Go ahead and read the first post in this thread. It is a fairly comprehensive write up in the common things that go wrong. I think this situation is item 3.

Breville Dual Boiler Mods and Maintenance

trimbalim wrote:Steam circuit leak as in one of the entry points has a leak? Or something else?

The o-ring seals on the PTFE tubing in and out of the steam boiler, including the one on the side of the boiler by the solenoid and the line to and from the steam valve. Could also be the water level probes on the steam boiler. The water level probes have two o-rings. Either or both could be leaking. I recommend changing all the o-rings on a semi annual basis. They are cheap and it's only a couple hours work.

athoangphan wrote:Yes, I'll take pictures tomorrow and share. Meanwhile, there is a 12v DC power off of the main PCB which provides power to the water tank's LED light, a pair of red and black cables (red=positive, black= negative), you could tap into, which I did. I forgot to measure the amperage, but the DC power is strong enough to power couple LED lights which I prefer since I only want subtle lighting. These LED lights only go on when the machine is on and off once the machine is turned off.

Where the 12v DC port is located on the main PCB: image

Mine reads 2.5v is this the US BES920XL?

I just got into home coffee habit and about to pickup a Dual Boiler tomorrow. I appreciate this BDB "bible" of a thread so much. Thank you for such an increadible legacy.

The DB I'm pickup tomorrow is a 3 years old machine. Former owner said he's been doing descale often and has just done one last week.

What and how should I check to make sure the machine is working properly?

I don't think he has replaced the o ring and what not that are mentioned in the #1. Should I replace them all?

This DB has not been modified. I intent to do try all the flow control mods. However, I am also very curious about dimmer mod on DB, because I haven't found any one done it. Is dimmer mod on DB possible?

-Quang

If the owner says he's descaled frequently, make sure the steam boiler is heating before agreeing to a price. There's very a good chance that the thermal fuse for the steam boiler is blown. I'd still pop the solenoid off and check for sign of scaling. I don't like calling anyone a liar, but the odds that the descale was run at all, let alone frequently and the fuse didn't blow are slim to none.

Yes, replace all the o-rings and check for leaks with the top off.

The dimmer mod is not necessary with the BDB as you can program the pre infusion pump power and duration from the settings. With a very quick and easy modification to the water valve knob, you can have very good flow control without opening the machine. Or, you can do the full blown "Slayer Mod" with a bit more effort but no $.

Thank you for your advices! I will be steaming some milk to test it. o-ring is on the way.

Just got my dual boiler and very excited to get started! Question on water - if I'm using filtered water already, so I also need to use the filter that Breville provides within the water tank?

As long as your water quality is high based on your current filtering there is no need, but not all water filtering is equal so YMMV. The include filters have historically been resin for softening hard water, so it's to help those of us with hard water.

StickSticklyHere wrote:Just got my dual boiler and very excited to get started! Question on water - if I'm using filtered water already, so I also need to use the filter that Breville provides within the water tank?

You will want to run several tests on your filtered water.
Test for chlorides. Not Chlorine or chloramine.
Test for total hardness.
Test for alkilinity.

I would recommend using a variation of the rpavlis recipe regardless. It's just the safe way to go.

Hi there, I'm fairly new to the BDB. Had going strong for last 12 months.
But yesterday I had trouble with my steam wand pressure. It happened suddenly and at first i thought it was my poor milk frothing skills. On closer inspection it seems that the steam pressure has dropped.
Now I know somewhere in these 990 posts this has probably been discussed but i cant find it. and was hoping someone could offer suggestions.
WHat i have already tried:
1) cleaned the wand head. No blockages there.
2) cleaned BDB just for the heck of it
3) emptied the water tank, added new water, opened the descale screws and emptied water from espresso and steam. Refilled.

I was going to use the descaler powder the machine came with it but on dissolving in the tank it was a horrible brown crystalized powder and dissolved into a brown water. It didnt look right so threw it away.

Anyway. I havent been able to fix the steam yet. It does still steam but is lower pressure than previously. B4 going ahead and opening the machine i was hoping someone might have a suggest please?