Recently I noticed the following issues on my BDB (920):
• Shortly after powering off there would be a slight hiss from inside the machine.
• The boiler fill pump seemed to kick in more than normal.
• When opening the hot water tap, or flushing the group, the water would flow for a second or two and then stop for a second before resuming.
I took the top off the machine and found that there were a few leaks in the machine. Two were ports on the steam boiler and one was a port on the brew boiler. I removed the clips that hold the tubing in place and inspected the o-rings. They were distorted and/or damaged.
UNPLUG THE MACHINE AND ALLOW TO COMPLETELY COOL BEFORE DISCONNECTING ANY TUBING IN THE MACHINE!
I sourced silicone o-rings from Grainger (100 pieces for $8).
• 1/8 id 1/4 od p/n 1REC1
• 1/4 id 3/8 od p/n 1REC5
The process is simple:
• Remove clip using needle nose pliers or forceps.
• Pull out hose and remove old o-ring. The o-ring may or may not come out with the hose.
• Install new o-ring on the hose, insert and install clip.
Since I had more than one 1/8 o-ring fail I decided to replace all of them. I did not have any failures on the 1/4 o-rings but purchased them to very fit and to have them on hand if needed. I replaced the two 1/4 o-rings on top of the brew boilers for this purpose. If you need to replace the 1/4 o-rings on the steam boiler you will need to remove the cable ties that hold the wiring harness as the probes are too long to remove otherwise.
To replace the o-rings on the pressure gauge you will need to remove the front panel. Remove the screw on top in each corner and cut the cable tie. Gently press up on the bottom on the front panel to remove. I found it was easier to also disconnect the hose that feeds the pressure gauge from the back of the solenoid first.
As expected, most of the o-rings were in good shape. The only ones that really needed to be replaced were the ones on the boilers themselves. I would recommend running the machine for a few days with the top off, or at least not screwed on, so you can check for leaks. I did have one and simply needed to remove and reinsert the hose to seat properly.