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Breville BES920 - Not reaching temperature

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  • Allen
    commented on 's reply
    Might I have a similar problem? I have a Breville Dual boiler BES920 purchased almost exactly 3 years ago. Made a coffee this morning and switched it off. Switched it on again at lunchtime when it immediately showed a temperature of 111 ºC . I realised the unit was VERY hot, so switched it off at the mains and let it cool down. Some hours later I plugged it in, switched it on using he power button and it showed 42 ºC. Switched it off but left it plugged in, and on switching it on again a few minutes later found the temp had risen to 55 ºC . Something astray with its entrails. Assume it's a job for the repair shop?

  • PeteRepeat
    replied
    We have success.

    ​​​​​​Replaced the triac board and a few orings (I got limited supplied so to be continued).

    The good old bes 920 (7+ years old I think) is back to life.

    However the brew head heats up slower than the steam boiler on cold start which is unusual. Does the pid learn or are they fixed gains?

    Leave a comment:


  • PeteRepeat
    replied
    Hmm. Whne I took the NTC sensor off it had a seperate loose metal tab, that I just put between the NTC sensor and the group head... I wasn't sure what order it went on, and I originally thought it was just a ground wire I figured it'd be fine (yes I know grounding is also important, but if I had realised it was for temperature I could have paid more attention.

    Do you know if it was meant to be two pieces plus the screw and in what order they should have gone on?
    ​​​​

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  • WWWifi
    commented on 's reply
    yes indeed, that is the temperature sensor that is feeding your Groupheads PID controller data The lug (the metal terminal with the screw hole in it) is wrapped around what appears to be a square-ish item. That square just between the wires and the screw hole is the NTC Sensor. The NTC Sensor is likely encased in a heat resistant, water resistant, polymer. The metal of the lug (the terminal connector you screw onto your Grouphead) transmits the thermal energy from the Grouphead to the NTC Sensor (the square-ish thing the shoulder of the metal lug is wrapped around).

    It definitely looks like a Ground Wire . . . the give away that is more than a Ground wire is the square electronic component (the NTC Sensor) that has two wires (not one), one sending current in, and one receiving current out (both going to a connection on your brain-box of your BES.

  • PeteRepeat
    replied
    Oh so that connection on the top of the group head is the NTC sensor? I thought it was a ground when I pit it back on just recently to the new group head. I t looked ok re corrosion but I thought it was a ground when I pit it back on.

    Leave a comment:


  • PeteRepeat
    replied
    Thankfully the insides of mine look good, no corrosion on top of the old group head when I replaced it just now (only due to old single piece collar = very early 920).

    Thanks. I realised I only replaced the fuse.

    Seems I have the original NTC sensor as well from your good description. Does that mean a new boiler if that goes? Like my group head when the collar went... However there's no signs that has a problem is there, more for future proofing it? I know the triac board has issues as I can hear the heat element turn on say a second after the system turns on, then it doesn't turn off when at temp (confirmed with volt meter as well). Also confirmed the element hasn't shorted to ground and it has the correct resistance, well I think.
    ​​
    ​​​​Yeh I have a multi meter and know how to use it without blowing myself or the machine up 😁

    Leave a comment:


  • WWWifi
    replied
    Here's an example of what failed seals on a Brew Boiler can inflict on a Grouphead in a BES900XL or BES920XL Double Boiler system if not checked on annually or every other year . . . two pictures, one showing the corrosion that can occur on the Grouphead's NTC Sensor and the second showing the over all Corrosion on the Grouphead area due to water intrusions from the leaking seals on the Brew Boiler . . .
    Breville BES900XL BES920XL Grouphead NTC Sensor showing Corrosion due to Brew Boiler Seals leaks
    Breville BES900XL BES920XL Grouphead NTC Sensor showing Corrosion due to Brew Boiler Seals leaks

    Leave a comment:


  • WWWifi
    commented on 's reply
    There are two possible Fault Codes for Err3. Fault 04 and Fault 05. Fault Code 04 is for an "Open" or disconnected circuit (as can be seen above in the picture) in the Grouphead NTC Sensor. Fault Code 05 is for a "Shorted" circuit, which can cause breaker tripping, and still function, giving inconsistent or intermittent readings, until it fails completely, likely entering the "Open" state where current no longer has a path through the NTC sensor at all.

