We have an elderly Gaggia Classic - bought secondhand nigh on 20 years ago, doing daily service.
Yesterday the pour got quite slow. This morning it was non existent.
I have a blind basket with a pressure gauge on - its not getting above 4 bar (OPV is set to 9)
I've backflushed it, then descaled it (not normally an issue with our water). Done the usual rattling of buttons, and even had the solenoid to pieces - no obvious issues. Water and steam appears when and where they should.
Now with a blind basket in, the Over Pressure Valve (first thing in the chain after the pump) isn't blowing off and dumping water back into the tank, so that says to me the pump isn't generating enough pressure - ergo new pump needed. Would others agree with that diagnosis?
Thanks!
Water is dumped into the tray with a blind basket, at least on mine?! I thought the other tube in the tank was for expansion water.
You'd hear it if pressure was anywhere near high enough though so it'd be obvious.
I'm no expert but would agree it's a low pressure issue from what you've said
I'm off to see my daughter tomorrow. They have on long term loan one of my 3 Classics. It's normal when I get there that it's a bit (or very) constipated. I always have my miniature socket set with me when I go, together with a Philips screwdriver, pliers and some open ended spanners.
It's about a 20 minute job to remove the lid, undo the pump and pipe, get in and remove the solenoid, take that apart to expose the bit with the 2 ports and jiggle about with a bit of fuse wire to clear the blockage. You expect to see a chunk of calcium but never do. Give it a little blow before and after to see if you've made a difference.
Reassemble and pull a lovely shot. I keep meaning to take photos to put on the last thing you mended but I never do.
If you suspect the pump, undo the hose and see what happens.
@BigJohn - as above I pulled the solenoid off yesterday, stripped it and blew the various orifices through with the compressor - no change.
@kamikaze - My understanding is that the solenoid dumps the brew head pressure into the drip tray when you stop brewing, to depressurise the brew head before removing the portafilter.
The OPV, which is directly after the pump, governs the pressure limit that gets applied to the brew head before that. This has an overflow back into the tank (the outlet is a little nipple in the “roof” of the tank. With a blind basket in, the pump should (and usually does) make enough pressure to flow water back into the tank, but it isn’t …
I’ve also just disconnected the pump and run it into a cup.
It’s moving water, but very sputtery.
I don’t have any feel what kind of flow an unrestricted vibe pump should have though, so not sure what it tells me! Should it be gushing through?
You probably have, but have you cleaned the mesh thing that's sits in the brew head? It's directly above where the basket goes in, fixes with a single screw in the centre.
And then unscrew the two bolts and lever off the aluminium block. Prepare to be horrified at the amount of solidified coffee that you can scrape off to make a channel for the water to flow along.