luvmy40 wrote:The micro switch is needed to actuate the solenoid to divert flow from the group head. You can re-install the switch and adjust the outer knob position on the inner cam that activates the switch. This will give you full flow control and still allow you to open the valve fully and get water only from the spigot.

I see, I see. I think I basically did what you suggested - I ended up modifying the cam of the knob to only hit the switch when it's fully turned on, which allows full flow control and still allow you to open the valve fully and get water only from the spigot as you said.

What do you guys think is going on here? I have a backflush disk in and I'm holding my finger on the SINGLE SHOT [edit] button, which should keep the machine going at full power. My best guess is that the pump is shot. (If the problem were with the OPV, I'd be getting water back into the tray.)

I just got the machine back from the Gastrobak workshop in Germany, and they clearly didn't get the job done. I'd send it back , but ugh. The whole experience was a nightmare, and I sincerely don't want to deal with them again. Also, I'm in Switzerland and getting the machine back to Germany, then picking it up again, would be a MAJOR hassle. And finally: it so happens that I already have a new pump and brass OPV on hand, so maybe I can fix it myself and be a happy coffee drinker again ...

Well, you are holding the one cup/single shot button, not the manual button. When you hold the Manual button sown, the machine stays in pre infusion until the button is released. I just tested my BDB with both the Manual and Single shot buttons in the same way. Blind disk installed, hold the button down.

The manual button kept it in pre infusion mode and the pressure slowly rose to 5.5 bar and held until I released the button.

The single shot button went very quickly from pre infusion to full power and held at 10 bar by the OPV.

Your video shows it rising to full pressure then dropping and holding at a lower pressure. Does the pump change tone/pitch/volume when the pressure drops? It's difficult for me to hear from the video.

luvmy40 wrote:Well, you are holding the one cup/single shot button, not the manual button. When you hold the Manual button sown, the machine stays in pre infusion until the button is released.

[SNIP]

Your video shows it rising to full pressure then dropping and holding at a lower pressure. Does the pump change tone/pitch/volume when the pressure drops? It's difficult for me to hear from the video.

Ooops, my bad. I meant the single shot button - the one I actually press in the video, the one you use for a quick backflush.

As far as I can tell, there's no difference in sound, or at least very little. I just made another video, got in closer to make sure: Now that you mention it, I wonder if there's a leak in there somewhere so that the pressure isn't getting from the pump to the boiler. (Though: I would have expected to hear a hiss or see a cloud of steam. Lord knows I've seen that often enough ... )

You have a spare pump? Why not replace it and see if that makes a difference?

Ech. I know, I know.

- Since I JUST got the thing back from Gastroback's repair shop, I kind of want to go slow before I start tearing the thing apart again - maybe I got, like, confused about something? Or maybe the repair shop will feel so terrible about their shoddy work that they'll ... ???

- Also, the other pump is a brass OVP, pump upgrade mod that's built into a different machine that's ALSO on the fritz - and I THINK I need a new olive if I'm going to transfer it into a different machine. If so, I need to figure out the right specs, then order a new olive first ...

Just tossing out WAGs at this point.

I see three possibilities:

1. The pump is done.
2. The OPV is malfunctioning.
3. There is a leak in the brew circuit somewhere.

As the pump does not change it's tone and does reach a higher pressure to start, I'd save that possibility for last.

The OPV is fairly easy to remove and inspect. I've heard of a couple instances where cleaning/rebuilding it solved pressure issues.

I've also seen posted a couple times where a leak in the water line to the brew pump from, the reservoir caused low pressure problems.

I have an issue with my mods, I'm hoping someone can help! I've done a rotary mod and the slayer mod. I blanked the filter and set the pump pressure to a max of 10 bar. Pulled a shot and it was superb. 5 minutes later the pipework blew out at the back of the brew boiler down to the descaling port. I suspected I hadn't bled the brew boiler properly, so i repaired the pipe, tried again ensuring the boiler was fully flushed, and the same happened again. I suspect the issue may be because I had the needle valve closed, and the pressure sensor might be after the valve so the boiler was sitting at full pressure maybe???

Does anyone have any ideas why this might be blowing the pipework out?

I am curious at what point should I be doing preventive maintenance? replacing o-rings and such...
annually or wait for something to break?

I would replace o-rings manually. It doesn't take long at all and will save a lot of future headache.