened to your great advice and started to clean it.

            • The water is coming through a bestmax premium filter
            • Yes i have owned from new. Purchased in 2014 from BB
            • replaced temp probe on brew boiler. Opened up OPV and cleaned after it was constantly losing water from tube into drip tray. Problem solved after cleaning inside of OPV. Have cleaned and lubricated cam on brew lever about 9 times. cleaned filter under brewhead and replaced later. Changed gasket seal under brewhead. Recently stripped all of e61 , top( mushroom) and bottom and cleaned as water was not backflushing with any force. Now it does after clean.

            Looks much better, now you can see where leaks are coming from. I’d double check the hardness of your water.

            Pump or motor sounds noisy, split pump from motor and check for leaking.

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            Thank you Davec. I have never removed a pump before so can I check the procedure please.

            • Make sure the machine is off and cold
            • loosen 2 nuts: 13mm and 17mm
            • loosen screw from collar underneath pump and lift body of pump upwards
            • check underneath pump and in well for signs of water leakage.

            Is the above right? Thanks

            I have found this link which seems to explain which nuts to loosen :https://clivecoffee.zendesk.com/hc/en-us/articles/360001221713-Izzo-Duetto-Pump-Replacement

            The more I think about it the more I don’t think the pump was ever this noisy, so I am starting to think along reason 4 you mentioned earlier

            DavecUK Pump struggles to make pressure (damaged/worn vanes, motor capacitor)

            This is a great learning curve. I really appreciate you passing your knowledge on.

              4 days later

              Oh well. I think its game over. I loosened off the pump and I think water has been going into the motor. Does that mean a new motor and pump would be needed? The odd thing is it works still ok? Is the loud noise coming from the motor rather than the pump? I am no expert and far from the inspirational knowledge of Dave C and others, but surely is that not a stupid design to put a pump over a motor that way or am I way too ignorant to see the merit?

                coffeealex but surely is that not a stupid design to put a pump over a motor that way or am I way too ignorant to see the merit?

                I’m not sure how else you would connect the pump rotor to the motor’s axle. I mean, yes, there are belt/chain and gear drives, but they take up space (and cost) and there is no requirement for them if you can get the motor’s speed and torque to match the pump’s requirements.

                From your first photo, I thought you had snapped the axle, but in the others it simply seems full of scale. I suspect that the noise (and possibly fall in pressure) is because some bearing is jammed by rust and/or scale as a seal has failed. If they are standard size bearings and the seat has been designed for replacement, it’s not game over at all - cheap and relatively easy to replace… although yours may be not as easy, given the amount of scaling.

                  Thanks, I was thinking more could they not have put and motor sideways on so that if it leaks it goes not directly into the motor or some flexible waterproof seal at that end to protect the motor?

                  I might be talking absolute rubbish as a novice, but my theory is that the vanes in the pump have gone which has led to a drop in pressure and the leaks as the vanes stop water escaping and thus maintain pressure. The noise is a result of water affecting the bearings in the motor with scale and or rust causing friction and an increase in noise. Love to hear what DaveC and others think

                    coffeealex Unfortunately it’s exactly as expected. When I did the top level design for the MK1 Duetto, they didn’t do everything I asked for. The pump couldn’t be mounted horizontally, there wasn’t room

                    I recommended strongly the motor was caged with the pump at the bottom not the top to prevent exactly this problem, then the weep hole would have drained the water before it damaged the motor bearing. I even did them a detailed drawing, but Izzo refused to do this stating I was wrong and it wouldn’t be a problem….so I wrote the Wiki article I referred you to. I think finally in the MK4 they caged the pump motor combo and flipped it upside down.

                    Quick mill also did an upright motor pump config, but listened and had the motor at the top and the pump below as I specified for the Verona model. I also had them obtain a document from fluid-o-tech approving the pump in that configuration, as the only previous approval was for a Horizontal mount.

                    Run the motor without the pump head on and see how it sounds….if it’s noisy, replace it. If it’s not noisy, clean it up, whack a bit of Molykote around the spindle and hope for the best. The pump definitely requires replacement.

                    If after putting a new pump in the motor is noisy under load, then your going to have to replace it.

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                      coffeealex The motor has an axle that rotates. That cannot be in any other place than in the centre of the motor ('s rotor). The pump also has an axle that rotates, and cannot be in any other place than in the centre of the pump ('s impeller). If you don’t align (and mechanically connect) the two axles, you need to have another way of transmitting motion from one to the other… i.e. a drive of some sort. Yes, you could place the motor above the pump, but that creates all sort of other issues with heat management.

                      At a minimum, there is a seal around the pump’s axle. That has probably failed because of scaling (and they are meant to be replaced regularly - they wear out even if there is no scale). There may be more than one, and/or there may be additional seals on the motor’s axle.

                      EDIT - after having seen DaveC’s comment, I understand better what you meant; disregard this post!

                        Thank you for all your help. I learned a lot from it. Just one final question: to run the motor with the pump disconnected from the rotating spindle do i just turn the brew lever as if i was extracting coffee?

                        I will also start some new discussions as I am most likely going to buy a new machine as have been saving up for this day. I have got down to a profitec 700 or lelit bianca. most importantly I will also try to understand if I can use osmio zero for the new machine as this experience has made me realise that the number i criteria for a reliable machine is good water. I would put that at number i priority

                          coffeealex yeah run motor without pump connected, so you can hear the motor bearing…it’s probably shot, but most of the noise could be coming from the pump. You can lift the brew lever to start the motor…it should be almost silent.

                          Osmio Zero is a fine move because as you rightly say, good water gives great reliability from 98% of problems usually caused by water. The Duetto pump motor orientation always irritated me, especially as they wouldn’t listen. I designed it a long long time ago now (probably 17 years ago) and they basically worked of that old design with only slight incremental improvements. in it’s day it was ahead of the game…17 years on, not so much. I did help Lelit with quite a bit of stuff as well….so I know it’s a good machine. I had the Version 3 Bianca for about a year before it was released…nice machine especially the hi/lo flow ideas.

                          The black one they have looks good, but I didn’t like it when I saw it back in may, with the lighter coloured wood…I advised them to use the darker walnut with it……so hopefully they will either offer that as an option or make the standard a darker walnut.

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                              DavecUK Thank you. I have had the izzo for some time and although I may end up cleaning the motor and replacing the pump I will sell it advising anyone what I have done. Believe its always good to be honest. I would not keep it as even if I got a new motor and pump this does not change the overall design flaw. They definitely should have listened to your advice as I think you were way ahead of the game at the time. So now looking at Osmio zero and lelit v3. Cannot grumble at the Izzo though as has delivered great shots and enabled me to learn some servicing skills that hopefully are transferable to the Lelit

                                  coffeealex For sure, you will have learned loads and can enjoy the challenges of profiling and a more modern machine. I still have my Duetto serial number 0001, but I have not used it for a very long time…still looks new. I keep it for sentimental reasons.

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                                    coffeealex I should have mentioned, if the pump motor is screwed (pump deffo is), you could always replace it with a Vibration pump…save a lot of money and if you sell it, as it’s an old machine, probably won’t affect the price that much.

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