    NTC Sensors are created commonly by combining ceramic and rare earth metal mixtures and are often encased in a material of some sort, a heat resistant polymer or glass even, to protect them from the elements. They are well esteemed for their superior precision and accuracy in monitoring and regulating temperatures within a specific range. Over time, these NTC protective jackets/coatings can be damaged by heat or water/steam erosion of just corrosion of other kinds (of which there are several). I'll attach a picture of a particularly nasty Grouphead corrosion issue that ended up destroying the NTC sensor and generating an Err3 fault (which may mistake for Fault 03, Coffee Boiler NTC short, which it is not).

  • WWWifi
    replied
    Originally posted by PeteRepeat View Post

    After fixing the thermal fuse on the boiler, it's now only over temp on the boiler. All other temps (group head and steam boiler) checked in diagnostics are ok.. The bubbling I hear and the obvious positive pressure indicated by the leaking orings seem to indicate boiling occurs approaching 100 degrees 😲

    So who knows maybe I could have replaced triac only (??) but decided a board was only like $40 so less risk.

    hopefully all ntc sensors are fine... couldn't remove them from the boiler without brute force.

    Thanks for all your info. very informative..

    ​​​​​
    There's a "thermal fuse" (the bottle cap sized white-ish thing) and then there's a NTC Sensor that is used by the Brew Boiler's PID controller. There are two types of these NTC Sensors that insert into your Brew Boiler . . . the new NTC Sensor has a Retainer hitch/hair pin clip that secures the NTC Sensor in place after being pushed into place, and the older version of NTC Sensor is threaded into place. As with many things Breville, after their warranty parts inventory is depleted, Breville legacy model owners must find generic part sources (something being done increasingly and shared as information on sites like this). Your Brain Box is likely not the issue. The NTC Sensor on your Brew Boiler is the possible source for this fault.

    Do you have any photos of your brew boiler from when you opened it up and did previous replacements of components? While you likely didn't need to replace any of the components you mentioned above, it's excellent maintenance and will extend your BES' life and basically turn it into a new machine at those component locations

    If you have the old style NTC Sensor, it will be screwed into place, and sits just to the posterior (on the side) of the brew boiler from the Thermal Fuse (whitish bottlle cap, slightly smaller than actually, sized item) . . . its not on top of the boiler but on the right side of the brew boiler (the smaller boiler) if you are facing the machine from the front).

    Looking at the picture above, you can see the NTC version that has the hitch/hair/pin clip (that has to be carefully pulled out first) before removing the NTC Sensor, which actually is in contact with the Brew Boilers water. If you have one that looks like it has a box wrench fitting, you'll have to screw it out carefully. Before you do that, you'll want to test it for continuity etc. using a Digital Multimeter (DMM) if you've got one?

    Leave a comment:


  • PeteRepeat
    replied
    Originally posted by WWWifi View Post

    Which component is giving you the ". . . never anywhere near 93℃" reading? Is that your Grouphead temp or your Brew Boiler temp?
    After fixing the thermal fuse on the boiler, it's now only over temp on the boiler. All other temps (group head and steam boiler) checked in diagnostics are ok.. The bubbling I hear and the obvious positive pressure indicated by the leaking orings seem to indicate boiling occurs approaching 100 degrees ?

    So who knows maybe I could have replaced triac only (??) but decided a board was only like $40 so less risk.

    hopefully all ntc sensors are fine... couldn't remove them from the boiler without brute force.

    Thanks for all your info. very informative..

    ​​​​​

    Leave a comment:


  • PeteRepeat
    replied
    I have ordered a new triac board and some boiler orings. This machine is refusing to die just yet... Just can't justify the money for a bes980 or what I was even more tempted with the bes990 until this thing has a major component go...

    Leave a comment:


  • level3ninja
    commented on 's reply
    What are all the possible reasons for Err3?

