Problems with flushing out water after a shot

[Dunja]

Hi all,

Our Expobar Brewtus IV (10 years old) has started having issues with flushing out the remaining water after each shot. The amount of water that comes out of the exhaust pipe (if that's the name?) is relatively small, and instead the puck is a wet mess.

We had the same issue a few years ago (after a while, no water was being flushed out, while the pressure remained in the portafilter attached to the group head), so took it for repair and a part had to be replaced (the price of that whole enterprise was 300 EUR). If possible, we'd like to fix it ourselves this time around. We already once opened the group head to clean it, so I was wondering if we could just replace some parts.

In view of this, would any of you maybe know which part(s) could be malfunctioning (and if this is a relatively common problem, would it be worth it already ordering the relevant parts out of these?) 

In addition, water has recently started dripping from the group head when the pump is off, so I assume some seals need to be replaced anyway. 

Any help much appreciated.

All the best,

Dunja

[Eric Christoffersen]

Ok I just have a guess. Something that will do you no harm to check...

First, do you own some cafiza? Some sort of coffee machine detergent? Its terrific stuff. You should periodically disassemble and boil group head parts in it. 20 minutes boiled in cafiza you'll be shocked how much tarry grunge is removed.

You really should be back flushing with cafiza every month or so. I'd do that first, chances are it'll clean out the clogged tar.

But if machine is really gummed up you probably should take it all apart and clean it. Much more time efficient.

Your picture shows the component that I suspect is jammed with tar. In your picture #10 is the main body of the group head. There's a bolt on top that screws in, there's another big brass tube thing that bolts onto the bottom of it, its the bottom thing that can get really gummed up. Unplug machine, let it cool, then use a wrapped wrench to undo both of these. Try and remember the parts assembly order, they go together in a very specific way. Pay particular attention to the orientation of short and long plungers, the springs, etc. They're all different.

Take all those parts out and boil in caffiza, if its really packed you might need to boil 2-3 times and scrape the tar off. Once everything is clean reassemble. I like to use some food safe lube on threads when reassembling, otherwise it can gall.

There's really no need to take machine in for this, the cleaning and assembly are really simple. Youve done 99% of the work just finding the parts diagram.

[Dunja]

Thanks so much for this suggestion! We unscrewed all the parts and soaked them in the descaling solution (also from Urnex), and that solved the problem.

We do have a machine detergent as well, but it seemed like a descaling solution would do a better job for how everything looked like. I'll make sure to backflush with the cafiza detergent a bit more often. I've been backflushing with water (once after each shot and 3 time at the end of the day) to avoid having to use the detergent, but it seems I should use it once a month as you suggest.

Thanks again!

Best,

Dunja