HomeRoast Digest


Topic: Gaggia mods (2 msgs / 56 lines)
1) From: Jeffrey Pawlan
Dear Bob and list,
  I must finish some other immediate projects and I am also going to add more
equipment to the Gaggia. When I am done, I will create a webpage describing all
the modifications.
Basically, the long term stability is assured by heating the supply water. You
are correct that the small capacity of the Gaggia causes the temp controller to
turn the heaters on 100% very quickly into the pour.
Regards,
Jeffrey Pawlan
re thermocouples:  they must be welded to assure accuracy. The solder will
change the output voltage vs temp. Of course, it depends on what kind of
accuracy you are looking for -- maybe solder is OK for you.

2) From: stereoplegic
just got my SSR in the mail yesterday. almost stayed up all night 
removing brew T-stat and replacing w/ Auber Pt100 RTD (i guess that's a 
more accurate thermocouple), wiring up Auber PID and Fotek 25 amp SSR 
(it really didn't take that long, i just wanted to be ABSOLUTELY sure i 
had the wiring figured out correctly, cutting the slot for PID front 
panel in my project box-a gutted old RF modulator for my TV since it's a 
perfect fit and my new RF modulator has an S-Video connection-took the 
longest, can't be too careful w/ a hobby knife @ 3am). fired it up, 
seemed to be working fine, (way past) time for bed. today, drilled a 
hole for wiring in the back of the Carezza so i could screw the top back 
on, turned it and the PID on and waited an hour for warmup (got 
distracted on eBay). ran some water through steam wand to fill boiler, 
flushed group, pulled shot @ set point of 201... wow, that's a really 
good shot-just a tad bit on the sour side, but still really good start 
to finish. next shot @ 202 set point, even better! not sour, very 
consistent from top to bottom (from what i've read and personal 
experience, stock Gaggias shots have a super-dense heart (the bottom of 
the shot), i'm guessing from wide temp swings due to small boiler). on 
these first two post-PID shots, not so much. Tomorrow i'll try 203, or 
maybe 202.3 (one of the reasons i got the RTD instead of using the 
included K-type thermocouple-can measure 1/10 degrees, the other is that 
the RTD is welded to a 4mm .7 pitch machine screw-fits right in where 
the Gaggia thermostat was mounted). this looks very promising... now to 
try to find time off to work on the aforementioned white aluminum 
housing for Gaggia guts and electric cappucino maker for dual boiler on 
the cheap!


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