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Rancilio S26 -Boiler Water Level

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  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Postscript -

    I am reminded of the words of Dr Karl Kruszelnicki when he said that the internet is the greatest source of misinformation. From another forum I gleaned that the valve before the water inlet solenoid was an expansion valve. This lead me on a wild goose chase and I made some incorrect assumptions and statements. So I here eating humble pie setting the record straight.

    By analysing the Rancilio S26 electrical circuit and hydraulics, it is evident that this valve just prior to the water inlet solenoid is in fact a simple non-return valve. When the coffee switch is switched on, water flows from the mains via the non-return valve into the heat exchanger in the middle of the boiler and thence through the group solenoid valve and finally through the group head into the coffee cup! Unless there was a heat exchanger/ boiler leak it is clearly impossible for any malfunction in this hydraulic circuit to have any affect on the water level in the boiler.

    Therefore the water level in the boiler is affected by

    (1) the operation of the GICAR
    (2) the water inlet solenoid
    (3) the state and height setting of the water sensor probe
    (4) the electrical earth at the boiler

    After replacing the sick electrolytic capacitors in the GICAR, the water level in my machine was lapping the underside of the head. Far too high!

    On one occasion I found with the machine unplugged, water was streaming out of the anti-suction valve. When I disconnected the copper pipe on the outlet side of the water inlet solenoid, water was pouring out of it when clearly it should not have been. I dismantled it and cleaned it and so far so good but if it hiccoughs again I will replace it. One important thing to do, if the boiler over-fills and after you have found and rectified the true cause of the problem, is to remove the ant-suction valve and with a plastic tube syphon water out of the boiler until the water level is below the water sensor probe. It will not function correctly when the water level is far too high. For example the anti-suction valve will act like Mt Vesuvius.

    In summary it is all fixed for the time being and has been delivering cups of coffee again after such a long illness. I have learnt a lot as I knew absolutely nothing about how it worked prior to this fault. Thanks to those who have provided invaluable feedback.

    Regards
    Glenn

    Leave a comment:


  • borat123
    Guest replied
    Re: Rancilio S26 -Boiler Water Level

    Ahh, brings back memories of an autofil problem i had on the M27 a few months ago. The gicar board and components look quite similar.

    In my case the overilling was caused by a grounding wire to the boiler which I had inadvertantly left off during reassembly, after pulling everything apart for a descale....

    Leave a comment:


  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Hi Pier,

    Thanks for the feedback. Great result!

    Regards
    Glenn

    Leave a comment:


  • Pier
    replied
    Re: Rancilio S26 -Boiler Water Level

    [QUOTE=5163617067665D416D75020 link=1254876739/10#10 date=1254891708]
    I noticed as it was coming up to pressure that some water came out of the over pressure valve on top of the boiler and a little out of the group solenoid valve.  I know nothing about these machines but I would have thought that this should not happen when it is not even at operating pressure.  Can you please comment on this?  

    Hi Glenn
    The reason I thought we had the same fault with our machines is because of this comment you made about your machine above. However, from your other comments it sounds like you have a slow filling problem, which as you have noted, is probably fixed by replacing orings and servicing the autofill solenoid.

    I had a different problem as the autofill solenoid was not shutting off when the correct fill height was reached. After inspecting the auto fill box I noticed the relay contacts were fried.  With the help of an electronics expert, we replaced the 7.5A relay (In the last post I thought it was a 5A due to dodgy printing on its side) with a 10A equivalent.  "Finder" brand relay P/N 44.62.7.024.4000. $12.90AU plus delivery.

    http://australia.rs-online.com/mobile/search/searchBrowseAction.html?method=getProduct&R=253409 4

    But we also replaced the electrolytic capacitors (4 in total) as a precaution as these things tend to dry out over time. (a few bucks each) All in all about $25 worth of parts which is not bad especially when you consider a new auto fill box is $200 and still has the lower rated relay.  I have attached some pics.  Because we replaced the capacitors as well I cannot tell you exactly which part fixed it, suffice it to say, it is fixed now. It fills until it comes in contact with the level probe and shuts off after a short delay.  Level is exactly the same every time now.
    Cheers Pier











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  • maheel
    replied
    Re: Rancilio S26 -Boiler Water Level

    Originally posted by 1E2C2E3F2829120E223A4D0 link=1254876739/18#18 date=1255517346

    Leeham,

    Similarly putting in a longer water probe is merely masking the real fault.  As stated I think our friend has a faulty water inlet valve or inlet expansion valve leak.

