Gaggia New Baby: Deconstructed - Page 2

Need help with equipment usage or want to share your latest discovery?
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Postby Jake_G » Sep 04, 2018, 10:18 pm


What's silly is that WLL is the FIRST hit for a Google search of the boiler, but doesn't show up at all for a Google shopping search (which is what I was using). :?:

Thanks again MemPast!

It is indeed a nice build quality, even if the boiler is a bit flimsy.

- Jake


Postby MemPast » Sep 05, 2018, 2:47 am

Good luck:)

I Have never found Google shopping usefull. I think it only shows sponsered results.


Postby AZRich » Sep 05, 2018, 11:11 am

Really nice writeup Jake! I'd second the advice to add a pid or microcontroller. My Classic was recently replaced with a $20 (!) nice older Brugnetti find on craig's list, but I used the Classic daily for about 2 years. The heat element in these little boilers is very poweful, and on mine with the stock brew thermostat, when it came up to operating temp it could power on for 13 secs, then cool back down for up to 5 min's before powering on again for a few sec's! So a really big deadband! For me, spending about $30 adding a basic pid with bare wire TC was well worth it!
“A man's got to know his limitations.”

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Postby Jake_G » Sep 14, 2018, 2:28 pm

New boiler arrived!

While standard shipping was over 50% of the cost of a new boiler and not the quickest, I can't complain one bit about the shopping experience at WLL.

Out with the old:
ImageI remove the group when taking the boiler out because the stand pipe leaves the boiler half-full even when no water exits the group. Separating the boiler from the group in the machine makes a wet mess...

Remove the steam valve, thermostats and thermal fuse retaining clip:
ImageThe 147°C steam thermostat goes on top and has a convenient light red dot on top for easy identification.

In with the new:
ImageI used an HNBR O ring, which is good for 302°F.

Install the steam valve:
ImageTighten the bolts slowly, alternating from side to side until the O ring is compressed into the tapered bore on the boiler. This ensures a good seal and a non-broken steam valve.

Install the thermostats and the thermal fuse retaining clip:
ImageRemember the red dot and to leave the retaining clip loose.

I placed the group back into the machine and secured it after removing the boiler:
ImageDon't forget to tighten the water supply line to the outlet of the OPV. Note the stand pipe in the group that ensures there will always be some water in the boiler unless you boil it dry.

Boiler back on the group:
ImageNo need for any sealant when you have a new boiler flange and a soft O ring. I installed the steam wand at this time, as well.

Secure the thermal fuse:
ImageLay the harness across the boiler and tuck the thermal fuse under the retaining clip. Make sure it's centered under the clip and tighten the screw down snug.

The rest of the wiring falls into place:
ImageThe new boiler positions the contacts for the thermostats in a slightly different location than the old, so the wires lay out a little differently but still reach the right locations without issue.

And back together:


- Jake


Postby DaveB » Sep 14, 2018, 6:03 pm

Well done!

Why no espresso in that cup??
Von meinem iPhone gesendet

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Postby Jake_G » replying to DaveB » Sep 14, 2018, 7:39 pm

I simply had no time!

Also, I already had my espresso this morning and I really didn't need three shots to make it through the day. After getting it put back together I had just enough time to prime the boiler and give it a few heating cycles to check for leaks before jetting out the door to work.

Tomorrow morning I'll time some boiler heating cycles using the routine outlined here and then try a few shots to see where a good temperature can be found. I'm all for PID control, but this little guy is so dead simple and repeatable that it's not hard to time your shots on the heating cycle and get great results if you use a consistent approach.


- Jake

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Postby Jake_G » Sep 15, 2018, 6:51 pm

Don't sweat the details...

Unless, that is, you want to make espresso :wink:

I fired up little baby Gaggia this morning and timed the temperature of the group as I was planning on doing some boiler recovery testing and a few pulls with the thermistor bead resting on the prepped puck to see how the intra-shot temperatures were performing. I made it about 15 minutes into the warm up when I swore the PF handle crept a bit to the left. I grabbed it and gave it a slight tug to the right and "crunch". Ugh. I crushed the thermistor bead on my Taylor thermometer. Not a huge set back as I can get a replacement for a few bucks on Digikey once I ascertain the Beta value. It's a 50k NTC thermistor, in case anyone ever needs to replace theirs...

Anyway, I cleaned everything up and tried a timed approach to temp surfing and figured out I have an 18 second window between element on and element off after purging the group one time to initiate a much shorter heat cycle and then purging again to kick the element on a second time.

Ok. Purge, wait, purge, lock PF in group, set shot glasses on scale, tare scale, and start shot at 9 seconds as a baseline. Got it. So I go dose my usual 16.5g into the Gaggia PF, do a little WDT, give it a quick groom and gentle NSEW tamp and go through the whole process outlined above. I find myself really missing Miss Silvia's hot water button... I press the brew button and wait.

And wait...

Then it dawns on me that I preinfuse for ~20 seconds on my commercial machine, and that 20 seconds of preinfusion requires a very fine grind. I then remember that I haven't yet set the brew pressure on the Baby. Crap. About 2 minutes later, I have 30g accumulated in my shot glasses and I relish in the sweet smell of failure. Oops.

What to do? Remember in the first post when I cracked the OPV loose with it on the bench? There's a reason for that. I popped the spout off the PF, gave the threads a quick wrap of Teflon tape and threaded on my ridiculously oversized brew pressure gauge. I popped the basket out and placed a broccoli rubber band around the basket and dropped it back into to PF to great a seal between the pressure gauge and the basket so it doesn't leak all over everything and locked the whole shooting works in the group. Well over 12 Bar. That helps explain the 2 minute shot. Ugh... Better fix that!

Slide out the tank:
ImageThis reveals the fill port at the back and the OPV port to the right and forward of that.

Find the spot:
ImageWay up in there is the OPV spring adjustment/discharge port. 5mm hex is your friend.

Righty tighty, Lefty loosey
ImageWe want loosey. 2.5 full turns loosey, to be exact.

ImageWe don't do "small" 'round these parts...

But of course this was after ruining a perfect dose of beans, and I'm off to Atlanta for a few days, so it'll be a while till I can try it out yet. Not sure just how much I'll have to coarsen the grind to get a properly timed shot.

Until next time,


- Jake

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Postby Jake_G » Sep 22, 2018, 11:56 am

Pulled a nice shot this morning.
No temp surfing.
No scale under the cup.
Just good old-fashioned flush, lock, pull.


- Jake