# A few questions about the PID on a Gaggia Classic



## ShaunChris (May 4, 2015)

Hey guys, a few newbie questions so be kind please.

I've searched the web but I can't seem to find the info:

1.) What's the difference between the different PIDs?

I know some companies sell the full PID set with the proper length wires and all, like Auberin, which I understand.

But I'm talking about different PIDs, for example REXC100, or Sestos, etc?

*Is it a case of different manufacturers but same function, essentially?*

2.) If I install a PID, do I still need to wait the 20 minutes to warm up the machine?

Currently with my Gaggia Classic, I wait 20 minutes to warm up the machine before the first shot.

Then I wait two heating cycles before I pull the 2nd shot, then steam my milk.

*20min warmup -> 1st shot -> 2 heating cycles -> 2nd shot -> steam*

With a PID, do these timings change significantly?

Cheers

Shaun


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## timmyjj21 (May 10, 2015)

My understanding is that the PIDs are basically the same. Expensive kits are usually tailored to the specific machine type and may have more features, but the DIY versions will 'learn' the machine it is installed in and perform well.

Im still to install my PID so unsure about warmup periods. I assumed it was a bit quicker between shots, but initially there is still a reasonable lump of metal needing to be heated up.

hopefully someone with more experience will chime is, as I would be interested to know too!


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## NJD1977 (Dec 16, 2014)

1. The PIDS all basically do the same job and have very similar functions. They all have auto-tune functions to "learn" the heating/cooling profile of your particular machine so that they can optimise their P,I and D settings to stabilise temperature as accurately as possible.

2. Yes, you do still need to wait 20mins or so to warm up. All the PID does is replace the thermostat to hold the boiler at a far more accurate known temperature. It also reacts way quicker than the old thermostat to changes in temperature, so the elements kick in a lot quicker when you start a shot or a steaming run, which means you get a little more temperature stability during the function. The good thing about the warm up process is you can see the PID read-out varying during this period, and whilst it's still swinging up/down, you know the boiler isn't stable enough to pull a shot yet. Once it settles down to almost rock solid (within 1 deg C) then you know the boiler and water have equalised to that temperature.


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## MrShades (Jul 29, 2009)

The Auber PID is customised - and only available like that from Auber. It has additional firmware options for steam control (without a 2nd SSR, etc.) and for pre-infusion and shot-timers. They've designed the firmware to apply to espresso machines and then they get a regular PID manufacturer to make them (to their design and with their branding).

Other PIDs (REX C100, MyPin, Sestos, etc.) are generic devices that are designed to control the heating or cooling systems within devices or equipment. They work well in coffee machines, and for brewing beer apparently - and in other applications where it helps to maintain and control temperatures within systems. These PIDs have no additional "coffee" features, such as shot-timers or pre-infusion... but they do the main job (of temp control) in an identical fashion to the Auber units.

All PIDs have a "learning" capability - which is the ability for the PID to learn the heating/cooling parameters for what it's controlling. I'm sure the Auber does, and the others certainly do. It's a simple 10 min programme that you invoke by pressing buttons on the PID normally... however, the Auber devices may have a basic espresso setting pre-configured (which doesn't really benefit you much) whereas the other PIDs will have a generic set of PID parameters which will loosely work, but not very well prior to running the auto-learn process.

As timmyjj21 says, the warm up period of the machine is mainly down to the amount of water, brass and aluminium you have within the essential brew components of a Classic. It takes 15-20 mins for the heat from the boiler elements to properly warm up all of the extra bits of metal etc. within the brew path - and is still the recommended warm-up period, with or without a PID.

So - you won't gain much when it comes to warm-up timing, but the main difference is in KNOWING what temp the boiler (and to an extent the boiler water) is at... so that you remove the guesswork and need to temp surf to pour half-decent shots on a Classic. It can therefore be quicker and easier to actually pour shots - and the steam can be made more powerful than standard, so you can have greater steam power (which could speed up your milky drink prep time).

However - the main reason that people install a PID in a classic is to better control the brew water temperature, and thereby minimise one of the (many) variables involved in the process of extracting a decent shot of espresso from a handful of crushed coffee beans.


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