Single Boiler PID Upgrade

[Stine]

I came across the PID Upgrade for the Rancilio Silvia (which as far as I understand is a single boiler).

My question is, can any single boiler machine be upgraded with a PID unit?
If yes, does anyone have general schematics / guides / how to ?

P.S. the upgrade is mean for a Fiorenzato Colombina I recently purchased. Although I can't find a lot of information online about the machine, so far I know it uses 3 thermostats to keep the temperature within range, and its a Single Boiler E61.

 

[Musicphan]

Yes - the Silvia is a single boiler. And yes, I guess in theory you could put a PID controller in any unit. You are simply replacing the thermostat with the PID controller. However, I think the schematics of the machine and PID controllers would be necessary. That's the extent of my knowledge

 

[Stine]

I am trying to contact official resellers to gather the schematics, but it really seems a long reach... the company itself deals mostly in commercial equipment, and despite being 2019, I couldn't find an official website (the existing one lists only grinders).

However, while I try to gather info and decide whether the upgrade is worth it, I ordered a group head thermometer.
Even if its not as accurate and controlled as a PID, I can surf until I find the sweet spot right?

 

[Musicphan]

1st Line carries that brand. If its got multiple thermostats its probably pretty temp stable already. What are you trying to gain from adding the PID? The Silvia is a bit different being a single boiler and poor stability... that's why people started adding PID's.

 

[Stine]

I emailed 1st line and currently waiting for a response. On their technical data section there is nothing for the colombina specifically, but I thought I'd try contacting them.

With regards to thermal stability, today I received the E61 Temp sensor, and yes the machine has pretty good stability on 205F at the group head on idle or brewing mode, but once the pump engages it goes up to 210F before going down to 200. I still have to quantify the volume required to go down.

The PID was a technical curiosity and the opportunity to brew (possibly better) some single origin beans that are hard to extract.

 

[Stine]

My research for diagrams regarding the machine is still inconclusive...

However, today I was curious to verify the claims regarding the Colombina not having an adjustable Expansion Valve (OPV)... When I disassembled the opv during the cleaning process I noticed a notch that suggested regulation was possible, and I was right, the OPV is in fact adjustable. It was set to 16 Bar (basically inoperative) which required a flawless grind, distribution and tamp (and sadly I don't have tools and technique strong enough to achieve that yet). Now that I set it to the proper 9 Bar (diy portafilter measuring device is now in production to double check lol) I am pulling much better shots on average.

At this point, between the ability to regulate pressure and the group head temperature sensor to surf, I have a lot of control (and IMHO no real need for a PID upgrade)... any thoughts and suggestions?

 

[Musicphan]

You may want to dig into the 16 bar standard... that seems odd that it would be set that high since industry standard identifies 9 bar's as optimal. Next time I run into my espresso tech I'll see if he has any thoughts.

 

[Stine]

I purchased the machine second hand, so I don't know if the previous owner adjusted it (tho I don't think so, as the opv screw was so clogged with scale that it was impossible to get regulated prior to a deep clean).

And as far as I understand, grind size, distribution and tamp determine the brew pressure (I was able to pull maybe 2 or 3 very good shots with no channeling and brew pressure spot on 9 bar, before setting the opv).

 

[Musicphan]

How are you measuring pressure - just off the machine or do you have a Scace device?

 

[Stine]

I am relying on the machine gauge until I finish assembling the portafilter gauge.
I set the machine to 10.5 Bar, so in theory I get 9 Bar for brewing (accounting for the loss of E61 groups).
I tried to verify the return flow from the opv (WLL suggests 1 Oz of water in 12 s) and I thought something was wrong since the output was double that (2 Oz in 12 s), but after doing some research, it just means the water pump is strong.

 

[Stine]

Status Update: after the Gicar Box in my Fiorenzato Colombina (2006) broke down, and it seems impossible to find a replacement (Cod. 9.1.40.57), I decided to rewire the machine and install an Auber PID controller, an RTD sensor replacing one of the Thermostats, and an SSR.


I have the machine stripped to the bone, and all the components ready to go.

The components list is the following:


Power Switch
Power Light
Steam Switch (With light)
Water Switch (With Light)
Safety Thermostat
Brew Thermostat
RTD Sensor
PID Controller
Heating Element
E61 Brew Switch
Ulka Pump
Reservoir Tank Switch

Re-wiring the machine sounded appealing to clean up the wiring and approach it as minimalist as possible.
I use the machine exclusively for espresso and hot water, I never use the steam function, so the auto-refill for the boiler is not essential (I ensure the boiler is filled to the top when I turn on and before turning off the machine.

