Breville Dual Boiler leaking - thank-you all

#1: Post by **colebatchd** » August 30th, 2023, 7:20 am

Hi folks,

I had the same problem as Breville Dual Boiler - Brew boiler overheating to 225 degrees, and have changed all o-rings (available https://www.ebay.com.au/itm/384391273957 for my fellow Aussies), however:

1. I appear to still have a small amount of steam inside the machine - not sure if this is normal or not (no major hissing when wiggling the tubes)
2. The LED indicates temperature continues to rise (normally 93C, I see it rising up to 110C but am purging steam through the hot water tap at that point)

I presume somewhere there's a circuit board that controls the temperature - is this the one on the underside of the lid, or is it behind the LCD display? I'm asking as trying to figure out what/where I need to dry out to see if that's the problem or not.

Thanks all, this place is super helpful, I've read so much here (although never posted before this).

Cheers,
Dim

August 30th, 2023, 4:09 pm

Update:

The temperature probes (I think that's what they are) are definitely emitting steam, I may have broken them in my repair efforts?

And the boiler never stabilises (gets up to 114C but never stops flashing) so I can't pull a shot. Set to 93C.

I think I'm off to a shop. Welcome any input.

#3: Post by **chilltrout** » August 31st, 2023, 4:24 am

You have a failed triac on the triac board stop using it before you melt the steam probes or blow the thermal fuse.
It's failed on and the PID circuit cannot modulate the triac chips so it just stays closed circuit and keeps heating until it blows the resettable fuse or the non resettable fuse.

You will need to replace the triac board or replace the chip on the board.

The triacs fail from being bombed with steam they are directly above the leaky probe.

You can buy a new set of steam probes on eBay if they have a leak from the stem otherwise you can just replace the 010 oring on the coupling.

#4: Post by **mcudogs** » August 31st, 2023, 5:39 am

You should make sure that you have the machine unplugged if you are touching things inside the machine. The steam boiler can be at mains potential under certain fault conditions and the coffee boiler terminals on the top can also be live even with the machine turned off.

August 31st, 2023, 9:53 pm

chilltrout wrote:You have a failed triac on the triac board stop using it before you melt the steam probes or blow the thermal fuse.
It's failed on and the PID circuit cannot modulate the triac chips so it just stays closed circuit and keeps heating until it blows the resettable fuse or the non resettable fuse.

You will need to replace the triac board or replace the chip on the board.

The triacs fail from being bombed with steam they are directly above the leaky probe.

You can buy a new set of steam probes on eBay if they have a leak from the stem otherwise you can just replace the 010 oring on the coupling.

Thank-you. That's exactly the sort of help I was hoping for.

Parts ordered...

#6: Post by **WWWired** » September 1st, 2023, 1:55 am

Hi colebatchd

Have you checked the fault/error logs? This will be a good starting point to narrow this fault

To access your BES920XL Error/Fault Log:

Using the Control Panel, shut the machine off;
Hold the single and double shot/cup buttons together (at the same time) for 5 seconds and then turn your BES920 on again;
When the Service Menu appears, press "menu button" and this will display your BES920's shot counter (divided by 10)
Then you can press the menu key again and that will let you view/scroll through the fault/error log in ascending order from 00 to 12

Here's what the various "fault" (not LCD "err#") codes mean on the BES900 and BES920 models:
00 ... Steam Boiler NTC open Error ........... (shows up as "err1")
01 ... Steam Boiler NTC short Error ........... (shows up as "err1")
02 ... Coffee Boiler NTC open Error ........... (shows up as "err2")
03 ... Coffee Boiler NTC short Error ........... (shows up as "err2")
04 ... Grouphead NTC open Error .............. (shows up as "err3")
05 ... Grouphead NTC short Error ............. (shows up as "err3")
06 ... No Water In Steam Boiler
07 ... Water over-flow condition in Steam Boiler
08 ... Coffee Water Flow Failure
09 ... No water in Coffee Boiler detected at Boot Up
10 ... Coffee NTC Sensor Over Temperature
11 ... Steam NTC Sensor Over Temperature
12 ... Grouphead NTC Sensor Over Temperature

Mark down the ones that show anything other than a 00 after the first two digits and colon. So for example, if you have "03:51" displayed when scrolling through the error/fault log, record that number, and report back here what you find for further consideration

September 4th, 2023, 5:03 am

chilltrout wrote:You have a failed triac on the triac board stop using it before you melt the steam probes or blow the thermal fuse.
It's failed on and the PID circuit cannot modulate the triac chips so it just stays closed circuit and keeps heating until it blows the resettable fuse or the non resettable fuse.

You will need to replace the triac board or replace the chip on the board.

Thank-you! Triac board replaced, and I can now pull a shot. I've ordered (and have) replacement steam probes but haven't replaced them as I thought I should do one thing at a time.

WWWired wrote:Mark down the ones that show anything other than a 00 after the first two digits and colon. So for example, if you have "03:51" displayed when scrolling through the error/fault log, record that number, and report back here what you find for further consideration

Thank-you!

The non-zero codes I have are presumably because I've overheated previously?

10:10
12:03

I presume that means these have been triggered at some point? How do I understand the details in the error codes?

Thanks all,
Dim

September 5th, 2023, 4:53 pm

Bump to see if someone can tell me what these error codes mean?

I think I need to replace the steam probe - definitely more condensation inside the machine than I'd expect.

September 6th, 2023, 8:18 am

10:10
12:03

So I now understand that the "mm" in the "nn:mm" notation is the number of times that error has been triggered. Makes perfect sense. Now reset all to zero.

And for those following along at home (or looking back at my foolishness from a time after now) it seems like this is what I have:

Breville Dual Boiler BES920 - Temporary fix for leaky steam probe

I will definitely be replacing the steam probes. Weekend job.

September 9th, 2023, 9:22 pm

Thanks all for your help. Now back to 100% function. Appreciate your help @chilltrout and @WWWired in particular. Thanks to your help I saved a 4 week wait, and who knows how much I would have spent in coffee during that wait, before we even talk about how much the repair would have cost.