    Regards
    Glenn
    Glenn i was talking about your machine...... I did not mean to extend the probe forever. Just to test your theroy about the gicar reading the water level then filling to long.

    I would have done it via having the machine cold, lowering the probe further into an empty boiler somehow and testing the theory.

    good luck with your repair,

    Leave a comment:


  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Hi Frabel,

    PS Re "this is a heat exchanger machine - water from the group is separate to the boiler water."

    Once again you are perfectly correct. I did not realise that at the time but am slowly learning by falling into one manhole after another!

    Thanks for your observations and feedback.

    Regards
    Glenn

    Leave a comment:


  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Hi Frabel,

    I am not talking about the expansion valve (over-pressure valve) on the top of the boiler. If you look at the water inlet solenoid you will find an expansion valve just before it. (It is at right angles to the solenoid valve). It has a copper pipe to the boiler. This is the one that was leaking on my machine.

    Regards
    Glenn

    Leave a comment:


  • damian1
    replied
    Re: Rancilio S26 -Boiler Water Level

    Originally posted by 1725273621201B072B33440 link=1254876739/13#13 date=1255500107
    In my case it was the expansion valve

    I dont get how an expansion valve (over pressure valvue on boiler?) could be a cause of excess water. Maybe this is hiding the true cause, which likely a bad seal on the autofill solenoid - or is this what you are referring to as a water inlet valve? You can take these apart and check the condition of the seal - take off the coil, then undo the 4 screws. then if comes apart and you can see the condition.

    Also reading over some of the eariler stuff:

    Originally posted by 1725273621201B072B33440 link=1254876739/10#10 date=1254891708
    In each case when it refilled after draining water from the group head

    this is a heat exchanger machine - water from the group is separate to the boiler water. So not sure why it would refill after running water through the group.

    Id be interested to know wha thte water level is after emptying the boiler, and first refill. Does it stop at a lower level, and gradually fill up from there?

    good luck, and hope you sort it out Glenn.

    Leave a comment:


  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Hi Frabel,

    I totally agree with you. I do not believe I need to (or ever would) resort to the options I mentioned but I merely stated a theoretical position rather than a practical one. Sorry if I confused people. I was thinking aloud which probably was unwise.

    Nevertheless the setting up of the water inlet pressure reduction valve is critical in getting the water level correct. As you allude to, if the mains pressure has not changed, etc, and the water level is incorrect, there is a specific fault which needs to be rectified.

    Leeham,

    Similarly putting in a longer water probe is merely masking the real fault. As stated I think our friend has a faulty water inlet valve or inlet expansion valve leak.

    Regards
    Glenn

    Leave a comment:


  • maheel
    replied
    Re: Rancilio S26 -Boiler Water Level

    I am not having a go, but do you think if you made the probe longer that the water would be lower?

    From your past posts I am thinking that you think the gicar control runs the pump for X secs longer then stops after the probe makes contact with the water. Like some sort of "timer"

    If this is correct why dont you make the probe longer? Then you could see if the water stops filling a bit lower before you mess with the GICAR.

    your thoughts on this idea?
    Leeham

    Leave a comment:


  • damian1
    replied
    Re: Rancilio S26 -Boiler Water Level

    fair enough - but it does sound like there is something else wrong with your machine then, as the depth of the probe should control it.

    Leave a comment:


  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Frabel,

    When the probe is already at the lowest position and the water level is too high, there appear to be only the options I have mentioned.