  • WWWifi
    replied
    Here's a few pictures of the BES900XL and BES920XL Grouphead NTC Sensor and Brew Boiler NTC Sensor locations . . .
    Breville BES900XL BES920XL Grouphead NTC Sensor Location Click image for larger version  Name:	Screen Shot 2022-03-26 at 2.48.46 AM.png Views:	0 Size:	1.31 MB ID:	907045To answer level3ninja's question about the oddity of the Error Fault Codes and "err" codes not corresponding, I'm not sure why Breville has this unusual discrepancy except that some "err" codes might correspond to more than one "Fault" condition . . . here's an example of the err3/Fault code 4 listing:
    Breville Dual Boiler Fault ver err code discrepency
    Attached Files

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  • WWWifi
    replied
    Originally posted by PeteRepeat View Post
    As per the title, but I'm still not sure what's wrong thus another topic on this.

    Brew temp doesn't get to temp. Ive had the odd power trip but could never be sure what caused it.
    . . .
    Hi PeteRepeat

    "power trips" can be caused by faulty components in an appliance (or in the case of a BES920XL impressive level of design and manufacturing, a "machine"). This can be caused by an open or shorted circuit in a component, such as an NTC (Negative Temperature Coefficient) Sensor, creating an excessive demand for voltage/current thus tripping a breaker. This breaker tripping is a good thing, not only because it protects the wood your home is constructed from, but also your valuable Espresso machines components, such as heating elements and brain box etc. The symptoms you describe appear to be related to temperature monitoring regulation.

    There are several NTC sensors on your BES920XL PeteRepeat These are designed not only to help regulate temperatures within your boilers and Grouphead heating element etc. but also to protect your machine in case of over-heating, corrosion, or other failure.



    Add to this that the Breville Dual Boilers (BES900/920 series etc.) utilize two PIDs (Proportional-Integral-Derivative controller), one of which is on the Brew Grouphead and the other PID on the Brew Boiler (the smaller of the two Boilers above the Grouphead), and you have a complex mix of magic and sorcery to deal with.
    1. If your NTC Sensor on your Grouphead is shorting (if it was open the machine just would not reach "ready" state), then you'll be getting over-voltages and possible "power trips" (as you describe your breaker tripping, particularly if you have GFCI, Ground Fault Circuit Interrupter, protector type breaker).
    2. If your NTC Sensor on your Brew Boiler is shorting (again, if it was completely failed and "open" the machine would not heat at all), then you may also potentially experience "power trips" as your machine cause and over-voltage spike as it attempts to draw more and more current from the electrical circuit.
    As you are experiencing a "power trip" and depending on what temperature your 93℃ unreached target is relating to (the Grouphead temperature or the Brew Boiler temperature), you may have a situation where the PID cannot carry out its algorithm to reach set point properly . . . particularly if you have a failing or shorting NTC Sensor that is not providing consistent or stable data to the PID program. Noise on a thermal component (as in a shorting NTC Sensor) in particular can result in the output bouncing around and this interferes with achieving set point and loop performace in the PID.

    NTC Sensors have a lifespan. Over time their ability to accurately monitor temperatures can drift or become incapacitated. Operational one minute, they can be a hot-mess the next minute. NTC Sensors are brilliant for their incredible precision within the ranges required by Espresso Machines. However, when they begin to fail, due to long term heat exposure or other factors such as corrosion etc., they can begin to give errant readings.

    You'll need to check your NTC/Thermal Sensors, and one or more may need replacing. While its true that temperature stability is regulated via a "heat-exchange" loop between the Steam Boiler and the Brew Boiler, this shouldn't cause your breaker to trip (a "power trip") as its a passive system component with no electrical connections.

    Which component is giving you the ". . . never anywhere near 93℃" reading? Is that your Grouphead temp or your Brew Boiler temp? I assume because you are targeting 93℃ you are referring to your Brew Boiler but the Grouphead temperature is also monitored.
    Last edited by WWWifi; 26 March 2022, 08:33 PM.

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  • level3ninja
    replied
    Yeah the steam can cause an earth trip

    Leave a comment:

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