It's here, my Zaffiro is PID'ed thanks to your help

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Frenchman
Posts: 402
Joined: 14 years ago

#1: Post by Frenchman »

Thanks to all here for your help. I thought I would post a few pictures of the installation.

This is the schematic for what I have installed now. I am considering two improvements but want to use the machine as is first: 1/ a small non-SSR relay to turn heating off while brewing (as heating robs the pump of power), and 2/ an override for the steam using the PID's alarm. If I do those I'll post the schematics for both since I have them.



The PID I am using is the Auber Instrument SYLV-1512A and I got an Amico 25A SSR. AC wiring was done using some NTE 600V 105C 16AWG stranded wire, and DC wiring (to the SSR) using similar but anonymous 18AWG wire cut from a roll at my local electronics shop.

I initially decided that I was going to have the PID hidden inside the machine, but then decided that it would be nice to have the possibility to put it outside. Since I wanted this to be reversible (i.e. when I'll get tired at watching that display or tweaking temperature), I drilled a 1/2" hole at the bottom of the stainless pan and fit it with a rubber grommet that left a 1/4" opening for wiring:



After considering a variety of probes and not being able to find one that would fit nicely in my thermal well (which is probably deformed by many years of heating if I trust the shape of my old thermostat's bulb), I settled on sawing off a 7 cm section of the old copper bulb and soldering a T type thermocouple wire inside it. This is the result (soldering not shown as my soldering skills are atrocious; but it works):



I installed the SSR in place of the old thermostat, reusing the backing plate that allowed the thermostat to be screwed in. This allows me to use the machine's chassis as the SSR heat sink. The SSR is installed upside down so I could directly reuse the wiring that was connected to the old thermostat. It is held by only one screw, but the silicon thermal paste I put between the SSR and the mounting bracket adds a bit of tackiness. The whole thing holds just fine.

As one can see on the electrical diagram, took power for the PID from the main on/off switch, which itself is in series with the water tank switch. The result is that the PID is only on when the machine is on, as expected. (One will notice in the picture below that I also ended up taking neutral from the on/off light-I'll edit the schema accordingly but any uninterrupted neutral would have worked). This picture shows how everything ends up looking inside:





The wires exit from the machine's bottom (just like the power cord does) and are routed under the chassis and up in the back. I loosely braided the four power wires (AC and DC) and left the TC wire running along them. I will cover the whole thing with some red braided techflex.



I have not decided if I am going to leave the PID exposed on the top of the machine or put it in a little box. Auber makes a dedicated anodized aluminum box for its 1/32 DIN PIDs which would be perfect if only they had thought of putting the screws in the back or bottom of the case and not right in front!

So voilĂ : a happy PID'ed Zaffiro. I have a pound and a half of freshly roasted Vivace beans to tune it today...



Thanks again for all your help, advice and sharing of your expertise!
LMWDP #712

Frenchman (original poster)
Posts: 402
Joined: 14 years ago

#2: Post by Frenchman (original poster) »

There are a couple things I want to fine tune as far as installation goes:
  1. It is very very easy for the wires to pull out of the PID when it is handled, regardless of how strongly the screws are in. I'd like to not be surprised with a hot 120V wire touching the chassis some day so I am interested in suggestions to make that connection more robust (even in a project box I'm afraid it could become loose). Tiny spade connectors, bent to 90 degrees is my best guess so far. Anyone has a better idea?
  2. The TC wire I found is probably not an insulated wire. While I think that is fine, the sheaths for both conductors as well as the wire itself seem to be made of cotton and not the typical plastic material (see picture below). As a result, it frays like crazy and unravels. This morning (and granted, after many moved of the PID which twisted the conductors) my PID would indicate room temperature only because the sheaths had unraveled enough for the conductors to touch right by the terminal screws. Has someone used that type of wire and found a good way to deal with that issue? Maybe a drop of super glue on the sheath?
Fuzz from the sheath (red for negative, blue for positive). Yes, I find it ironic (and somewhat appropriate) that a picture of the "fuzz" is out of focus. Sorry about that but I know you get the idea.

LMWDP #712

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bostonbuzz
Posts: 1255
Joined: 13 years ago

#3: Post by bostonbuzz »

Looks great. Thanks for posting that wiring diagram, it will certainly help others. Now you need to cut the hole in the front of the machine! Good luck!!!
LMWDP #353

JimG
Posts: 659
Joined: 18 years ago

#4: Post by JimG »

Frenchman wrote:There are a couple things I want to fine tune as far as installation goes:
  1. It is very very easy for the wires to pull out of the PID when it is handled, regardless of how strongly the screws are in. I'd like to not be surprised with a hot 120V wire touching the chassis some day so I am interested in suggestions to make that connection more robust (even in a project box I'm afraid it could become loose). Tiny spade connectors, bent to 90 degrees is my best guess so far. Anyone has a better idea?
  2. The TC wire I found is probably not an insulated wire. While I think that is fine, the sheaths for both conductors as well as the wire itself seem to be made of cotton and not the typical plastic material (see picture below). As a result, it frays like crazy and unravels. This morning (and granted, after many moved of the PID which twisted the conductors) my PID would indicate room temperature only because the sheaths had unraveled enough for the conductors to touch right by the terminal screws. Has someone used that type of wire and found a good way to deal with that issue? Maybe a drop of super glue on the sheath?
Fuzz from the sheath (red for negative, blue for positive). Yes, I find it ironic (and somewhat appropriate) that a picture of the "fuzz" is out of focus. Sorry about that but I know you get the idea.
What kind of clamping device does the controller use for wire terminals? If a socket (good), then wire ferrules work great. If screw clamps (not quite as good, IMO) then a spade terminal is probably your best bet.

The insulation on the TC wire is probably fiberglass. I've used both superglue and epoxy to bind the fibers, but small diameter heat shrink tube works best.

Jim