mguterman Senior Member Joined: 10 Dec 2002 Posts: 24 Location: West Haven, CT Expertise: I live coffee
Espresso: Isomac Amica Grinder: Mazzer Mini Vac Pot: Bodum Drip: Melita single cone Roaster: Hottop
Posted Fri Mar 19, 2004, 10:55am Subject: PID Isomac Single Boiler Machine
I am wondering whether anyone has done a PID conversion on an Isomac Amica or Zaffiro. I have an Amica, and it seems that it would be terrific to be able to dial in the temperature.
korngold Senior Member Joined: 21 Jul 2003 Posts: 628 Location: Des Moines, IA Expertise: I love coffee
Espresso: Rancilio Audrey Grinder: Rancilio Rocky Vac Pot: Bialetti Moka Pot (not vac) Drip: Melitta Clarity Roaster: WE Popcorn Pumper/Poppery I
Posted Fri Mar 19, 2004, 11:42am Subject: Re: PID Isomac Single Boiler Machine
Michael,
It should have the same positive effect that it does on Silvia, and you'll likely need the same materials. Do a google search on "Silvia PID" and you get a bunch of hits. Find "Pepe's Silvia Page" and that should give you a pretty decent parts list.
jim_schulman Senior Member Joined: 19 Dec 2001 Posts: 3,772 Location: Chicago Expertise: I live coffee
Posted Fri Mar 19, 2004, 12:10pm Subject: Re: PID Isomac Single Boiler Machine
In one respect, it should be easier and better than the Silvia. The stock thermostat is a bulb into a well in the boiler as opposed to the Silvia's stick on. Using the well to hold the TC (filled with thermal caulk or heat sink compound) will significantly improve the controller's response speed over a Silvia PID.
On the other hand, the bulb stat is way better already, since it too responds quickly and since it's adjustable. So the control improvement may not be dramatic, although the PID will be easier to set than the stock stat.
mguterman Senior Member Joined: 10 Dec 2002 Posts: 24 Location: West Haven, CT Expertise: I live coffee
Espresso: Isomac Amica Grinder: Mazzer Mini Vac Pot: Bodum Drip: Melita single cone Roaster: Hottop
Posted Fri Mar 19, 2004, 2:37pm Subject: Re: PID Isomac Single Boiler Machine
Thanks. What I am looking for is the ability to easily change temperature between blends. I am very happy with the machine as it is. I would have happily paid Isomac the extra money for a setup that let me dial a specific temperature. I don't mind the experimenting that would go along with matching that temperature to what I wanted at the moment.
dcbrown Senior Member Joined: 13 Jan 2004 Posts: 166 Location: Chicago Expertise: I love coffee
Espresso: PID Zaffiro Grinder: Innova i1d
Posted Fri Mar 19, 2004, 4:11pm Subject: Re: PID Isomac Single Boiler Machine
I think PID would be a good option for those of us whose machines have thermostats with excessive temperature differentials. I'm finding out that accurate and adjustable isn't enough. Maybe I should hold my tongue until I install the replacement thermostat that arrived today, but I'm a little concerned that this may be the "new normal" for the Zaffiro and Amica.
jim_schulman Senior Member Joined: 19 Dec 2001 Posts: 3,772 Location: Chicago Expertise: I live coffee
Posted Fri Mar 19, 2004, 5:59pm Subject: Re: PID Isomac Single Boiler Machine
dcbrown Said:
I think PID would be a good option for those of us whose machines have thermostats with excessive temperature differentials. I'm finding out that accurate and adjustable isn't enough. Maybe I should hold my tongue until I install the replacement thermostat that arrived today, but I'm a little concerned that this may be the "new normal" for the Zaffiro and Amica.
A well working bulb stat will have a 3F to 5F differential, just like a pressure stat, as opposed to the 15F to 20F of the click types. But the model Isomac uses has had a fairly buggy history. It's easy to tell how good it is, even without a temperature guage, a 1 to 2 minute on and off cycle during the idle period is excellent, longer is not so good, 8 to 15 minutes is back in bad old click stat territory.