The original Siemens Contactor Relay (which I supposed to be faulty alongside the Gicar Box) is fully functional. Good thing, I'll have it as a backup since it can't be bought anywhere anymore, and the new circuit with the PID controller and SSR makes no use of this.

The Gicar box is back as well, fixed as best as we could. The issue was the 120-12v transformer. We were not able to buy the single component, so we adapted a different power supply for the 12v circuit. However I decided not to use the Gicar Box either, but if I ever need/decide to revert the machine back to stock, the components and wiring needed is all there ready to go.


Now back to the actual project:

-Even though I could use the mounts from the Siemens Contactor, the location was too close to the boiler and up high in the machine frame, so I decided to drill 2 holes and fit the SSR behind the pump, as far away from the boiler as possible.
Installed the silicon mat to help dissipate heat, and secured it in place.

-I also made temporary pump supports to try and lower the vibrations (ideally allowing more movement to the rubber mounts by eliminating the L shape, and swapping it for a solid L shaped metal support). if the concept works, I'll make better looking mounts.

-The RTD sensor has been secured in place of the lowest thermostat. So now I really need to start wiring.
I decided to keep the PID controller external (as I don't want to cut the front and side panels of the machine, so I'll just fix it to the bottom front of the frame and have the cables exit through the window to access the boiler heater.


Searching for previous attempts to PID this machine I came across this: https://rolfb.ch/2014/vitudurum-v2-umbau/
It includes a detailed circuit on how to wire the machine, and as far as I can tell, the components are the same.

However It turns out that the circuit needed some adjustments, so I drew it out specific to this machine, and added a ground for the PID controller as well.

Once I double checked it, I made the wiring from scratch, using cable rated at around 390 degrees, brass female spade crimps, heat shrink insulation, and that was that.

Now I have to figure out the parameters for the PID. does anyone have some reference point for an E61 0.8L boiler?

 

[PinkRose]

Hello Stine,

Wow! That was the best progress report post that I've ever seen posted here on the Coffee Forums.

Thanks for taking the time to give us so much information. I'm sure a lot of people will find your photos and descriptions to be very helpful - for years to come!

~ Rose

 

[Stine]

Thank you Rose, hopefully this will make someone's life easier eventually.

BTW hold on because upon first attempt to turn the water switch on, something shorted and the wall outlet fuse jumped.
So now I am trying to figure out if my circuit is wrong, or if my "translation" from paper to cable is to blame...

I'll keep the updates going.

 

[Stine]

So it seems I added an unnecessary connection from the - Main Switch to the + in of the W (Water) switch, and that's why it shorted.
Its now time for testing, so to make sure the boiler is full before plugging in the machine, I primed the new water pump (which also needed a fair bit of adjustments on the pump supports, to fit without touching anything) and run it until water came out the steam arm and the brew head. shut the steam valve off, then the brew head, allowed the pump to run up to full pressure (which went high up to 15bar with this new pump, while the old one pushed 9 bar with this OPV setting... curious) and the shut it off, and opened the steam valve to relieve pressure.

Its all ready for testing!

 

[Stine]

Staus Update: Understanding how to operate the Auber PID Controller was easier than I thought, once I got past the learned helplessness approach :lol:
I managed to set the proper input and output, and the machine heated properly, so I decided to do a final deep cleaning of the internal components with a water and citric acid solution.

Unfortunately I wasn't considerate enough to protect the pid controller from steam and possibly water droplets (I was still working on its enclosure at the time), I assumed being under the machine was enough, but midway through the descaling process, the controller display was showing U.U . PID #1 down.


P.S. Meanwhile I received the IMS 200 Nano Quartz reinforced shower screen, which just looks so cool, and I am curious to try it out a bit more long term...

While I wait for a new 1/32 Din controller to arrive, I couldn't resist and I ordered a 1/16 din MYPIN PID controller from amazon (ahh the beauty of same day delivery ) wired it up, figured out the parameters and how to operate this temporary controller, and back to testing. (This time I wrapped the controller in clear plastic, so it stays protected temporarily)

As of now I am not worrying too much about fine tuning, since the final controller will be different, but I am taking notes of temperature ranges and differences between the PV from the boiler, and the E61 Group Head Thermometer value, which usually is about 6-8 degree C lower.


Right now the SV is 98.5 C at the boiler, which translates to 90 at the brew head during shots. I will try to gather more data, but what temperature setting do you guys use (single or double boiler PID machine owners) ?