Breville Dual Boiler Steam Boiler Port Repair, Lower Side Wall

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

#1: Post by gchapman »

Last Saturday I posted that my BDB was tripping my GFCI wallplug circuit but seemed to work well from a neighboring wallplug. After looking for leaks and finding none, and after thoroughly drying it, I believed that the problem was my GFCI circuit, not my BDB.

The thread is here:
Breville Dual Boiler Short? or GFCI Failure?

I spoke too fast! The problem returned, and upon careful examination, I found evidence of moisture inside - but I could not find the leak. Every now and then, but only every now and then, I would hear a steam leak from the general area of the steam boiler. I have seen these ports put out a little plume when leaking, and have fixed them before, but I couldn't find anything resembling that. I began to wonder whether the leak was an occasional leak from the lower side port on the inside wall of the steam boiler, just under the boiler support frame. It is very hard to see... Looking at it carefully it seems this is a steam boiler to OPV tube, I think?

Today, when it tripped the GFCI again on startup, I decided I was going to go after it. After reading up on HB, I was able to find several others who had suffered this and fixed it. All of them said it was hard to get to and they had to remove some unspecified hoses to gain access. Somewhere there is a thread on this with details on the fix and pictures, I have heard, but I couldn't find it after several searches. So I thought I would start a new thread on this specific leak to help others. Please add to it!!

Here were my steps:

1) Investigation. The presenting problem was the GFCI tripping. After a thorough drying, all worked well. So a steam leak  moisture  a short on the Triac circuit board seemed to be the likely problem. I wiggled every port repeatedly to try and identify the source of the leak, but could not induce the sound of a steam leak by this - or reduce it when I could hear it from time to time. I placed tissue paper over the upper ports and then a dental mirror, looking for signs of moisture. No luck. Because I had changed two of the upper-port o-rings recently, I did not think one them was likely. But I looked carefully. I had found out about the lower port on the steam boiler during my reading, but I did not know where to look. After more research, I knew it was on the inside center wall of the boiler, so I put a very bright light onto that area, took my phone camera, put it on a macro setting and managed to get a good look at the lower side wall port. It clearly had grey mineral deposits around it!!! Finally!!!

2) Clear an approach to a hard to reach port. I would have *loved* to have the notes from others who fixed this, but didn't, so... I took off the solenoid valve to clear the way. Easy enough, 4 screws on the corners does it, using a correctly sized screwdriver. The solenoid seems clean, which is evidence after 13 months that my water strategy is working and not leaving deposits inside the boilers or elsewhere. I unclipped the yellow w green stripes wire from the solenoid and the brew boiler. I left all tubes intact and left the two white washers in the mating seat that receives the solenoid, making reassembly easy.

3) Come up with a strategy to replace the o-ring and re-seat the tube. As you can see from the photo below, once the solenoid is out, the visual line to the port is much better, but the needed room to grab the clip is tight! Plus the head of the clip is pointed down, making me guess that originally the hose was secured in the port from below during initial assembly! I would have to pull the steam boiler to gain that kind of access! Not doing that. So... I took my hemostat forceps (a very cheap, helpful tool to grab those clips w/out dropping them), threaded it through from left to right (working from the front of the machine) level to the height of the port (see photo below), and locked onto the head of the clip. I used a screwdriver to push the tip of the forceps down, freeing the hose. Out it came! The o-ring was not in good shape (see photo below)!!

4) Replacement. After swapping out the o-ring and cleaning everything w my fingers, I tried to use the forceps, coming down from above, to grab the hose and wiggle it back in. It did not easily go in, and I worried about damaging the hose. I looked at threading the hose back in through a couple of different paths that would not require the normal bend right at the port, but it was not long enough. If I had the ability to make a longer hose for this fix, I would have done it. I don't and didn't. In the end, it went back the way it came out. I used very small 3" screwdrivers to push it back in, positioning my screwdriver in the same placed I had the forceps, parallel to the height of the port, using the screwdriver to push the black fitting at the hose end from side to side. But it would *not* go the last little bit needed to fully seat the o-ring and enable me to reinsert the clip. Finally, I took some silicone grease and waxed the o-ring and hose end (in spite of Jake's warning not to use silicone lubricant with silicone o-rings) and it went right in!! Used the forceps to reinsert the clip this time from above, not below. That will make it easier next time.

5) Final Steps. I dried everything out thoroughly with a hair dryer, replaced the solenoid, buttoned it up and turned it on. Perfect startup, and the machine is dead silent when on. No small hiss, anywhere. Wonderful!!!

Take-aways. This was complicated, and required some patience and dexterity, and perhaps some luck and silicone grease. The clips are so easy to drop into the unreachable lower darkness of this machine; I did drop one. I have done this before, and it means taking the machine and turning it upside down over a plain, flat surface and gently shaking it. Take the water reservoir out first!!

These kinds of repairs are probably ok for those of us who enjoy these kinds of mornings, but it is easy for me to think a lot of well-intentioned folks would just *not do it*. I would guess that a lot of people would just send it back to Breville if it was under warranty or maybe paying the extra $350 if their warranty has expired - hoping maybe you would get a refurbished or new one back. I'll bet Breville doesn't replace this o-ring it you send it back! Or if they do, I would love to watch a video of it!