Some people report, they don't have to temp surf their Zaffiros, since the tstat will cycle a few times during the shot, just like the pressure stat on the Tea/Millenium. Others say they do need to wait for the top of the cycle.
dcbrown Senior Member Joined: 13 Jan 2004 Posts: 166 Location: Chicago Expertise: I love coffee
Espresso: PID Zaffiro Grinder: Innova i1d
Posted Fri Mar 19, 2004, 9:03pm Subject: Re: PID Isomac Single Boiler Machine
Next week I'm ordering the PID stuff!
My new thermostat looks a little different from the original one, but the differential is about the same. I checked before installing it and it has a 10F differential. The capillary tube is a much larger diameter...similar to the one on the pressure gauge.
After installing it I noticed that the boiler overshoots the set value by about 5F giving a total of 15F temperature difference. I timed the cycle at 8 minutes. I can reduce that to about 6 minutes by cycling the power switch on and off so that it doesn't overshoot the setting. I suppose immersing the bulb in some heat conducting goop would help with the overshooting.
I suspect the days of Zaffiros that don't need surfing are over. I never minded temp surfing my old machine. The boiler was so small it didn't take long. The combination of a large boiler and a big differential is unworkable.
Posted Fri Mar 19, 2004, 9:38pm Subject: Re: PID Isomac Single Boiler Machine
The temperature you are measuring is the brew water? How do you measure it?
Maybe there are no Zaffiros that don't need temp surfing. I haven't read any reports about very short idle boiler cycles on Coffeegeek or Alt.coffee (boiler cycle being defined as boiler element on plus off time). There are people who don't temp surf stock Silvias and there are people who don't surf Zaffiros. Of the five Zaffiro reviews on Coffeegeek I don't see any mention of any Zaffiro having a very short idle boiler cycle.
This is part of Mark's Zaffiro review:
"however, the Zaffiro has such a large boiler it takes some time between cycle events, and the cycling is long on its own (I've timed it at as long as 67 seconds)", "if you brew while the boiler is cycling (middle light is on)".
So the 67 seconds is the maximum time the boiler element is on and the time between cycle events (when the boiler is off) is long. Well, long is 9.5 minutes on my Zaffiro.
So there is no short idle boiler cycle.
IMO the Zaffiro is the big brother of the Silvia. It makes much better tasting ristrettos but temp surf is still needed. My Rancilio Audrey (similar to Silvia) has a 300ml boiler and an idle boiler cycle of 10 minutes. My Zaffiro has a 750ml boiler and also an idle boiler cycle of 10 minutes (boiler on for 30 seconds, boiler off for 9.5 minutes). So the Zaffiro has a much smaller thermostat differential but it still needs to be temp surfed.
mguterman Senior Member Joined: 10 Dec 2002 Posts: 24 Location: West Haven, CT Expertise: I live coffee
Espresso: Isomac Amica Grinder: Mazzer Mini Vac Pot: Bodum Drip: Melita single cone Roaster: Hottop
Posted Sat Mar 20, 2004, 5:59am Subject: Re: PID Isomac Single Boiler Machine
I would love to know what you get and how you do the install. This is something I really want to do, but I am truly not handy. I really think that a PID modified Zaffiro or Amica is close to the ultimate for the non milk drinker.
dcbrown Senior Member Joined: 13 Jan 2004 Posts: 166 Location: Chicago Expertise: I love coffee
Espresso: PID Zaffiro Grinder: Innova i1d
Posted Sat Mar 20, 2004, 7:53am Subject: Re: PID Isomac Single Boiler Machine
I would love to know what you get and how you do the install.
I'll refresh this thread with an update. I haven't decided where to put it on the machine yet. I may just order the components and try it "breadboard" style first. I don't want to make any irreversible changes to the machine while its still on warranty.
The temperature you are measuring is the brew water? How do you measure it?
I'll refresh the other thread to answer this. I didn't mean to hijack the PID thread.
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