Thinking of adding a PID to Gaggia Classic...

[broz]

I'm thinking about PIDing my Gaggia Classic. I have question to Gaggia PID owners. Does PID make valuable improvement in espresso? I've heard that Gaggia Classic has small boiler so the PID doesn't have much water to keep at a stable temperature.

And what do You think about PIDkits.com ? It's a very good solution for Rancilio Silvia users. May I use it in my equipment? And which modification I have to do to fit "Silvia PID" in Gaggia Classic?

I've read this forum for few months but this is my first post so I would like to say hello to everybody

[Swemarv]

I have a PID on my Classic since 1.5 years now and I am very happy with it.
You will not get stable temperature during shots but you will get consistent
temperature from shot to shot and that is worth the PID in my opinion.
If you want, you can go even further by preheating the incoming water to get
stable temperature during the shot.

I agree that the grinder is much more important but if you have a good grinder
and want to improve the espresso PID is worth it in my opinion.

[broz]

I've got Mini Manual. I spent a lot of time improving my shots. And now I'm still thinking how my espresso could be better. My shots are different and taste different even when I use the same coffee, grind the same amount of beans, use constant tamp pressure and use the same setting in my grinder. In my opinion it's caused by temperature.

Swemarv, what kind of changes in espresso taste do you see when you started using PID? And how do you preheat incoming water?

[JonS]

And what do You think about PIDkits.com ? It's a very good solution for Rancilio Silvia users. May I use it in my equipment? And which modification I have to do to fit "Silvia PID" in Gaggia Classic?

I've dealt with Jim at PIDKits.com before. I didn't buy one of his kits, but bought a surplus PID, SSR and thermocouple from him via eBay. He's a great guy to deal with, and although his kits are targetted at Silvia, he does have some knowledge of the Classic and how it differs from the Silvia in terms of his kit.

Having said that, fitting a PID is pretty straightforward electrically, but there's a reasonable amount of work involved in doing it, and you need to be reasonably savvy to take either the bare parts or a kit for another machine and adapt it.

I did originally buy the parts from Jim with the intention of PIDing my Classic, but I got a really good deal on an Isomac Zaffiro and ended up buying that and fitting the PID to it instead. The Classic isn't a difficult machine to work on however. You need a slightly different thermocouple washer to the Silvia, and there's less room to locate the SSR in the Classic, otherwise, I think they're pretty similar in terms of the hookup, that's as much as I can tell you myself. PIDing a single boiler machine involves mounting the thermocouple, replacing the electrical connections on the brew thermostat with connections to the output of the SSR, and then wiring the PID to the SSR, the thermocouple to the PID and finding live and neutral taps to power the PID, earth as well if you're using a metal case for the PID.

I would suggest contacting Jim at PIDkits, and seeing if he has any suggestions about adapting one of his kits. I could probably lend a hand from an electrical perspective, seeing as I still have my Classic laying around to refer to, if you get stuck.

Additionally, I would agree with the opinion that a PID will do nothing for temperature stability during the shot. The boiler and group configuration pretty much own that area. It will however allow you to forget temperature surfing and give you consistency over the starting temperature of the shot, which is definitely worth having.

Jon

[jesawdy]

Here's a link to PID installation in a Gaggia Coffee, http://www.domesticbarista.com/content/view/17/27/

[JonS]

Here's a link to PID installation in a Gaggia Coffee, http://www.domesticbarista.com/content/view/17/27/

That's a useful article, but some additional comments:

Be very wary of using "sticky pads" to secure anything inside an espresso machine, due to the high temperatures involved especially when steaming, the adhesive is likely to melt and the SSR fall off and potentially cause some damage. In addition, it's good practice to bolt the SSR to some metal, to act as a heatsink. Using an SSR with a capacity for a much higher current draw than required for the boiler element will reduce the need for highly effective heatsink.

In addition, the choice of wire for the additional connections inside the machine is important, again due to the high temperatures. When I did my Zaffiro, I used high-temperature silicon insulated multi-strand cable, rated for 300 deg C.

Those generic "insulated" crimp terminals aren't great either, frankly. You get a far better crimp connection with the uninsulated plated ones, which you can use with separate insulating boots.

And if you use a metal project box to house the PID, be sure to earth it.

