MLG Properties
Rancilio Silvia PID Kit Review
PID for the Masses
by Randy Glass - Copyright 2006 - All rights reserved

     When it comes to coffee, like any other specialty food product, there is seemingly no end to information on ways to make it better. With any given method of making coffee there are a set of parameters that apply- fresh-roasted coffee, properly ground, quality water heated to a specific range of temperature, a ratio of water:coffee, and an amount of time that the coffee contacts the water. They are all important. Each has a range, some wider than others, and there is always a subjective element to where those parameters lie, but still, the range is fairly narrow. Unlike beef, few like their coffee "rare" or "well done" but everyone likes their coffee done well.
     We spend a lot of time, effort, and money trying to control those parameters to the greatest extent our bank accounts will allow. When it comes to espresso, water temperature is a critical parameter, and up until recently it's one that many manufacturers, even those makers of commercial machines, have overlooked. When it comes to home machines it has been fairly well ignored. It was known for some time how important it was, but the ability to accurately control it was out of reach of the masses. That all changed with the early experiments done by Andy Schecter and Greg Scace. For details see the following posts on Usenet (Use Google Groups Search, or the links below):
Tricked-out Silvia
Andy Schecter Feb 4 2001, 12:43 am
Temperature study of my Sylvia (looong)
Greg Scace Feb 5 2001, 12:50 pm
     How important is temperature control when making espresso? Many home barristas with minimum experience in making espresso state that they can taste a difference as small as one or two degrees Fahrenheit in the set temperature. Some experienced users say they can taste a 0.5 F. degree change.

P I What?
     What is a PID? Very simply, in this instance it is a digital thermostat that replaces the brew thermostat in your espresso machine (or anywhere else, for that matter). It can "learn" the device to which it is connected and adjust itself to the way it works. In the case of an espresso machine, it can adjust itself so that it knows just how long it needs to turn the heating element on or off so that a given set temperature can be reached as quickly as possible without overshooting that set point. It 'pulses' the heating element to first attain and then maintain that temperature. For under $200, or for the resourceful home hobbyist maybe around $100 using some used parts and digging through their parts bins, can add PID control to their espresso machine.
     Those ground-breaking experiments by Andy and Greg mentioned above began a growing group of supporters of the need for brew temp control and set a foundation that proves that temperature control is important for proper espresso and, more importantly, that it can be done fairly easily and affordably. Still, not everyone feels comfortable messing about with electricity, and only some of those folks have the resources as to know where to begin purchasing the correct parts and how to install them. Not everyone knows how to attach wire connectors safely or has the knowledge to read electrical schematics. Without the knowledge or experience it can be hard to know where to start, because the basic PID installation requires:
  • A PID unit and a box in which it is mounted
  • A way to safely mount that box on the espresso machine
  • A Thermocouple to mount on the boiler to sense the temperature
  • A Solid State Relay (SSR) to switch power to the heating element, isolating the PID from the high current
  • Related wires and connectors to connect all these things together and connect to the various electrical points in the machine

    How? "He's" How!
         Although I have had a lot of PID information on my website for quite some time, and the benefits of adding a PID to an espresso machine has been well established, there seemed to be a gap. I was about to begin writing a step-by-step procedure to install a PID (not an easy task as you could imagine) when a post on alerted me to the fact that it already existed! Beyond that, the person who wrote it was selling a complete, ready-to-install kit, with full instructions and every wire, nut, and bolt included.
         It didn't take me long to see the value of that, and so I immediately contacted Jim, the "he" at MLG Propeties who had created the instructions as well as put the entire kit together. We had a really great phone conversation and my invitation to MLG to have their kit reviewed here on "Espresso! My Espresso" was accepted.
         There are various kit options as shown on the MLG website. SIngle and dual line displays, some PIDs come with 3 year warranties, they will install their kit in your own SIlvia and even have PID-equipped Silvias available for sale! Ceckl out the site for what is currently available. Prices start at a reasonable $120 fr the do-it-yourself kit.

          As far as testing goes, all the PIDs are pre-tested and calibrated before being shipped, new and used. MLG offers a 7 day return privilege so if you order it and think that installation is beyond you, just pack it up and send it back for a refund. A minimum 90-day warranty on all parts applies. Check the main MLG webpage for current pricing and availability. You pay actual shipping charges (no handling or packing fees).
         I chose the Watlow 935 kit for its compact size.

