Advice needed.VBM piccolo pressure jumping

[flosurdo]

Hi all,

First post on CS. Just purchased a VBM piccolo 2nd hand. Couple years old, just unpacked it last night.

I can manage to get aome really nice shots out of it but it sounds like it's struggling at times.

During a shot, the pressure gauge goes up to 8 bar then quickly skips down to about 5..then bounces between 5 and 10 during the shot.

Any thoughts would be much appreciated!

Cheers

[Dragunov21]

Does the pump sound like it's labouring? That combined with the pressure readings would indicate something's amiss with it. I'm not sure if these pumps can be pulled apart but if you're comfortable with it you might do that to have a bit of a look/clean and see if it's just a little bit of crap caught in it somewhere.

[flosurdo]

Thanks for the reply,It's hard to tell if it's labouring because it gets up to 8 bar then almost does a small pop and drops down..then up and down again...weird

[MrJack]

I wonder if the pump could be cavitating? Could there be a blockage at the inlet?

Also, does it still happen without the portafilter in the group?

[flosurdo]

Without the portafilter it has no problems

[flosurdo]

I'll have to check the inlet.otherwise I think it's a trip to the mechanic.thanks again for the replies

[sprezzatura]

Late reply: did you sort out the pressure issue? I was going to suggest experimenting with the OPV. Sometimes they stick and/or partially stick. Try turning the adjustment screw (big slot head) a full turn clockwise and then anticlockwise; then plug the machine back in, turn it on, let it come to pressure and try pulling another shot.

[sprezzatura]

Addendum: does the drip tray fill with water quickly when pulling a shot from the OPV waste line? It should only bleed/drip out a small amount of water when the reciprocating pump is on.

[Pretzal]

I'm inclined to agree with Sprezzatura. It sounds very much like an issue I was having with my Vibiemme Domobar Super. Once the over pressure valve was replaced the machine was back in business. Good Luck and let us know how you go.

[MrJack]

Given that it doesn't happen without the PF, the OPV could well be the culprit (if the backpressure to the pump is low, the OPV won't open).

[TC]

I'll go devil's advocate and suggest that it might be worth getting an appropriately qualified tech. to look at it.

Rather than speculate as to what the problem might be, you will probably have a solution in half an hour and you can then concentrate on the coffee