View Full Version : PID thoughts?

11-07-10, 07:47
Can anyone here speak to the before-and-after different made by PID-ing a basic home machine? In my case it would be a Gaggia Classic, but I imagine the results of doing the same to a Sylvia would be relevant enough to help me make a decision.

For the last week or so every shot from my Classic has pulled very sour. Today I measured the temperature of water in the basket as around 154F or 68C, which strikes me as awfully cool even given the imperfections of my test methodology (fully warmed-up portafilter loosened after a final brief flush and then held right under the shower screen with a continuous-reading IR thermometer pointed into it while the pump is actuated). I will do some more tests tomorrow (testing temperatures and shot flavour after switching to steam temperature for various numbers of seconds), but I suspect I may need a new thermostat.

A replacement thermostat is priced at 20, but a full PID kit is available for 100. Given that I'll need to spend some money and then get inside the machine and do some fiddling about in any case, the PID option has acquired an immediacy for me that it has not had before. But before dropping an extra 80 on it I'm curious what experiences others have had.

(In my case the PID kit would be shipped to my USA address for pickup when I'm there in a few weeks, so international shipping issues ought to be irrelevant.)

Thanks for any input any of you might have.

11-07-10, 08:09
I was off down the PID route but unfortunately the one I ordered from Auber Instruments in Georgia never arrived, they refunded the money as I got cold feet about having another one sent and it vanishing too. I still may give it a go but will likely go for a self build from components sourced in the UK once I have got the wiring sussed. Others have done it for around 50.

Lucky you to have a Stateside address which will solve the International shipping and possible taxation. Annoying thing is, last time I was in the States, I drove through Alpharetta where Auber are based but not going back anytime soon unfortunately.

Good luck with PIDing, looks like your Gaggia is in need of some thermostatic loving.


11-07-10, 09:36
I, too, was thinking about a PID but decided against it as it would invalidate my warranty. A PID is something I would want for my next machine so I would be looking for one that is already built in.

11-07-10, 11:42
First step would be to sort out the thermostat.

I have used 2 PID'd Gaggia Classics and the results are noticeably different than the standard model. Temperature surfing is no longer required. The Gaggia Classics have a variable temperature range and a fairly long recycle time between shots

Another option might be to sell the Gaggia Classic and upgrade to a Rancilio Silvia. Much more temperature stable and probably attainable within budget too

12-07-10, 07:42
Thanks, Glenn. When you say the results are noticeably different, may I take it that you mean they are different in a good way? Not needing to temperature surf would of course be a substantial win in itself.

12-07-10, 08:55
Yes, in a very good way. The ability to get water at the temp you want is a huge benefit.

Consider the 120c thermostat which will allow you to get closer to 100c and maintain the temp when the PID is installed

Member gaggiamanualservice should be able to sort you out with one for a self install

12-07-10, 09:31
I guess I've gotten confused. I had thought the PID replaced the thermostat, with the PID temperature sensor going into the spot where the thermostat would normally mount. If in fact both are needed, then I may just stick with the thermostat for now.

FWIW this is the unit I had in mind: http://www.auberins.com/index.php?main_page=product_info&products_id=35

12-07-10, 06:14
Correspondence with the PID kit manufacturer indicates the PID takes over the thermostat's role entirely, so I expect to go the PID route in a few weeks, and will make do with a wonky thermostat until then.

12-07-10, 07:39
You are right about the thermostat, the Gaggia one is bypassed and replaced with a thermocouple which the PID uses to control an SSR(solid state relay) which handles the switching of the power to the boiler heating element. Total of three main components plus cables, spade connectors and some thermal paste.

Mostly I have been investigating home brewed PIDs online this week.


12-07-10, 07:43
Thanks both for the updates

I've got a spare Gaggia Classic in full working order that I am keen to mod
Will see what your PID is like before ordering

12-07-10, 08:15
Dad, I am in New York at the end of the year and wondered about picking up a pid then, if it were possible, but I did wonder if they would let me on the plane home with something that looks like it may be something else altogether. Guess I'd have to hope a Silvia owner was on security.

13-07-10, 08:11
I'm going for the PID. Won't have it until mid-August when I get back from California. In the meantime, steamswitchsurfing is getting my brew temps into ranges where I can get tolerable shots.

13-07-10, 06:07
If you want to do it sooner (and maybe for cheaper) this (http://www.domesticbarista.com/index.php/Adding_a_PID_to_a_Gaggia_Coffee_espresso_machine.) seems to be a good guide.
The parts are available in the UK, it seems, at similar prices. Just means you'll have to get the bits and pieces yourself. No offence to the Americans....:good:

14-07-10, 08:15
Thanks! Very informative. Though I think I will still go with the kit, as I am doing OK with steamswitchsurfing in the meantime.

Also, knowing me, I am concerned about what may happen if I go the true DIY route. "Why use a stock PID when I could write my own LCDuino (http://www.amb.org/audio/lcduino1/) code instead? Oh, and store profiles for each blend I like! Hmm, I wonder if I can PWM (http://en.wikipedia.org/wiki/Pulse-width_modulation) the pump motor to give me a pressure profile. Could I build an HTM (http://www.numenta.com/about-numenta/numenta-technology.php) to detect blonding?" Before long I'd be adding Tesla coils and flying kites in thunderstorms to give my espresso LIIIIIIIIIIIFE!! and then the mobs with pitchforks and torches would come. Best if I keep it simple with the prebuilt kit. But thanks again for the link, which I am keeping for future reference. :)

11-12-10, 02:56
I ordered a PID kit from Auber for my Gaggia Classic and it arrived (in the UK) in less than a week with no import duty to pay. Very straightforward to install and use. Highly recommended.

19-12-10, 11:25
When I had my Silvia I added a to PID her and it made a world of difference, no more temp surfing and it also beefed up the steaming capability of Silvia, well worth the effort.
got the PID from Jim at:-
great installation instructional CD, all wiring colour coded, took about 1 hour to install