Auber PID temperature drop

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BaristaBro

#1: Post by BaristaBro »

I have bought a 2nd handed Rancilio Silvia V1 that came with an installed Auber PID. The thing I notice is that, say I set the temperature to 95°C, once I take a shot the temperature easily goes down to the 82°C range. Is that normal for an (Auber) PID? I had expected it to remain at 95°C whether shooting or not. Is that an incorrect assumption?

JRising
Team HB

#2: Post by JRising »

Is it somehow warming the incoming water to somewhere near 95? Usually it'd need a second boiler, or thermoblock to do that.

If it has only the one boiler, like a stock Silvia, then the cold water going in is going to lower the temperature of the water in the boiler, the cooler water will conduct heat out of the brass and the PID's temp sensor will register that, the display will show the temperature of that spot on the boiler's surface (adjusted by the offset if used).

BaristaBro (original poster)

#3: Post by BaristaBro (original poster) »

Hey JRising, thank you for your answer.

I do believe it has only the stock boiler, without the insulation. Am I correct in assuming this has a significant effect on espresso quality? I just started, but am having some problem pulling decent shots. Could this be a big factor in that?

gscace

#4: Post by gscace replying to BaristaBro »

It's been a very long time since I fooled around with Silvias, but I recall that there is a standpipe inside the boiler that makes it so cold water entering the boiler doesn't mix with what is going to the group. Consequently the temperature remains relatively constant for the brew cycle. It's good to remember that the temperature the PID is measuring is the temperature precisely where the probe is placed. That doesn't mean that temperature elsewhere in the machine is the same.
-Greg

robmack

#5: Post by robmack »

It's possible that the PID settings are not allowing the boiler to recover quick enough to the inrush of cold water from the reservoir. I have a PID on my Gaggia Classic and don't encounter the symptoms you describe. Mind you, the boiler in the Gaggia is much smaller than in the Rancilio. What are your PID settings in Menu 0036?
- Robert

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baldheadracing
Team HB

#6: Post by baldheadracing »

BaristaBro wrote:I have bought a 2nd handed Rancilio Silvia V1 that came with an installed Auber PID. The thing I notice is that, say I set the temperature to 95°C, once I take a shot the temperature easily goes down to the 82°C range. Is that normal for an (Auber) PID? I had expected it to remain at 95°C whether shooting or not. Is that an incorrect assumption?
Yes, it is normal in an early V1. Early V1's have a thermowell cast into the boiler housing and Auber uses an RTD with these early V1 boilers. These two features allow for both rapid response and more precision (although the latter is somewhat excessive for coffee). The thermowell is close to the water intake so you see the effect of fresh water entering the boiler.

In other words, you're seeing what actually happens - at the thermowell. That is not telling you what is happening to the brew water temperature - which will only decline by 0.5°C or so during a shot.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

BaristaBro (original poster)

#7: Post by BaristaBro (original poster) »

@robmack you're going to have to help me there. The PID came pre-installed with my second-hand Silvia. I basically have no idea how it works :oops: :lol:

robmack

#8: Post by robmack »

My experience is with a Gaggia Classic and a XT7100 PID. The Rancilio Silvia and the Aubers PID are going to be different but it might help to know what your current control settings are. I would recommend going to the Auber Instrument website to locate the user manual for your PID model, download it and read the procedure for getting to the Control Settings menu (usually "0036") to display the values. You don't want to change them; just record the current values. This is the menu that will show you "P", "I", "d", "Souf", "ot" and "FILE" parameters.
- Robert

BaristaBro (original poster)

#9: Post by BaristaBro (original poster) »

@robmack I took a look at the 0036 settings:
  • P = 2.0
  • I = 60
  • d = 15
  • SouF = 0.2
  • ot = 2
  • FILt = 0
These settings were configured by the guy I bought the machine from second-handed.

Does this give any hints on whether or not the temperature is something bad or not necessarily?

robmack

#10: Post by robmack »

Thanks for getting that information. The values programmed into your PID are extremely close to the ones I'm using on my PID-enabled Gaggia Classic. So, I'd say there is nothing about the setup of your Aubers PID that would be contributing to your problem. I'm not familiar enough with the Rancilio to feel confident in offering other avenues of investigation. The advice you've gotten from others in this thread is pretty good.
- Robert