    Regards
    Glenn

    Leave a comment:


  • damian1
    replied
    Re: Rancilio S26 -Boiler Water Level

    Originally posted by 4674766770714A567A62150 link=1254876739/13#13 date=1255500107
    By the way I now believe that there are only two ways to control the height of the water in the boiler:
    (1)Changing the value of the resistor in the RC charging circuit in the GICAR
    (2)changing the inlet water reduction valve setting, ie the valve prior to the pump.
    sorry I ahvent followed the discussion, but dont you just adjust hte height of the probe into the boiler???

    Leave a comment:


  • Sacred_Cow
    replied
    Re: Rancilio S26 -Boiler Water Level

    Hi Pier,

    I am not experienced with these machines but I am in electronics. By all means replace the relay in the GICAR water level control module. I cannot see how this is going to decrease the height of the water in the boiler. If, for argument sake, the contacts were totally burnt out, and this is highly unlikely, it would mean that no current could flow to the inlet water valve solenoid and also to the pump. In other words, burnt out contacts would result in lower rather than higher water level. The electrolytic capacitors viz the 1 microfarad one affect the water level so I would replace these with 105 degree C components.

    For fault finding when the machine is overflowing, first turn it off (remove the plug) but leave the water mains pressure hose connected. Then disconnect the copper pipe on the outlet side of the water valve to the boiler and the pipe from the expansion valve just before the inlet valve. I think, as I did, you will soon find where the excess water is coming from. In my case it was the expansion valve. The main problem was the valve seat of the expansion valve had a lot of scale on it. It took quite a while to clean it with crocus paper. Also replaced the "O" ring. The water level in the boiler is now about 20 mm below the bottom of the anti suction valve threaded hole.

    In addition the central rubber sleeve of anti-suction valve has had it and we are in the throes of sourcing a new one.

    Please keep across your progress.

    By the way I now believe that there are only two ways to control the height of the water in the boiler:
    (1) Changing the value of the resistor in the RC charging circuit in the GICAR
    (2) changing the inlet water reduction valve setting, ie the valve prior to the pump.

    Regards
    Glenn

    Leave a comment:


  • Pier
    replied
    Re: Rancilio S26 -Boiler Water Level

    [QUOTE=46696062754A66696660626A626973070 link=1254876739/6#6 date=1254883265]
    Originally posted by 0C3E3C2D3A3B001C30285F0 link=1254876739/5#5 date=1254882774
    I can see the water level when I take out the ant-suction valve. It is up the bottom of the boiler head, ie the bottom of the anti-suction valve thread.  The electronic water control unit certainly turns off the pump and inlet valve after a given time.

    I have cleaned the sole probe.  It wasnt very dirty anyhow.

    Just using plain old Brisbane tap water - nothing fancy for me.

    Regards
    Glenn
    Hi Glenn
    I have been going through exactly the same problem with the S26 at work. Its been keeping me really busy!! On our machine, the problem was quite intermittant and seemed to be temperature related, i.e. when it was hot the fault would occur more frequently. The fill solenoid would click on and off but sometimes it would not flick off before reaching the anti-vac and it also sprayed out the safety valve and sent the pressure guage to about 3 bar (mains water pressure here). I also cleaned the level probe and checked all the wiring connections. I did find the earth point brass bolt was rusted, but after replacing this the problem was still there. Finally I have removed the electronic auto fill box (i believe this is the GICAR you are referring to) and found that the 5A relay had contacts that were fried. On our machine the relay (inside the GICAR black casing) has a clear casing and you could clearly see the charred contacts and plastic surrounds. Obviously underrated for the job. This relay switches the water fill solenoid on and off and is a prime suspect in the fault. I am currently waiting for a new relay to arrive and with some help from an electronics expert here we will replace it and let you know if that solves the problem. Sorry to post before we know for sure that the problem is solved, but the coincidence in our faulty machines is pretty interesting i think!
    Cheers Pier.

    Leave a comment:

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