Expobar Office Leva 2 - Brew pressure drop during extraction - Page 2

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
User avatar
cafeIKE
Posts: 4686
Joined: 18 years ago

#11: Post by cafeIKE »

It's unlikely raising to 1.4bar would make much difference.

Do you purge the steam boiler BEFORE steaming and brewing?

My SOP for DB and HX prosumer e61s
  1. Purge steam boiler
  2. Prep shot
  3. Open steam tap to engage heating element & close
  4. Start brew
  5. Start steam at first drops

zablaine (original poster)
Posts: 8
Joined: 1 year ago

#12: Post by zablaine (original poster) »

When you say "Purge Steam Boiler", do you mean just letting some steam out?

I typically let a bit of steam out (and clear any water in the steam wand), then steam milk until almost complete, and start espresso shot when milk is nearly finished steaming. This means finishing the espresso and milk and the same time, but I can vary the order if it helps avoid this annoying issue.

What's most strange and frustrating about this whole thing is that I have had the same basic workflow for many years, and this issue is new.

User avatar
cafeIKE
Posts: 4686
Joined: 18 years ago

#13: Post by cafeIKE »

Yes, let some steam out so element is on when shot starts. This prevents a pressure drop during the shot. My workflow is lock in PF, start brew, pick up filled pitcher and begin steaming at first drop or so. Milk and shot are ready nearly simultaneously, so a quick rap and pour.

zablaine (original poster)
Posts: 8
Joined: 1 year ago

#14: Post by zablaine (original poster) »

Update: I seem to have resolved this issue.

I do not know for sure what fixed the problem, but I have two theories:
  • One of the Solid State Relays was overheating and not functioning properly
  • The pump water feed tube was somehow getting crimped by the vibratory pump running
The action that resulted in the symptom going away was relocating the SSR from the front wall of the espresso machine to the base. However, in doing so I also moved the water lines, which pass by the vibratory pump on the way to the tank. These were the only two things that changed.

There are two reasons for suspecting the SSR:
  • When I repaired a few other things (around when the issue started) I re-insulated the boiler with much higher R value (ceramic fiber) insulation, causing the inside of the machine to remain much hotter where the SSR was located
  • The issue would rarely happen when the machine initially warmed up, but was almost universal once it'd be hot for more than an hour or so.
Regardless of the root cause, hoping this helps someone in the future in some way.

zablaine (original poster)
Posts: 8
Joined: 1 year ago

#15: Post by zablaine (original poster) »

Update: I seem to have resolved this issue.

Update to update: I have not resolved the issue, and it still happens (sometimes multiple times per shot) on many shots. Other times it doesn't happen at all.

I've re-read the full thread a few times, and I'm at a loss what could be causing it. Have fully de-scaled twice, and that doesn't seem to be the issue.

I've replaced the pump, and think we can rule out the electrical side of the pump, as well as the crimped hose theory. Manually crimping the water supply hose during extraction causes the pump to struggle, but the pressure at grouphead doesn't drop to instant zero.

I took apart and cleaned the solenoid. I am at a bit of a loss. I do agree the "bang" sounds like the solenoid, but I'm not sure where to go from here.

zablaine (original poster)
Posts: 8
Joined: 1 year ago

#16: Post by zablaine (original poster) »

Adding some additional observations that may be useful:
  • The pressure does not drop when the backflush disk is in place and the machine is at pressure. Pressure seems steady.
  • During extraction, the pressure typically drops at least once, sometimes more than once, and sometimes not at all
  • When the pressure drops, it can happen during pressure build or once the shot is already at 8-9 bar, seems random
Talking to the WLL support folks, it sounded like the Solenoid could indeed be at fault, though it's a very strange issue. Going to take it apart and clean it again before attempting to replace.

Wondering if somehow the solenoid slipping (preventing water from entering the boiler) and causing pressure drop.