# PIDing the Gaggia the cheap way



## alekk (Feb 24, 2013)

Hi all,

I have just acquired a beautiful Gaggia classic and I am thinking of fitting a PID. I think that I have understood the basic principles behind the operation and how this needs to be done (thanks to the many forum posts). Nevertheless, I don't think that I will buy the rather expensive Auber kit but instead will get the parts on ebay -- it seems like one can do pretty much the same thing for less than half the price. One thing that I am slightly worried about is the tuning of the PID controller. How hard is it in practice to teach the PID to control the boiler's temperature. Do all PID have an autotune function, and if so how efficient is it?

Cheers!


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## Callum_T (Dec 23, 2012)

alekk said:


> Hi all,
> 
> I have just acquired a beautiful Gaggia classic and I am thinking of fitting a PID. I think that I have understood the basic principles behind the operation and how this needs to be done (thanks to the many forum posts). Nevertheless, I don't think that I will buy the rather expensive Auber kit but instead will get the parts on ebay -- it seems like one can do pretty much the same thing for less than half the price. One thing that I am slightly worried about is the tuning of the PID controller. How hard is it in practice to teach the PID to control the boiler's temperature. Do all PID have an autotune function, and if so how efficient is it?
> 
> Cheers!


I don't think you'll be able to get the eBay ones to learn the temp drop like the auberins ones, but with good k type thermocouple there's no reason you won't be able to get a decent improvement in temp stability. When I owned my classic I was weighing up a ghetto dual steam and brew temp control PID but I just couldn't justify the price.

If I remember thought there wasn't a proper "ghetto eBay pid" walk through specific to the classic so I guess it would get use if someone had the spare time and the knowhow.

I remember a forum member really raving about the official auberins PID being worth the extra money though (was it shrink?)

Auberins will add quite abit of resale value if you were to ever upgrade so as most things you'd have to look at the auber as an investment rather than the means to an end with a compromise which the eBay ones might be.


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## tribs (Feb 21, 2012)

All the cheap ebay PIDs I've looked at have the Autotune function. The Auberins version is pretty much the same unit, except it has been preprogrammed and comes in a nice little kit including a case. The difference in cost is quite large and the difference in function is quite small. The main problem I have with the Auberins PID is it still uses the original thermostat location, which in my opinion is poorly located.


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## alekk (Feb 24, 2013)

OK, I have just installed the Auberins PID on my new Gaggia! Works perfectly but have not tried yet to get a proper espresso shot (am still waiting the non pressurised baskets).



tribs said:


> The main problem I have with the Auberins PID is it still uses the original thermostat location, which in my opinion is poorly located.


That's funny because I was coming to the forum to ask precisely this question. The location of the brew water thermostat is very far from optimal - I would say that it is the worst location. We are basically reading the temperature of the resistances. I was thinking of exchanging the steam/brew thermostat (one needs to extend one wire) and plug the PID on the steam thermostat. Anybody has done that before? Does it give better results? Any better option?


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## Jez W (Jul 2, 2012)

alekk said:


> OK, The location of the brew water thermostat is very far from optimal - I would say that it is the worst location. We are basically reading the temperature of the resistances. I was thinking of exchanging the steam/brew thermostat (one needs to extend one wire) and plug the PID on the steam thermostat. Anybody has done that before? Does it give better results? Any better option?


I agree that the default location for the thermostats means that you are sensing the temperature of elements rather than the water temperature. I moved my thermocouple as close to the brew head and as far away from the elements. ie right down the bottom front of the boiler. The location for the steam thermostat is on a spur away from the boiler so I thought it was better to place it next to the brew head, this seems to work well for my Sestos PID. One advantage of having a small boiler like the gaggia is that if you wait for the temperature to become stable on pid then after a few minutes you know that the water temperature inside the boiler will be the same as your pid reading. Both Aluminium and water are good thermal conductors.


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## bronc (Dec 10, 2012)

@Jez W how did you attach the thermocouple to the boiler?


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## Jez W (Jul 2, 2012)

I just used a large Jubilee clip to hold the thermocouple in place at the base of the boiler.


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