Wiring for a retrofit PID

la marzocco, synesso, simonelli, cimbali etc

Wiring for a retrofit PID

Postby tim on Mon Jun 26, 2006 1:33 pm

Anyone have a good recipe or pictures on how to wire these things on a 1 group lmfb70 semi auto?


I can't figure out the electrical scheme.

Me no brain. :shock:
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Postby nick on Mon Jun 26, 2006 2:05 pm

Tim,

The "traditional" way to do this is with a thermocouple (replacing the brew-boiler thermostat), a PID controller that outputs to a SSR (solid state relay, which is what tells the heating element when to turn on and off).

Here's the wiring diagram (you can thank me later):

Image

There is more to it than just wiring it up. The PID controller needs to be the right kind (with the proper inputs, outputs, etc.), the SSR needs to match the proper voltage and amperage, and you have to have the right thermocouple.

Good luck!
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Postby tim on Mon Jun 26, 2006 2:17 pm

Thanks Nick.
I allready have the drawing, but can someone explain me what to do with it ?

Do I have to get more wires or can I use the ones allready inside the machine ?
If so, where do they come from and where do they go ?

What are the different symbols or drawings on the scheme (especially the rount thing with ears that goes from the heating element to the ssr)?

Do I get rid of the safety switch/fuse on top of the group head or shall I leave it?
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Postby xristrettox on Mon Jun 26, 2006 3:04 pm

You and I are in the same boat Tim. I just recieved a PID and don't know what to do with it, and I certainly don't want to pay a tech an estimated 4-5 hours to hook it up.

If nybody on this board has step-by-step instructions, and wants to give em up, I'll give you a big hug.

here's to hoping.
Billy Wilson
Portland, Oregon
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Postby Mike Gregory on Mon Jun 26, 2006 5:50 pm

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Postby Mike Gregory on Mon Jun 26, 2006 5:54 pm

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Postby nick on Mon Jun 26, 2006 6:28 pm

Good stuff Michael. I was just writing up my own text version. I think with what you shared, plus the following stuff (once edited and complete), you'll all be good to go. You have the reconnecting-the-boiler-heating-element-light thing that my instructions lacked. Thanks for that!

------------

Ok. Here's a quick off-the-top-of-my-head, knowing that you shouldn't believe anything I write here until Barry gives it the thumbs-up.

Nick Cho's PID-a-Linea/FB70 for dummies
By: Nick Cho
For: Lineas and FB70's
For: Dummies
June 26, 2006

Background : The stock thermostat works like a home thermostat: the system cools down, until a piece of metal expands and/or contracts, eventually coming into contact with a lead that tells the heating element to turn on. The temperature rises, and reaches a certain point, when the piece of metal curls away from the lead, breaking the current and causes the temperature to start to fall again. Each cycle can be as long as roughly a minute.

The problem is, this method is fairly primitive and imprecise. When the target temperature is reached, the heat contained in the massive heating element continues to heat the water. This results in a temperature "wave," which is what people are "surfing" when they "temperature surf." A 3EE Linea can experience a +/- 2*C (+/-4*F) wave.

Solution: P.I.D. stands for proportional, integral, and derivative. Basically, "proportional" provides an output proportional to the amount of error (gap between actual and target temp), "integral" provides control over the amount of time the error is there, and "derivative" sort of puts the brakes on P and I and keeps them from trying so hard to do their job that they end up overdoing it (driving up the temp). In our context, P.I.D. provides a tight control over the heating element.

What you'll need:
PID Controller - a popular choice is the Fuji PXR3-RCY1-4V (more on this later)
SSR (solid state relay) - 230 volt, 25-30 amp
Thermocouple - though in theory, you could stick one anywhere, the best spot is probably replacing the stock thermostat. A J-Type tc is common, and that's what we'll use in our example.
High-temperature wire - 1 meter of white stuff (same gauge as you see throughout your machine)

Tools you'll want:
A little flathead screwdriver (you know, the tiny kind... but bigger than the eyeglasses-kind)
A wrench to remove the thermostat and install the thermocouple

The place you can get most of this stuff: http://www.espressoparts.com (check out the new logo!)

Summary of work: replace the thermostat with the thermocouple. The thermocouple tells the PID what temperature it is. The PID tells the SSR when to turn on or off the heating element. The PID and the SSR both need to be hooked up to power. Got it?