If you're going to throw down the cash for a PID I think it's worth doing properly. When I did my Zaffiro, it took me ~30 mins to wire it all up, and then several weeks of thinking about how best to integrate it with the machine to make a quality job that would be safe to use, and would last a long time. Others may not be aiming so high, but it pays to ensure that the changes you make are at least safe and unlikely to start a fire or give off toxic fumes when things start melting or fall off

Jon

[Swemarv]

Swemarv, what kind of changes in espresso taste do you see when you started using PID? And how do you preheat incoming water?

I get consistent shots, thats the biggest advantage. And I can tune the temperature to match the blend.

The preheating is described in this thread
http://www.home-barista.com/forum...classic-t2794.html

[deggy]

Be very wary of using "sticky pads" to secure anything inside an espresso machine, due to the high temperatures involved especially when steaming, the adhesive is likely to melt and the SSR fall off and potentially cause some damage. In addition, it's good practice to bolt the SSR to some metal, to act as a heatsink. Using an SSR with a capacity for a much higher current draw than required for the boiler element will reduce the need for highly effective heatsink.

Re the sticky pads - that's true for the cheapo ones you get on strips down at Staples, but the ones that I used are fairly expensive 3M pads, 1 inch square and believe me, they aren't budging! To ensure a perfect bond it's also advisable to wipe the attachment point with rubbing alcohol first to make sure it's clean.

As for the temperatures reached by an SSR, you are correct when dealing with a smaller amperage SSR in the 110v market, and I should have mentioned it in the article, it's important for people using smaller SSRs to use a heat sink, particularly when dealing with a current at 110v. However, at 240 volts the SSR becomes far less hot (something about voltage, current and work, but it's been a long time since I looked at the physics!) and as I use a 40 amp unit too I have no problems with heat generation, as far as I have checked the SSR never becomes hotter that the ambient temperature inside the espresso machine, and that's after being on for a few hours.

In addition, the choice of wire for the additional connections inside the machine is important, again due to the high temperatures. When I did my Zaffiro, I used high-temperature silicon insulated multi-strand cable, rated for 300 deg C.

I agree that this would have been the ideal solution, but I don't think that the stuff I used was unfit for purpose - it's just good quality multi-core wire, as used elsewhere throughout the machine.

Those generic "insulated" crimp terminals aren't great either, frankly. You get a far better crimp connection with the uninsulated plated ones, which you can use with separate insulating boots.

I agree, the plastic bits on crimps are a pain in the a**e - I remove them, thread them onto the wire, then crimp the bare metal connection and slide the plastic back over for some insulation. I did actually buy some of the nice transparent insulating boots a few months later and they are now installed.

And if you use a metal project box to house the PID, be sure to earth it.

I agree, mine is plastic.

If you're going to throw down the cash for a PID I think it's worth doing properly. When I did my Zaffiro, it took me ~30 mins to wire it all up, and then several weeks of thinking about how best to integrate it with the machine to make a quality job that would be safe to use, and would last a long time. Others may not be aiming so high, but it pays to ensure that the changes you make are at least safe and unlikely to start a fire or give off toxic fumes when things start melting or fall off

Now hang on a minute - 'worth doing properly'? This project took a lot of time to research, I had to draw the schematics from scratch and it certainly took more that ~30mins! Every precaution applicable to the materials and currents I was using was taken and the result is perfectly safe. I took a great deal of time to share the main details with anyone who's interested, so please don't go implying that my result is somehow unsafe and/or incompetent. Yes, I don't go into the details of how to crimp, or how you should consider mounting your particular project box but that is left for a reader - I would make the assumption that anyone who is considering this mod would have to a: Know what a PID is and, b: Think that installing one was feasible and a good use of their time. If someone fits into these categories then I would expect them to be able to judge for themselves what methods to use. And if all else fails, well, they should have read the warning more carefully

Dan

[JonS]

Dan, I guess I must have come across pretty harsh...which wasn't really my intention at all. Really. No way was I trying to diminish your efforts. I think it's great that someone has actually documented a Gaggia Classic PID install.

