JRising wrote: This suggests that the water in the brew circuit is escaping while the machine idles at temperature. Because the boiler idles above boiling temperature, if the circuit isn't completely sealed the steam will just continuously expand and excape while the liquid water boils to replace it, it takes very little time for little Breville boilers to boil nearly dry if the leakage is enough to see.

Can you determine by touching components where the steam is escaping? Example, there should be no flow from the boiler backward through the pump. If the pump outlet fitting is hot when the machine is at idle, it is because steam is flowing that direction and backward through the pump, or backward through the checkvalve on the air-release valve if there is one.

This is a very insightful post. Though not entirely applicable to the BDB. The BDB brew boiler actually idles cool. Anecdotally evidenced by the fact that the brew boiler almost never requires the o-ring replacements that the steam boiler requires every couple of years... It never develops "hissers". The BDB has multiple heaters in the brew path, including the final one in the group itself, which is "actively" heated, IOW it is PID controlled and it delivers whatever amount of heat necessary, to hit the temperature the user sets in the display, on a Scace test. IOW, the BDB's multiple PIDs were tuned using Scace so that the selected temperature in the display, is what you would get on a Scace test... NOT what the brew boiler temperature is.

This does not mean that the pump isn't allowing some amount of back flow that it shouldn't, which is a useful observation. The pump is the "industry standard" Ulka that many other prosumer machines use. It's the higher spec one though, with 52W instead of 42W and the 2on/1off duty cycle vice the 1on/1off duty cycle in the more common Ulkas.

-Peter

stangah wrote:What preinfusion pump power are you using? I found kind of inconsistent results at the stock 60% value, but bumping it up to 70% made the pump kick in sooner and more regularly

I have been operating at 60% for 6 years without having had any variation. I still did the experiment without seeing any difference. thanks for your interest

pcrussell50 wrote:Correct me if I am misunderstanding. I think you have said:
Test 1: hits 10.5 bar in 5 seconds
Test 2: hits 10.5 bar in 4 seconds
Test 3: hits 10.5 bar in 4 seconds
Test 4: "idem" I do not know what "idem" means

-Peter

Hello, At the first extraction, the pre-infusion lasts 18 sec instead of 8 sec. Then the pump starts at full speed and reaches 10.5 bars in 5 sec. The other 3 experiences are all normal with pre-infusions of 7 sec. As already mentioned the problem only presents itself with the first extraction. To get around the problem I run hot water and then I perform my extraction which in this way is normal each time. Today I am examining a track proposed by JRising.

JRising wrote:
This suggests that the water in the brew circuit is escaping while the machine idles at temperature. Because the boiler idles above boiling temperature, if the circuit isn't completely sealed the steam will just continuously expand and excape while the liquid water boils to replace it, it takes very little time for little Breville boilers to boil nearly dry if the leakage is enough to see.

Can you determine by touching components where the steam is escaping? Example, there should be no flow from the boiler backward through the pump. If the pump outlet fitting is hot when the machine is at idle, it is because steam is flowing that direction and backward through the pump, or backward through the checkvalve on the air-release valve if there is one.

Hello, I checked for steam leaks as suggested, I couldn't spot any. However once the temperature has been reached of 93C (200F) I hear from the side of the boiler associated with the steam, the sound of a leak and the water which immediately evaporates. Despite my patience I was not able to determine the location. I have used the 1 cup filter basket and cleaning disc several times without noting anything in particular. To get around the problem I run hot water and then I do my extraction. Thank you for your precious collaboration

Hello, I checked for steam leaks as suggested, I couldn't spot any. However once the temperature has been reached of 93C (200F) I hear from the side of the boiler associated with the steam, the sound of a leak and the water which immediately evaporates. Despite my patience I was not able to determine the location. I have used the 1 cup filter basket and cleaning disc several times without noting anything in particular. To get around the problem I run hot water and then I do my extraction. Thank you for your precious collaboration

There is a fitting on the side of the steam boiler, approximately 9:00 as viewed from above. There is a PTFE tube coming from the steam filler pump. That is the one o-ring that is a little more challenging to change because working space is tight there. But if it is leaking, it must be changed because it will eventually get worse.

-Peter

PTI!
Marc mentions his backflush reaching 10.5. Even after a near full turn counterclockwise, mine still reaches 11.0 exactly...using my just received stainless blind filter. Is he a bit low, or am I a bit high? I'm curious as to why his steam boiler would have anything to do with his PI to full pressure issues?
Marc, excluding ME, you are in good hands here!!

IMAWriter wrote:PTI!
Marc mentions his backflush reaching 10.5. Even after a near full turn counterclockwise, mine still reaches 11.0 exactly. Is he a bit low, or am I a bit high? I'm curious as to why his steam boiler would have anything to do with his PI to full pressure issues?
Marc, excluding ME, you are in good hands here!!

Doubtful that the leaky fitting has anything to do with the pressure the machine registers while pumping against the blind basket. That is more likely do the the OPV adjustment.

pcrussell50 wrote:There is a fitting on the side of the steam boiler, approximately 9:00 as viewed from above. There is a PTFE tube coming from the steam filler pump. That is the one o-ring that is a little more challenging to change because working space is tight there. But if it is leaking, it must be changed because it will eventually get worse.

@

Marc100 wrote:

This is a more challenging one to repair but it is do-able. I have changed it twice. Once cause it needed it, and another time for sport.
It goes a lot easier if you remove the solenoid valve and the other tubes that are in the way. Take a photo of everything before you get started.
Geoff was good enough to take pictures and do a write up. The only thing I'd do differently is take the two teflon tubes out of the base of the solenoid. THese can be seen in his 4th photo down going into the base of the solenoid on the left side.
Reville Dual Boiler Steam Boiler Port Repair, Lower Side Wall
You'll need hemostats so you can remove the clip without dropping it into the machine. O-rings are #007 silicone.

Post #66. Breville Dual Boiler - fixing leaks and other maintenance
Use the wire trick in photo 2 to make it easier to put the clip back in without dropping it.

First of all thank you to the group for allowing me to identify my problem. After reflection I decided, based on the technical information provided by several, to venture into the repair. I order the same parts as BHENNESSY of the same supplier, since I am in Canada myself.
Can someone give me the reference codes or the sizes and type of pipes that make up the plumbing. Once the parts are in hand and if my BDB does not let me go (6 years of wear in December) I am waiting for the winter to attack the beast. Thank you again for your precious collaboration.

P.S. The quirks in my texts come from the fact that I am French speaking and that I use the Google translation software.

The tubing that the water and steam flows through its 4mm OD, PTFE. The o-ring seals that terminate each of these tubes are sized #007. Breville used silicone. But many users in the community have been experimenting with other materials such as EPDM and AFLAS.

It would be unusual if you needed to replace any tubing. Usually just the o-rings age and need replacing. PTFE lasts a very very long time.

-Peter