Step I : The TC
- Turn off the machine. Unplug the power source, cutoff the water supply, etc. Safety first!
- Remove the top panels of the machine (above the groups, above the boilers)
- Wait for things to cool down a little. Go drink a beer. On second thought, drink some coffee instead.
- Just for piece of mind, you can take a high-resolution photo of the guts of your machine, to use for reference if you want. Take close-up shots of the thermostat, and that thing where all the wires converge near the left-side of the steam boiler.
- Remove the thermostat. Simply unscrew it. If the machine is older, this might be an amazing pain in the ass. If there are parts that need to be disconnected temporarily to get it out, go ahead, but don't forget to put them back the way you found them. Keep in mind, the thermostat is in two pieces. The part that slides in and out isn't all that you need to remove. You have to unscrew the shaft-thing that it slides into.
- Snip-snip the wires that connected to the thermostat close to the thermostat. You can probably re-use these.
- Screw in the TC. Screw it down super tight. You don't want a leak here. (Barry: teflon tape here?)
- Wipe your brow. You did good.

Step 2: The SSR
- As in the diagram, the SSR has four terminals. Two talk to the PID, one goes to power, and one goes to the heating element (through a thermal-limiter switch, on top of one of your groups).
- Hook them up as seen in the diagram. Pretty self-explanatory. For the power-lead, look for where one of the two wires from the thermostat went to the power-block (that thing where all the wires converge near the left side of the boilers).

Step 3: The PID Controller
- Just look closely at the diagram, and you'll see where the wires need to be connected to the PID controller.
From left-to-right (bottom-row of terminals):
1: EMPTY
2: blue from thermocouple
3: red from thermocouple (as the diagram says, if in the end things act screwy, try switching these two leads)
4: terminal 4 on SSR (you'll need some wire)
5: terminal 3 on SSR
6: EMPTY
7: EMPTY
8: neutral-side of power block
9: load (hot) side of power block

- As you can see in the diagram, the "neutral" line is shared with one side of the heating element. Follow the heating element (in your brew boiler, of course) wire to that side of the power-block, and just add it wherever it seems to fit.
- Now you need to mount the PID controller somewhere. Take it from me: if it gets wet, it will fry like an innocent man on death row.

Fire it up.


MORE TO COME (Barry, Scace, or anyone else, feel free to chime in and help):
- Why the Fuji PXR3-RCY1-4V and not another configuration of that PID controller?
- Tuning the PID controller
- How to win the WBC
- etc.
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Postby onocoffee on Mon Jun 26, 2006 7:30 pm

I've got my 2AV completely disassembled and the PID kit parts sprawled across my garage and I'm so glad this topic came up because I started looking at the booklet that came with the Fuji controller and I'm like: "Whaaaa?"

Tim-

That thing that's inline from the SSR to the heating element is the Thermal Limiter. There is one TL for each boiler. The brew boiler TL is usually mounted to the top of the left grouphead.

Also, you will have to obtain new wire because there just isn't enough wire in the machine. Keep in mind that stock LM wire is rated for 200F. This is not the usual wire you find at Radio Shack or your local electronics store (at least not in my area). To err on the side of safety I think it's important to source 200F wire.

For my previous grouphead lighting project and this current one, I sourced the 200F wire at my local appliance parts warehouse. Ask them for range (yes, cooking range) wire and that should take care of things. The ones I got are three strand red, white and black wire but as long as you label them carefully and wire them accordingly, you should be fine.

Of course, I think Nick just used whatever wire was at Radio Shack and his shop hasn't gone up in flames...

In Michael's LM Wiring diagram it specifies Pin Terminals. These can be a bit tricky to obtain and my local electronics emporium doesn't have them. If your local shop doesn't have them Radio Shack does. Just look in their parts bin. They also have the large size European Terminal Blocks that are just Too Factory For Words.

Some things I have been pondering is the placement of the PID pieces. I just don't like locating any of this stuff under the boilers - just seems too ripe for dripping and the frying of electronics (Nick). But if you place the items above the boilers, the heat tends to blow them up (Sanders). I'm working on a solution that will move the pieces away from the boilers while still maintaining a factory look. Hope to have some of those machined relatively soon.

I'll be reassembling the 2AV and installing the PID this week so I'll have additional insight soon.
Jay Caragay

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Postby barry on Mon Jun 26, 2006 8:43 pm

heh-heh-heh....


so, where are you guys actually putting the controllers?


are those spiffy diagrams from EPNW?