    Ooo! It's Here!
         The kit arrived quickly and was very well packed and protected and included what looked like everything needed to install short of the tools and a tiny little electrician. The kit includes:
  • A Watlow 935
  • A custom stainless steel mounting box for the Watlow 935 PID
  • A Solid State Relay
  • Custom Mounting Bracket with Velcro
  • A Thermocouple temperature sensor with a little tube of heat transfer grease
  • Assorted wires, clamps, grommets, cable cover, and other sundry items needed for installation
  • A CD with assembly instruction files in PDF format as follows:
  • The operator manual for the Watlow 935
  • The PID Installation manual (close to 50 pages with lots of photos)
  • A Silvia physical parts diagram with exploded view and part numbers
  • A Silvia electrical parts diagram with exploded view and part numbers

  •      So basically, it appears that you get everything you need except tools and a Silvia espresso machine. I got the kit with the used 935, but I will tell you, I had to examine it very closely to tell it was used. The only clue was that around the edges of the face of the controller some of the plastic was smoothed from being touched. It looked virtually brand new other than it was packed in foam sheeting and not in a Watlow box.

    Tools I Used:

  • Phillips screwdrivers. A short stubby and a longer one will help
  • 7mm socket and extension or deep 7mm socket (this is available on loan to U.S. customers from MLG if you don't have one. Just return it by mail when done)
  • flat-bladed screwdrivers
  • A small, "jeweler's" style flat-blade screwdriver for the small screws on the PID to attach the wires.
  • Small or medium needle nose pliers
  • Wire cutter to trim cable ties
    You Also Might Need:
  • Screw holder/starter for those with big hands
  • Pliers
  • Flashlight
         That list indicates the ease of assembly. The tools I used were the sort of thing you would probably find in even the most austere of toolboxes.

    My Preliminary Comments on the Instructions
         As with all such things, it is best to completely read through the instructions before beginning. I went through them and will supply my preliminary thoughts.
         Half (or more) of the benefit of this kit are the instructions. Getting all the parts together is one thing, and a very helpful one, but installing them safely, effectively, and correctly can be another. This is particularly true for the folks not totally familiar with the internal workings of an electrical appliance.
         I am not going to give all the details of what the instructions include, but will highlight some of the high points I noticed before installing the kit and some final thoughts on its completeness and clarity.
         At the beginning there is a list of the wires included, each being a different color, and fully explained in a chart. Anyone with reading skills and the ability to recognize colors should be able to work that out without difficulty. The entire kit only adds 8 additional wires to Silvia, and that includes the two wires already attached to the thermocouple probe and encased in a sleeve. Could it be that simple? Sure!
         I did find a few minor things in the manual that could be written in a more clear manner, it is only because I have been writing and doing page layout for well over a decade that I noticed. A number of folks have already commented on the thoroughness of the installation guide and how easy it made the installation process, and it is improving all the time, and I have been assured that the areas I noticed will be improved in a short time.
         The installation manual is filled with lots of excellent photos that will make the process easy for most visual learners. The photos are accompanied by the text which explains all the various procedures and gives warnings where they are necessary it makes the process understandable.
         Here is a crop of one image (it was larger than this) and a portion of text from the MLG PID manual (all used here with permission from MLG Properties):

    Once you have located the brew thermostat, carefully work loose the two spade “quick disconnect” electrical connections, as shown.... Patience is rewarded in this operation. Gentle side to side wiggling, along with a slight pulling force away from the thermostat, will usually free these connectors.

         The instructions do warn that the installation of the PID has the potential of voiding the machine's warranty, but I have to assume that reading this far you are not concerned too much with that. Actually, the fact that the PID keeps Silvia at a constant temperature will probably increase the lifespan of a number of parts, and that fact that it eliminates the brew thermostat from the system, one of the very most undependable parts of the machine, makes it an even better idea.
         The nice thing about this kit is that the entire installation procedure and all the parts are specifically designed to make the entire system easy to remove. The installation invloves no holes to drill anywhere and no wires to be cut, spliced, or in any way damaged or changed, neither in the kit nor in Silvia. Just reverse the installation procedure and it is as if the MLG Silvia PID Kit were never installed.

