Brewtus tripping RCD after steam boiler filled

[Sam Macaluso]

Hi,

My Brewtus Minore trips the RCD/Circuit breaker after the steam boiler is filled.

I though it could of been the element so replaced it but it's still doing the same thing.

I've checked everything else and they all seem ok.

Any tips or ideas what could be causing this?

Cheers

Sam

[Ben McCafferty]

Hey Sam—

It’s been a minute, but I’m pretty sure that the brew boiler has priority if you’re on a US/120V system. So—the boilers get filled, and then the brew boiler fires until it’s hot, then the steam boiler fires until it’s hot. 

If I had to guess, I’d say the brew boiler element is the culprit. Checking resistance may not help you, since it can be intermittent and may look fine when cold. Search my old posts on bypassing the pressurestat—that may help you for troubleshooting. You should be able to test by putting power to the brew boiler, and if it trips the breaker right away (or as it’s heating), you’ve found the culprit.

Hope that helps, and I’ll be curious to hear what you find.

Best,

b

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[Sam Macaluso]

Hey Ben,

If I disconnect the steam boiler and leave everything else connected, it doesn't trip.  As soon as I connect the steam boiler, it trips.

I'll check your posts and see if I can trace it down to something more specific by bypassing the pressurestat.

Cheers

Sam

[Todd Salzman]

You should be able to grab an ohm meter and check for continuity from the leads on the heating element to the copper boiler.

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[Ben McCafferty]

Oh! We’ll that changes things. In that case, I think you’re probably looking at the overheat sensor on top of the steam boiler. See if it isn't crusty and falling apart. Bypass it and see if it stops tripping the breaker. 

b

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On May 2, 2023, at 18:05, Todd Salzman <to...@wholelattelove.com> wrote:



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[Sam Macaluso]

Bypassed the overheat sensor and still the same.  Could it be the control board?

[Ben McCafferty]

I believe so. I saw Todd chime in, Todd?

b

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On May 2, 2023, at 19:42, Sam Macaluso <sma...@gmail.com> wrote:



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[Kevin Maciunas]

On 3/5/23 10:18, 'Ben McCafferty' via Brewtus wrote:
> Hey Sam—
> It’s been a minute, but I’m pretty sure that the brew boiler has
> priority if you’re on a US/120V system. So—the boilers get filled, and
> then the brew boiler fires until it’s hot, then the steam boiler fires
> until it’s hot.
>
> If I had to guess, I’d say the brew boiler element is the culprit.
> Checking resistance may not help you, since it can be intermittent and
> may look fine when cold. Search my old posts on bypassing the
> pressurestat—that may help you for troubleshooting. You should be able
> to test by putting power to the brew boiler, and if it trips the
> breaker right away (or as it’s heating), you’ve found the culprit.
>
> Hope that helps, and I’ll be curious to hear what you find.
>

Since it is a Minore, I suspect Sam might possibly be in a 240VAC place
:)  On my Minore-II the steam boiler heats first, there is no power to
the brew boiler until the pressurestat switches the AC supply to the
brew boiler.  They are both 1.8kW elements.  Looking at what passes for
a circuit diagram, the pressurestat, the little thermostat on top of the
boiler and the red neon are the only 'in circuit' elements when the
steam boiler is on.  I'd check there is no partial short to ground on
those first.

Ben's suggestion of hot wiring each element in turn is how I have
diagnosed where my RCD trip was happening.  There is a main feed to the
pressure stat, and it switches to either one of the others.  One is the
brew boiler, the other is the steam.   The steam boiler on mine has a
red wire.  The brew boiler is white (and so, helpfully, is the feed in
:) ).  The brew boiler is not a direct connection but goes via the
temperature control doofus, which many call the "PID" but it is not that
sort of controller :)  To isolate the steam, you can just un-plug the
red wire (on mine) and move the brew boiler wire to the terminal the
steam was on..  That'll fire up the brew side of the machine.  If it
trips when you do that, you've found an issue..  If it trips without
swapping it's the steam side.

Heating elements are prone to partial or complete shorts to ground due
to the way they are made.  A static check for resistance might not show
a fault that permits a bit of current to flow and trip the breaker.

As I'm sure everyone is aware, there is live AC supply accessible inside
the tin, so once you open it up you need to be very careful...

