PID Silvia temperature stability thoughts

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Compass Coffee
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#1: Post by Compass Coffee »

I had thought Silvia was rather temperature unstable when doing multiple back to back shots. My measurements showed about 15f difference between PID reading from boiler and grouphead from idle. Series of shots differential decreased and stabilizes at 8f difference from about shot 10 onward.

After playing with the GS3 yesterday and discussing its grouphead heating configuration which is rock solid idle versus series of shots, thinking about E61 and it's design which will have overheated grouphead from idle then stable in series of shots and Silvia and other passively heated groupheads understanding finally occurred. It's not that the PID Silvia is unstable or "overheats" doing a series of shots, it just that passively heating the grouphead requires about 10 2oz pulls coming back up to temp between each pull to get the grouphead stabilized! Duh. Call me slow.

So it of course simply means if just pulling a single shot PID needs to be set differently than if planning to pull a half dozen back to back shots entertaining and when doing a bunch of back to back shots after resetting PID 8f lower than for an idle shot pull 10 2oz blanks before starting the series of real shots. Then those 6 or 10 or whatever back to back shots will be relatively intershot temp stable. It only took me almost 4 years with Miss Silvia for the light bulb to turn on! :oops:
Mike McGinness, Head Bean (Owner/Roast Master)
http://www.CompassCoffeeRoasting.com

Abe Carmeli
Team HB

#2: Post by Abe Carmeli »

Compass Coffee wrote:"Life's Too Short To Drink Bad Coffee"
Life's too short to pull 10 blank shots in order to get a decent cup of coffee. :wink:
Abe Carmeli

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#3: Post by Compass Coffee » replying to Abe Carmeli »

I don't disagree! But it's a work around when entertaining until A) the GS3 is released to market and B) I've saved enough to buy it! :wink:

BTW, my recently finished first cup of the morning Kube's Estate Kona Americano (going to pull a cap in a sec), which was a single double pull, didn't require those 10 blanks shots, those are only needed when pulling back to back shots. YMMV of coure.
Mike McGinness, Head Bean (Owner/Roast Master)
http://www.CompassCoffeeRoasting.com

Abe Carmeli
Team HB

#4: Post by Abe Carmeli »

Compass Coffee wrote:I don't disagree! But it's a work around when entertaining until A) the GS3 is released to market and B) I've saved enough to buy it! :wink:
Just teasing you, of course. An upgrade is forever sweeter when you've earned it. Catering to the whims of a Silvia for so many years most definitely puts you in the sweeter category.
Abe Carmeli

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AndyS

#5: Post by AndyS »

Compass Coffee wrote: It's not that the PID Silvia is unstable or "overheats" doing a series of shots, it just that passively heating the grouphead requires about 10 2oz pulls coming back up to temp between each pull to get the grouphead stabilized!
Hence the logic of actively heating Silvia's grouphead.
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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#6: Post by Compass Coffee » replying to AndyS »

Ok I'll bite. I've heard of it being done but have no idea how! Any place you can point me to? While I'm asking, anyone mod'd their Silvia with active pressure adj instead washer? (have mine currently washer sanded tuned to 8.5bar, was 7.5 before sanding)
Mike McGinness, Head Bean (Owner/Roast Master)
http://www.CompassCoffeeRoasting.com

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AndyS

#7: Post by AndyS »

Compass Coffee wrote:Ok I'll bite. I've heard of it being done but have no idea how! Any place you can point me to?
This is not an installation for the faint of heart. Here's a link to my original post about it on alt.coffee:
http://groups.google.co.in/group/alt.co ... 0fc4d1bf39

Here's a picture of the rope heater before it was puttied in place on top of Silvia's group:


Image
Compass Coffee wrote: While I'm asking, anyone mod'd their Silvia with active pressure adj instead washer? (have mine currently washer sanded tuned to 8.5bar, was 7.5 before sanding)
Some people have added rotary pumps, which allow easy pressure adjustment. Others are working on more sophisticated digital pressure control.
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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#8: Post by Compass Coffee »

Thanks Andy. I'm likely nuts enough to work on the grouphead pre-heater mod. I don't think I'll go as far as external rotary pump, more likely stay vibe until GS3 or ? ....
Mike McGinness, Head Bean (Owner/Roast Master)
http://www.CompassCoffeeRoasting.com

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AndyS

#9: Post by AndyS »

Compass Coffee wrote:Thanks Andy. I'm likely nuts enough to work on the grouphead pre-heater mod. I don't think I'll go as far as external rotary pump, more likely stay vibe until GS3 or ? ....
Also, since you're that nuts, you should preheat the boiler inlet water.
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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#10: Post by Compass Coffee »

AndyS wrote:
Also, since you're that nuts, you should preheat the boiler inlet water.
Yeah, I fully realize the benefit. Especially since seeing how the GS3 HXing the boiler feed from the steam boiler works so well. You using same type PID'd electric heater as for grouphead?
Mike McGinness, Head Bean (Owner/Roast Master)
http://www.CompassCoffeeRoasting.com