Many have heard me waxing eloquent about the Breville Dual Boiler, calling it a virtual giant killer. After two years of trouble-free operation and espresso so good it almost felt like theft to get from a $1200 machine, my off-warranty BDB is finally acting strangely. I have sung Breville's praises for backing the BDB, even for machines off warranty, and now it's my turn to see if the favor is returned.

For some on-topic espresso machine tech, here is the problem as I have identified it. After the machine is warmed up and I pull a (delicious) shot, the pump continues to run in a very reduced mode, slowly emptying the reservoir, and filling the drip tray. I have to shut off the power button to stop the motor. If I let it cool for a couple of hours and re-power it, the following happens: The pump runs in the mode it uses to fill the boiler for a much longer time than it usually does to top it off. It runs as long as it did when the machine was brand new and the boiler was totally empty and turned on for the first time. Then it warms up normally and I pull a shot... aaand? Again after pulling the shot, the pump runs continuously at a very low power setting, slowly emptying the reservoir and filling the drip tray and the cycle continues as at the beginning of this paragraph.

Question: What are your thoughts as to what is happening mechanically? Obviously some sensor is reporting something wrong to the controller and the controller is ordering the reservoir draining action. I imagine that the only path to the drip tray is through the discharge of the OPV, is that correct? So maybe a faulty OPV? Or the 3-way solenoid is partly stuck or not opening and closing through it's full range?

I'll contact Breville tomorrow and report back what they say.

-Peter

If this was a normal machine I would tell you to ground the water level sensor wire to see if the machine was somehow sensing low water level and trying to fill the boiler. But it isn't really quite normal and doing that might further damage the machine. To further complicate matters, since they do not sell parts nor (from what I have read) repair your machine, hopefully they will offer some sort of deal on a refurb unit- either graciously on a straight exchange or on a discount of some sort. But if you purchased it with a credit card, check the card company as some do give an extended warranty on purchases.

Because they do not sell parts, and that dramatically lessens the chance or finding anyone who has done any sort of extensive repairs on one of these at home, the odds of anyone having enough intimate knowledge of the internal workings of the BDB here are MUCH lower than with nearly any other machine.

What seems really strange, if accurate description of what is actually happening, is the pump running at different speeds. 99% sure it is a fixed voltage vibe pump and is not designed or intended to run at varying speeds, i.e getting varying voltage.

Then again I could well be wrong, the BDB is not a normal espresso machine using usual components. Sorry don't have a clue how to suggest trouble shooting that sucker. If I had one to play with and take apart might have a chance, but without parts available likely fruitless regardless.

A-propos of nothing but curiosity...

Mike, you're right that _normally_ an Ulka vibe pump runs off a fixed voltage. But this machine is different. Phil McKnight said that Breville has a patent on a microcontroller method of varying the output of the pump so the single Ulka pump can apply low pressure preinfusion or even lower pressure to shuttle water around from the reservoir to the steam boiler or brew boiler. Further, Bill Crossland seems to know how they do it, (if anyone would, he would).

Thanks for the input and interest so far, guys.

-peter

pcrussell50 wrote:Question: What are your thoughts as to what is happening mechanically?
I'll contact Breville tomorrow and report back what they say.

Hopefully they are able to help you out with a replacement.

Since not many of us know these machines it will be hard to guess at what the issue is, but I would think it's not a "mechanical" issue. Sounds more like a logic issue with the controller malfunctioning. Possibly gets stuck on a refill cycle? Since it works okay in the beginning, from cold machine, but once hot it will malfunction I might lean towards either a short on the controller board(s) due to moisture/debris or a faulty capacitor.
THAT'S A WILD GUESS THOUGH!!!

Hope all works out for you. Breville seems to have been quite accommodating when dealing with these warranty claims in the past.

Randy G. wrote:Because they do not sell parts, and that dramatically lessens the chance or finding anyone who has done any sort of extensive repairs on one of these at home, the odds of anyone having enough intimate knowledge of the internal workings of the BDB here are MUCH lower than with nearly any other machine.

Where did you get the idea that Breville doesn't sell parts? I've bought parts for other Breville equipment in the past & they do have some parts listed on their website.

If the pump keeps running after the shot then there is probably a fill probe issue. Also note there are fill probes one on the coffee boiler and one on the steam boiler. Additionally there are 2 pumps, one for coffee and one for the steam boiler. If you can determine which pump is turning on then you can determine the fill circuit in question.

The pump can be run from 0% - 100% by phase fire control. Similar to how newer dimmer switches work. This type of control has been used for years on Super Auto (home) machines but has only recently made it to traditional machines. This is mostly due to increased temperature control. The need for temperature control has introduced the micro-controller into most machines to read the temperature probe and control power to the boiler via PID control. Since the controller is already there it is much less costly to add the proper switching to control the power delivered to the Vibe Pump.

BillC

Dan modified the title of this thread to make it more searchable (which is fine by me), but I feel I should reiterate that when it "keeps running", it is in a very quiet, low output mode, not at the height powerof extracting the shot. The 3-way clicks as it should and flow stops and depressurizes at the group as it should. The pump that keeps running _seems_ to be draining the boiler straight into the drip tray... Slowly.

Thanks Bill. That is the kind of info I might be able to use (hope I don't have to), since it's _possible_ that the sensors it uses are standard or parts shelf stuff from some places. Phil said the vibe pump is an Ulka and I know the 3-way solenoid is a Parker-Hannifin, so maybe some of the other parts are standard also?

-Peter

JohnB. wrote:Where did you get the idea that Breville doesn't sell parts?

From posts I have read stating that even 'authorized' Breville repair centers listed for warranty service did not have repair parts but were sending the DBs somewhere, and they just supplied a refurbished unit from Breville as a replacement. Other Breville appliances I do not know about, and for minor things there have been some parts (water filters, portafilters), but finding the sorts of parts the were are accustomed to easily finding (heating elements, control boards, logic boards, valves) seem to be another matter completely. And the plastic proprietary fittings in this machine are, from all I have read, made of unobtanium. Past reports also indicate that this is even more true of the older, 'lesser' models.

I would like to be wrong about all the above. If they can market their technological marvel (for its price point) and support it, that would be great. But with all that plastic inside and the use of such a high percentage of proprietary parts, I do not see it happening.

On the other hand, with refurb units as low as $620 or so (I just searched for parts and saw that), does it really matter? At that price we can consider it a starter machine and if it lasts two to five years it has served its purpose, and then it can find a resting place at the E-waste recycler. That is a sad statement, indeed, but one that is more and more commonly accepted. At Best Buy the salespeople told me straight out that a flat screen TVs will last 6 to 7 years on an average. I just bought one that replaced my 20+ year old Proscan 34"(?) CRT. Time marches...

A POST WE WILL LIKELY NEVER SEE: "Hello. I have a twenty year old Breville Dual Boiler I want to restore and am look for some parts."

"You live. You learn. Then you die and forget it all." -R. Lum

The sensors are not off the shelf parts. They are only a rod of stainless steel. The capacitive circuit it is connected to will be the culprit if the probes are clean and look functional. Remember that there are 2 pumps (both made by Ulka) the steam boiler pump is considerably smaller so it is most likely quieter. You can remove the back panel and check which one is running.


BillC