I love this machine - meaning I love the espresso it makes, and the way so very many things have been thoughtfully designed, and the way we have been able to repair and mod it. It is a lot of value for the $. But this repair was a bit of a wake-up call for me, because I know that it would be the end of the road for too many people. This port connection, being so unreachable, should have been redesigned like the port connections were on the top of the brew boiler back in 2018, with nuts instead of o-rings. Or made more accessible... or something!

But I am glad to get it done and hope someone else can add to this thread with an even better way of doing it. We will have to learn how to do it, it seems.
Geoff Chapman

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#2: Post by DaveB »

Congrats on a job well done, and most excellent writeup! It's a bit worrying that the leak happened after only 13 months, if I am correct in assuming you got it new. But great to know that the fix can be done by a determined mortal.
gchapman wrote:The clips are so easy to drop into the unreachable lower darkness of this machine; I did drop one. I have done this before, and it means taking the machine and turning it upside down over a plain, flat surface and gently shaking it. Take the water reservoir out first!!
Ha! I dropped a clip while doing the Slayer Mod and also shook the machine upside down, and was quite relieved when it came out. I thought it might have been gone for good!
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gchapman (original poster)

#3: Post by gchapman (original poster) »

DaveB wrote:It's a bit worrying that the leak happened after only 13 months, if I am correct in assuming you got it new. But great to know that the fix can be done by a determined mortal.
Ha! I dropped a clip while doing the Slayer Mod and also shook the machine upside down, and was quite relieved when it came out. I thought it might have been gone for good!
Thanks, Dave. It *was* only 13 months; got it new; I agree on 'a bit worrying'. And 'a determined mortal' is probably the right phrase! When I flipped it to retrieve my clip, I had my wife hold the top for me. That helped.

Love your "Pseudo-Slayer™". :D
Geoff Chapman


#4: Post by DaveB »

gchapman wrote:Love your "Pseudo-Slayer™". :D
Thanks. My first choice was actually Slayer in Sheep's Clothing™, but that's a bit long-winded for my profile. 8)

So if I'm understanding correctly, the hose leading to the leaking connection was one that you wiggled looking for the source of the leak, and it didn't reveal anything? In any event, I'm thinking it would be good to pop the top every 6 months or so and wiggle all the high-pressure hoses checking for leaks; I left the 4 lid screws out for this purpose.

Question about forceps: I've never owned any, but see that inexpensive ones are available of various lengths - and curved or straight. Is there one you would recommend as the best all-purpose for BDB? Or more than one? Here's an example showing different types:
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#5: Post by pcrussell50 »

At the rate Dave keeps trademarking our language he'll have the money to buy a new Slayer (or slayed BDB) for every day of the week from our royalty payments to him :wink:

LMWDP #553

gchapman (original poster)

#6: Post by gchapman (original poster) »

If Dave can find a way to monetize our phrases... I suspect we are all in!!! :D

Meanwhile, back to my forceps! I never knew there were options. Here is my $6 cheapo's... the important thing is the ability to lock on, and some mild grooves at the gripping end, like small pliers. I probably would have liked a small curve at the end also, but mine are straight. ... 61X3HA54TA

Geoff Chapman

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#7: Post by lancealot »

Kudos Geoff.
I did this repair a year or so ago. It was a bit of trouble. This documentation will certainly help some else out in the future.

There is another bridge for us to cross in DIY repair, long term user, BDB land. The Oracle uses the same boiler configuration as our BDB's. In the thread linked bolow, in post #5 is this bottom of the Oracle steam boiler. You can see that the same pin, collar, o-ring and tube system is used for the boiler drain line. The photo in the thread shows evidence of a massive leak at the O-ring for the drain. I have not seen or heard of anyone replacing these. I cannot tell from the linked thread, how the thread starter got good enough access to this area to take the photo. The fact that they got the photo gives me hope that the o-ring replacement is do-able. One day...

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#8: Post by pcrussell50 »

There is also a hard to reach one underneath the two ports of the group complex, for hot water. AFAICT, you'd have to loosen the group or remove it enough to flip it into an orientation where you could reach that port.


I have yet to see, or recall seeing, a leak from a water tube. Only steam. The Oracle one Chris pointed out excepted of course.

What remains up in the air is whether Breville would invest several hours in a fix, or send out a new machine?

LMWDP #553

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#9: Post by lancealot »

I kinda wonder if the hard to inspect water leak locations self seal? An argument for mineral laden water perhaps :lol:


#10: Post by littleyip »

I'm the owner of that Oracle and can attest that the mineral deposits appear to have def sealed this same leak. I live in an area with pretty hard water and the Oracle was used for a long time, many times per day, in my office before I acquired it. I was never able to fix this side boiler o-ring as OP has done, so kudos. I think the Oracle is harder to access than the BDB so I will not be doing it. As for the photo of the bottom of the boiler, it was very difficult to take that photo. It was taken using a phone camera pointed through a hole in the bottom of the machine.