An argument for boiler insulation. - Page 2

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CRCasey (original poster)
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#11: Post by CRCasey (original poster) »

I guess I should jump back into this and say this is with a pressure stat not a PID.

And I did not have data from before I insulated the boiler, but I do have recent timings that are close. The original cycle was about 20 seconds on and about a minute off. The cycle with the insulation on is about 12-15 on and about 1.5 min off.

So the overall power is reduced, and I have to guess that the range of temps that are in the boiler itself is the same, because the pressures are the same.

But if that range translates directly to the HX loop is totally unsure. I figure less power and money out of my pocket is a good enough reason to make the change. If it makes a difference at the head, well then that is just happy or not depending on how you look at head temps.

-Cecil
Black as the devil, hot as hell, pure as an angel, sweet as love-CMdT, LMWDP#244

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gyro
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#12: Post by gyro »

JohnB. wrote:Are you referring specifically to an HX machine? The Speedster boilers are both PID controlled and the steam boiler is insulated.
Well, unless something has changed, thats not entirely true. The first half dozen off the line had a PID on the steam boiler but then Kees thought it was not worth it - who really cares about that level of accuracy for steam? You most likely have an electronic temperature control driving SSRs, but not a PID. If you pop the cover off and the numbers are green - its a PID, red - its not. PID on the brew boiler of course.

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JohnB.
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#13: Post by JohnB. replying to gyro »

No changes, i popped off the cover & the read out is red. Looks just like the brew boiler PID other then color. Dug out the control manuals that Paul sent up & the steam boiler uses a Jumo di 32 "Digital Indicator".
LMWDP 267

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cafeIKE
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#14: Post by cafeIKE »

cannonfodder wrote:While you can put a PID on a HX machine I don't see any real need for it. I believe we obsess over uber flat temp profiles simply because it is one of the few variables that can actually be measured.
A PID does not give an uber flat temp profile. An HX PID may change the temp profile. So it will flush and go vs flush and wait. An HX PID enables walkup shots at consistent temperatures with zero flushing. It's also dead quiet and the heating element should last longer due to less full power heating.
cannonfodder wrote:As Jim mentioned, the arguments I have seen against insulating the brew boiler on a PID machine have to do with the derivative (margin of error) or the D in PID for those not familiar with PID function. You should be able to compensate in the programming of the controller but most suggest not insulating the brew boiler because it hinders the accuracy of the PID.
No it doesn't. Insulation changes the rate at which the boiler loses heat. The accuracy of the PID is determined by the firmware, the installation and the setup parameters. A PID may be setup so the boiler never over shoots at the expense of a longer ramp to set point. Properly setup for pulling a shot or two, the system is minimally perturbed.

As mentioned elsewhere, the P is not for Panacea. A PID is a tool. Full stop.

Billc
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#15: Post by Billc »

The parameters in the PID algorithm may be adjusted so that most any system can remain stable (whatever stable means for you). If the boiler is insulated then you can just change the parameters to make it stable. And this will get you a few shots to be consistent. With the colder water entering the boiler, the state of the boiler is much different that when it is just sitting. If there were no insulation then there would be a greater amount of heat loss. Now, on the GS3 for instance, it was designed so that the heat loss of the brew boiler was very close to that of the heat loss from when the colder water enters the brew boiler (remember that the incoming water is pre-heated). This was designed this way so that when you are pulling many shots the temperature control functions very close to when it is just sitting. Thus the parameters used for the PID algorithm will be very close for both situations. In fact the Parameters for the GS3 are at a midpoint between the 2 situations.

If there were insulation on the GS3 boiler, there would be a case where the temperature control would behave a bit erratic (due to the greater difference between the 2 situations). Probably not too noticeable if you are making 2-3 shots.


Bill C

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AndyS
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#16: Post by AndyS »

gyro wrote:The first half dozen off the line had a PID on the steam boiler but then Kees thought it was not worth it - who really cares about that level of accuracy for steam? You most likely have an electronic temperature control driving SSRs, but not a PID. If you pop the cover off and the numbers are green - its a PID, red - its not. PID on the brew boiler of course.
I can't speak for anyone else's Speedster. But when I popped the cover off mine, the steam boiler was controlled by a Jumo unit identical to the one that controlled the brew boiler. But while the brew boiler was running in PID mode, the steam boiler was running in ON/OFF mode (IIRC, using the alarm output on the Jumo).

Actually, I was thinking of changing it back over to a high D ("nervous") PID mode for two reasons:
1. Heating element lasts longer if the time proportioning intervals are short
2. When idling, every time the steam boiler comes ON, the heating element makes a rustling sound. PID mode would be silent.

OK, OK, point #2 is a fine point, indeed. But it's just such a refined machine, why not make it even a little more refined?
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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gyro
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#17: Post by gyro »

Hi Andy, you must have one of the earlier machines with dual PIDs, nice :D

Mine has the straight temperature controller. You can see the red tucked away inside.



Straight from the horses mouth when I asked about it, best part of a year ago... (I'm sure he won't mind)

"Both controllers are electronic, but the one for the rear steamboiler is no PID, so is slightly less super-accurate. As the steam boiler really doesn't need that high degree in preciseness, this is quite plenty good enough.

The very first batch of Speedster did have PID on both boilers. To check: green lighted display means PID, red is just electronic."

You can also see from the website excerpt...

"Electronic temperature controllers driving solid state relays on both boilers, PID on coffee boiler, no moving parts"

http://www.keesvanderwesten.com/speedster_features.html

Seems most people don't notice this. Mark's review also mentions two PIDs (albeit Fuji!)

Sorry, drifting off topic... although slightly back onto topic, you can see the thin (but effective) steam boiler insulation on the above photo.

Cheers, Chris

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AndyS
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#18: Post by AndyS »

Kees van der Westen wrote:The very first batch of Speedster did have PID on both boilers. To check: green lighted display means PID, red is just electronic.
Hi Chris:

I'll be danged, you're absolutely right!

I've actually used two Speedsters. The first one had the PIDed steam boiler. The second one, which is truly "mine," is a later model with the on/off controller. Thanks for pointing that out!
-AndyS
VST refractometer/filter basket beta tester, no financial interest in the company

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gyro
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#19: Post by gyro »

I just love that 'Dueling Speedsters' photo!

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