Breville Dual Boiler Steam Boiler Leak

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by moe237 »

Hi everyone. I have been trying to find some help on this specific issue but couldn't really. Maybe I have no idea what the part number is.

In any case, in the image, the two high pressure hoses with the white fitting are leaking and preventing the steam from generating. I have no idea what replacement part to purchase and where to even purchase them as I can't find any service help here in the country.

I pointed two arrows to the valves in question and you can see them leaking in the still image.

I was trying to check them but it looks like they are glued or have some adhesive and I felt that removing them might cause more harm than help.

If anyone has any idea of how to help I would GREATLY appreciate it!


#2: Post by luvmy40 »

OK, those are just silicone covers over the o-ring/ferule/hair pin tube connection. Under those boots, it looks exactly like the tube connection next to it. You need new o-rings. I'd recommend you replace all the o-rings at the same time. If those have gone bad, the others aren't far behind.

moe237 (original poster)

#3: Post by moe237 (original poster) »

thanks for that. So you would say that the silicone covering is not doing the sealing? And would you know where to buy the right o rings from for this?

The reason i ask is that it seems that the silicone covering would be incredibly hard to put back together so if i removed it, it would probably be best to have a backup. I did notice some people have a metal piece on there i just wouldn't know what size or type that is

Thank you again


#4: Post by luvmy40 »

The boot has nothing to do with the seal. they can be removed so they can be reinstalled but they are not absolutely needed.
The OEM o-rings are #007 ... C54&sr=1-8

Some have gone with Aflas o-rings as they claim better performance than the silicone. I have no opinion on the aflas.

moe237 (original poster)

#5: Post by moe237 (original poster) »

Thank you for that. I'll post an update once it's fixed to confirm this as well.

moe237 (original poster)

#6: Post by moe237 (original poster) »


So i finally got the o-rings you mentioned. installing them was an absolute nightmare but i got it done finally.

Now it seems like just nothing is going on with the steam boiler at all. 3 beeps from the steam lever but nothing.

I did the obvious and performed the engineers reset, reset the device and so on. Would you happen to know any other tricks to get this machine back online?

I was really hoping the o-ring would do it but it seems not to have any effect. FYI the o rings in there looked worn but barely so.


#7: Post by luvmy40 »

Double check the thermal fuse for continuity.

moe237 (original poster)

#8: Post by moe237 (original poster) replying to luvmy40 »

Thank you. I'll try and figure that one out too. sucks not having a proper service center around. do you think that's checkable with a multimeter? same with the PCB board. would you know what readings i'd be looking for? and thanks for all the help


#9: Post by luvmy40 »

I have no idea what to look for on the main board. You can trace the wires from the thermal fuse and find a good spot to disconnect one side and check it with an ohm meter.


#10: Post by WWWired »

Hi moe237 . . . Superb post and I've learned a lot from luvmy40's replies which are always awesome and bang on :)

This is a two-part post reply. This first post discusses some possible steam/heat damage that can occur due to o-ring leaks; the second post, after this one, passes on some notes from another poster ("klund") from an unknown site that can't find anymore. The second post deals with ensuring all descale solution is cleared from a 920 Dual Boiler system and the water-hardness monitoring/regulation system.

FIRST POST: Steam/Heat/TRIAC possible issues:
O-ring leaks and internal corrosion resulting from steam and heat from the leaks is a very common maintenance situation with the Breville Dual Boiler BES900/920XL models and any post about this is always a great assist to the Breville Dual Boiler community. Many posts here recommend annual or biennial (every other year) complete and thorough inspection, maintenance and overhaul as needed of all internal components. Particularly the o-rings (#007 o-rings for high pressure/water hoses,and #008 o-rings for boiler probes, with a single #10 o-ring contained in the steam-wand assembly) need careful inspection and replacement as preventative maintenance, again annually or biennially.

Take a look around for any steam, heat or water damage, specifically to the TRIAC PCB assembly and see if there is any corrosion evident on the TRIAC components or on the top of the GroupHead assembly (below the smaller Brew Boiler) where steam/and water can condense/pool and that has the Grouphead NTC (Thermal) Sensor (one of three Thermal sensors on the Dual Boilers) lug-mount bolted into the GroupHead under the Brew Boiler. There are three TRIAC IC chips . . . and from what I've read in other posts here, one is to control the Brew Boiler heating element, one is to control the Grouphead heating element, and one is to control the Steam Boiler heating element. Each of these has a support system on the TRIAC PCB Assembly that involves Opto-Isolator chips, Resistors, and Film Capacitors (see the yellow looking upright boxes in the pictures of the TRIAC PCB below).

Always worth reviewing a Dual Boiler BES900/920XL's fault/error logs, ←click-here-for-how :) Post if you find anything (even pictures of your fault/error listing if something shows up) ;)

Above the Steam Boiler is the TRIAC PCB Assembly, which contains several power control components for the entire machine and is subject to steam/heat damage. There is a lot of power flowing through these components, and with the tendency for any high quality espresso machine to be run hard and put to bed wet, the possibility of heat and corrosion damage due to steam/water is elevated. But well maintained, and not run outside their specifications, these components will last decades. The TRIAC PCB Assembly is bolted/screwed into the top cover. Here are a few pictures of it for you to check it out (a new TRIAC PCB Assembly costs about $50 to purchase, but might need to hunt a bit to find one if this is the issue as with all Breville components, the inventory of replacement parts does begin to deplete and the pictures below are part of a project to identify all components on the TRIAC PCB board and define a printable circuit board computer file that could be ordered from companies that will manufacture and send these out to folks) . . . NOTE: BE SURE MACHINE IS UNPLUGGED ANYTIME REACHING INSIDE THE CASE . . .

Location of TRIAC PCB (view from back of machine with back panels off)

Removal of TRIAC PCB for inspection (and replacement if needed) . . .

Birds eye view of TRIAC PCB top-side of board (Note the white stuff on the three TRIAC ICs at left is the thermal paste residue that bonds the PCB TRIACs to the metal block Heat Sink) . . . R114, R115, and R44 all show obvious signs of steam/heat damage . . .

A closeup view of one some of the 6 the Resistors, not R44 on the board has a rupture on the right side of the Gold Band, and R114 has a rupture band encircling the resistor touching the Orange Band (the big metal block is the Heat Sink which can be left attached to the top lid when removing the TRIAC PCB Assembly, but will have the 3 TRIAC ICs stuck to it with heat paste so consider whether removing just the the TRIAC PCB or the Heat Sink with it is the way to go . . . not much force is need for these, force and technology/electronics do not mix) . . .

A microscopic camera picture of the rupture on TRIAC PCB Assembly Resistor R44 . . .

A microscopic camera picture of the rupture on TRIAC PCB Assembly Resistor R115 . . .