--barry "2nd annual espresso technology symposium, july 2, 2007"
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Postby barry on Mon Jun 26, 2006 9:12 pm

nick wrote:- Remove the thermostat. Simply unscrew it. If the machine is older, this might be an amazing pain in the ass. If there are parts that need to be disconnected temporarily to get it out, go ahead, but don't forget to put them back the way you found them. Keep in mind, the thermostat is in two pieces. The part that slides in and out isn't all that you need to remove. You have to unscrew the shaft-thing that it slides into.


"an amazing pain in the ass" can be an understatement. on older machines, the thermostat itself is often scaled/crudded into the thermowell (that "shaft" you mention), making removal quite difficult. the thermowell itself... well... on the last one i did i had to use an impact wrench to free it (yeah, the same thing used to remove lug nuts). make sure you have the correct sized wrench. i don't recall what it is, but it is big and metric and not cheap.


Screw in the TC. Screw it down super tight. You don't want a leak here. (Barry: teflon tape here?)


teflon tape may or may not help. the threads on the thermowell are parallel, not tapered. the seal is achieved using the copper crush washer (you *do* have a new crush washer, don't you?). again, the last time i did one i had to use an impact wrench to get it seated enough that it wouldn't leak.
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Postby tim on Mon Jun 26, 2006 9:20 pm

Thanks a million !!!!!!!!!!!!!!!!!!

Love you guys, I can't thank you enough.

I just woke up in the morning a bit frustrated and the first thing you know is that my friends at coffeed made my day !

I am skipping breakfast and heading down to my nearest el-store. They better be open....

Grazie mille !
Tim Wendelboe
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Postby onocoffee on Tue Jun 27, 2006 2:43 am

The PITA for me has been removing the steam boiler element. I'm way past frustration and am well into anger/revenge.

After a couple failed attempts, I left the boiler soaking in a very high concentration citric acid bath. For four days. Thought that would do the trick and the boiler would come out clean. Upon inspection through the holes, I could see that the boiler walls were nice and clean but the heating element was still crusted with black scale. Bitch!

I've twisted, hammered, sprayed WD-40, sprayed on gasket remover in an attempt to eat away the gasket and loosen the element, I've hit it with a torch and I've tried drilling out the sucker - all to no avail.

This morning I'm taking it to a local machine shop where I'm going to have them machine the element out of the boiler.

Oh yes, La Marzocco Steam Boiler Heating Element, you will die today....



.
Jay Caragay

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Postby barry on Tue Jun 27, 2006 7:37 am

HEAT.

apply a MAPP torch to the mounting boss. you don't have to get it really hot, just hot enough for it to expand a wee bit and break the scale seal.

my home machine was bought off ebay with a broken brew boiler, the result of someone trying to force a stuck element. i hit the mounting boss with a torch, put it in a vice and easily unscrewed the element. then i took the boiler and boss up to the local welding shop and they brazed it back on for $15. :)


--barry "how i got a 2-group marzocco for under $1000"
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Postby onocoffee on Mon Jul 17, 2006 9:38 pm

Thought I would throw out this tip that I found today when I realized that I didn't have enough copper crush washers to do two machines (I only had one).

Went to the local hardware store but they didn't have anything when the guy at the hardware store mentioned that the crush washers were like the ones on cars. That's when it struck me - the crush washer looks to be about the same size as the one that fits the oil pan on my Land Rover Discovery.

A trip to the local dealer confirmed this and for the exorbitant price of $2.84, I picked up an extra crush washer.

So for those of you in need of a copper crush washer to mount your thermocouple probe, ask the local auto parts store (or Land Rover Dealership) for the oil pan crush washer for a 1995 Series I Discovery.


.
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Postby Mike Gregory on Tue Jul 18, 2006 12:02 am

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Postby onocoffee on Tue Jul 18, 2006 3:50 am

Did you install the probe in your steam boiler? Because the upper half of the standard LM gauge only reads the steam boiler pressure and not the brew boiler pressure.

The probe I installed replaced the thermowell in the brew boiler.

And since I've got an air compressor in my garage, I hit that with the impact wrench to seat it - a la Barry Jarrett.
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Postby Mike Gregory on Tue Jul 18, 2006 10:30 am

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Postby barry on Wed Jul 19, 2006 11:47 am

the probe fitting might have a gasket mounted to it. a lot of BSPP fittings come that way, so you might not have even noticed it. a BSPP fitting will NOT seal on the threads alone, unlike most US pipe fittings (which use a tapered thread).
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