Cheers

/Kevin

[Ben McCafferty]

Did you bypass the pressure stat also? Those sometimes stick, I wonder if it could somehow cause the symptom. 

b

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On May 2, 2023, at 19:44, Ben McCafferty <bmac...@me.com> wrote:

I believe so. I saw Todd chime in, Todd?

[Sam Macaluso]

Yes, mine is 240VAC.  I just replaced the pressurestat with a Mater XP110 0.5 - 1.5bar

[Sam Macaluso]

Still the same problem :-(

[Ben McCafferty]

Shoot. Hmmm

Sent from my iPhone

On May 2, 2023, at 20:46, Sam Macaluso <sma...@gmail.com> wrote:

Still the same problem :-(

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[Ben McCafferty]

Only other thing I can think of is the water level sensor rod in the steam boiler. Maybe it’s shorting to the boiler case?

Sent from my iPhone

On May 2, 2023, at 21:02, Ben McCafferty <bmac...@me.com> wrote:

Shoot. Hmmm

[Sam Macaluso]

Funny you say that because if I disconnect the water level sensor from the control box, it doesnt trip but causes the pump to activate, as soon as I plug it back in, the pump stops and it trips.

I'm assuming its tripping because the pressurestat is sending power to the steam boiler.

I've tested for continuity between the rod and the boiler case and nothing.

Got me stumped!

[Sam Macaluso]

Still can't trace as to what is tripping the RCD when the steam boiler kicks in. I've replaced the element and it's still doing it!!

[Kevin Maciunas]

On 15/5/23 08:19, Sam Macaluso wrote:

Still can't trace as to what is tripping the RCD when the steam boiler kicks in. I've replaced the element and it's still doing it!!

On Wednesday, May 3, 2023 at 2:28:53 PM UTC+10 Sam Macaluso wrote:

Funny you say that because if I disconnect the water level sensor from the control box, it doesnt trip but causes the pump to activate, as soon as I plug it back in, the pump stops and it trips.

I'm assuming its tripping because the pressurestat is sending power to the steam boiler.

I've tested for continuity between the rod and the boiler case and nothing.

Couple of things:

(1) If you move the STEAM boiler connections to the BREW boiler, then turn it on - does it trip?  That isolates the element.  Don't, of course, leave it like that for more than a minute or so!  If it trips still, then the fault lies with the wiring back to the mains supply somewhere, OR,

(2) Does it trip when the pump runs?  Could be something with the pump..  Mine has an Ulka vibratory pump and a reservoir, given how the pump is made it'd be difficult to get a fault to earth; but it's still possible..

Assuming (2) is OK, the stuff in circuit is the thermostat at the top of the steam boiler, the pressurestat and the associated wiring - including the red Neon on the front panel.  If you disconnect the wire from the boiler and power it up and it trips, then the fault lies up that path.  This is the same diagnostic as (1) but without a high current load.  You can remove the connectors from the thermostat and short them together to isolate that.   The pressurestat can be removed from circuit by shorting the mains feed wire to the wire feeding the element/thermostat.  On mine, the neon plugs in too, easily removed.  If those fail to produce a win, I'd be looking at the physical wires and connectors... 

My machine is 240VAC, and doesn't seem to have exactly the same circuit diagram as is shown in the "Brewtus Compendium" PDF you can download from the group files, but the steam side is identical so I assume yours is too :)

While it is tedious being systematic, you do need to be systematic...  A multimeter is helpful, but sometimes fails to find high impedance shorts that only show up when significant voltage/current is applied.  Plus you need to remember to constantly un-plug the machine while messing about internally...  At least, that's what I do having been bitten by something someone else 'turned off' once :)

Cheers

/Kevin

[Ben McCafferty]

Great thoughts Kevin! Wholeheartedly agree.

One other thing that occurred to me vis-a-vis the diagram. In the US model, Exposer had to make it so our anemic 15A circuits in older homes could handle the load, by prioritizing one boiler over the other. Not sure if this is true in your models or not, and if not, perhaps there is something happening with the brew boiler instead, i.e. if both are able to heat at the same time?

This one is being stubborn, but you’ll have it soon enough!

b

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[Ben McCafferty]

Haha, exposer. Gotta love auto-correct. Ahem, Expobar.

Happy Monday to ya!

b

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