Now hang on a minute - 'worth doing properly'? This project took a lot of time to research, I had to draw the schematics from scratch and it certainly took more that ~30mins! Every precaution applicable to the materials and currents I was using was taken and the result is perfectly safe. I took a great deal of time to share the main details with anyone who's interested, so please don't go implying that my result is somehow unsafe and/or incompetent. Yes, I don't go into the details of how to crimp, or how you should consider mounting your particular project box but that is left for a reader - I would make the assumption that anyone who is considering this mod would have to a: Know what a PID is and, b: Think that installing one was feasible and a good use of their time. If someone fits into these categories then I would expect them to be able to judge for themselves what methods to use. And if all else fails, well, they should have read the warning more carefully

I guess we come from opposite sides here. Disclaimers are fine, but at what point can folks be sure that they really understand everything involved so they can attempt something like this ?

For me, I think that a lot of folks who consider a PID are certainly doing so because they believe it is a good use of their time, but mainly because they want better espresso. That's really all that matters to them at the end of the day. Most of the folks on this board probably don't have a solid grounding in electronic / electrical installation, and probably know little about how their machines work electrically. A number of the points you've raised here weren't obvious from your article, even though now it's plainly clear now that you thought about them at the time. I just wanted to stress some of the potential problem areas with an install, and it was easiest to do it in the context of the article that had been posted. When people alter their own machines, they're free to do it in any way they see fit, but I don't think it hurts to provide as much info as possible. Folks can pick and choose the bits that work for them. I thought I was adding value to your article, not detracting from it.

In hindsight, "Worth doing properly" was probably an unfortunate choice of words and I do apologise for any offence caused. Like I say, it wasn't my intention.

Jon

[broz]

Thank You very much for all informations. I’ve got one more questions to You.

Where I should put a thermocouple tip? There are a few ways to do that:
1. I can screw it to the surface of the boiler like in “Silvia PID” from pidkits.com
2. I can drill a hole in the boiler and put the thermocouple through that hole
3. I can use some connectors e.g. (thermocouple goes through the screw):

(Dan Gray Mod from domesticbarista.com)

And the last one but I don’t understand it well:
4. I can replace a brew thermostat to another one with some modifications

(pravspresso from HB)

Which modification will be the best in Your opinion, most effective and easy to assemble?

[deggy]

Thank You very much for all informations. I've got one more questions to You.

Where I should put a thermocouple tip? There are a few ways to do that:
1. I can screw it to the surface of the boiler like in "Silvia PID" from pidkits.com
2. I can drill a hole in the boiler and put the thermocouple through that hole
3. I can use some connectors e.g. (thermocouple goes through the screw):

It's a little hard to see this from my images I admit - tricky to get a camera in there to where i've mounted it! Don't drill a hole in the boiler - it develops a high pressure when you're in 'steam mode'. You can surface mount if you like, and most people do, but I couldn't find a reliable schematic of the boilers internal structure and so couldn't be sure if i'd find an area with a representative measurement of the water temperature (as opposed to an area with a thick area of metal where i'd just be measuring retained heat.) I used the bolt in the thermostat hole because I think that the boiler designer put the thermostat there for a reason.

And the last one but I don't understand it well:
4. I can replace a brew thermostat to another one with some modifications
Which modification will be the best in Your opinion, most effective and easy to assemble?

Replacing the boiler thermostat with a more accurate one can be done but the factory installed ones are of pretty good quality and I think you could end up spending a lot for very little gain.

I still maintain that my bolt-with-a-hole mounting the thermocouple at the bottom of the original thermostat hole is the best solution to the problem.

[JimG]

Deggy -

How did you drill the hole through the 4M bolt? What kind of setup did you use?

Jim

[deggy]

Deggy -

How did you drill the hole through the 4M bolt? What kind of setup did you use?

Jim

Ideally you'd use a drill press, but I don't own one. A hand-held power drill is far too hard to control accurately to get an accurate hole - in the end I just used a standard metalwork bit and a hand drill - I think I got the bolt I used on the second try. Only took a few minutes.

[dsc]

Hi,

Deggy:

how did you seal the hole in the screw after placing the thermocouple in?

Cheers,
dsc.

[deggy]

Hi,

Deggy:

how did you seal the hole in the screw after placing the thermocouple in?

Cheers,
dsc.

I didn't seal it - if I had I wouldn't have been able to rotate the bolt to mount it in the boiler with the thermocouple wire through it (not easily, anyway). The thermocouple is not attached to the bolt at all - the function of the bolt is just to provide the pinch between the welded thermocouple end and the base of the old thermostat pit.