         I installed it in a short afternoon. Including the time it took me to get out to the garage to retrieve tools two or three times and taking a few photos and making notes, I suppose I spent about three hours from the time I put Silvia on the table to the time I plugged it back in. This also included making notes and taking a few pictures. If you are handy, experienced, and more efficient than I am, you might be able to complete it in two hours, but figure three to four hours if you take your time and are detailed oriented. If you are not quite so handy, figure spending a day, with breaks thrown in about every hour or so to relieve the frustration.
         We can divide the assembly into two basic areas- mechanical/physical and electrical.
         The first part of the mechanical/physical portion involves partial disassembly of the Silvia. The top, the back "U-shaped" panel, the front panel over the 3-way valve, and the splash panel under the water tank are removed- a grand total of 11 screws, all clearly explained. Be aware that some older Silvias (about four or more years old) differ slightly from current models so some adjustment to the procedure may be in order for you, but it is a minor difference and mentioned in the manual.
         The second part of the mechanical assembly involves the mounting the hardware:
  • Install the thermocouple on the boiler (one existing screw)
  • Install the SSR behind the front panel (add a supplied nut to an existing screw)
  • Mount the PID in the supplied enclosure
         All of this is explained clearly and sufficiently in the PDF instruction manual in chronological order.

    The Electrical Assembly
         This very well seems to be the easiest part of the entire process! Since all the wires are of different colors, their routing clearly explained, what they do and where they go, all you need to do is take your time and follow the instructions and you should have no problem.

    Parts Quality
         I thoroughly examined all the connectors and how they were attached to the various wires. They all appeared to have been professionally done. All the wires are of very good quality as well. many of the small parts appear to be the same ones I have been using in my machine for years wthout difficulty. Watlow is a major manufacturer and these PIDs should last a good long time.

    Can Anyone Do It?
         No. Not anyone. You have to assess your own ability to do the tasks involved in the installation. MLG told me that if the person has ever changed a wall outlet and feels comfortable doing that, then they probably can install one of their a PID kits. I agree. It is not so much a matter of knowledge of electronics, but being experienced with the use of small hand tools and being able to follow directions. There is no soldering nor any crimping of connectors to the ends of bare wires. Of course, you are dealing with electricity- enough of it to kill you completely dead, so care and knowledge are both good things to have. If you are unsure, either get some knowledgeable help or don't do it.

         The biggest problem I had was removing my old PID installation to install the new one! I had not modified any existing wires, but getting mine out involved cutting the ends off of some of my added wires- something that the planning by MLG will make unnecessary if you decide to remove your PID.
         The only other problem I had was that my plastic insulation sleeves that cover the various spade connectors were very brittle and crumbling. I suggest having some heat shrink tubing or, as the instructions state, replacement insulators on hand if your machine is over about 3 or maybe 4 years old. You may want to examine the insides before ordering to see how many you may need.

         The benefits of such a kit are many:
  • The kit allows those who don't have the time, desire, knowledge, or the resources to purchase and assemble all the correct parts from scratch to have a PID'd machine..
  • If you assemble and install it yourself you will have a greater knowledge about how the machine works so if something goes wrong you have a better chance of fixing it.
  • It saves the hassle, expense, and possible damage of shipping your machine to who-knows-where. Remember that shipping insurance usually only will cover lost parcels or those damaged in accidents, fires, plane crashes, etc.. If it is damaged in transit, virtually by definition, it was not packaged correctly and will not be covered.
  • You can install such a kit in a day or two instead of being without a machine for a week or two.
  • You are sure to get the correct wire gages, connectors that fit right. With all the correct connectors already installed on the wires it saves the DIY'r the trouble of doing that tedious job as well as insuring that all the wires are safely connected.
  • It saves the DIY'er the hassle of trying to find and modify a project box to hold the PID. That alone could be worth the price of admission. I know- BTDT as they say.
  • Finally, the greatest benefit second only to better coffee is the feeling of accomplishment of having done it yourself!

         A lot of thought has gone into this kit and a lot of attention to detail so that it is as easy as possible to install. For example, Even the tips of the various wires where they attach to the PID are soldered so that they do not fray when being routed and attached. It's easy and it works- can't be much "gooder" than that.

    THE BAD-
         Having the manual in digital format can create difficulties. If you have a notebook computer or can work near your desktop, then it is handy. Otherwise you will want to print it out. Of course, it is understandable that the manual is not included in printed form. To print 47 pages, much of it in photographic color, would be prohibitively expensive for a small enterprise such as this, and could easily add $20 to each kit. It's a good excuse to get that laptop computer you have been wanting for so long!

    THE UGLY(?)
         This is a subjective issue. The black and stainless enclosure looks very nice and blends well, but the mounting done with a plastic bracket that is velcro'd to the side of Silvia with the exposed wire harness does not look "factory." Of course, the alternative is to drill holes in Silvia and mount it semi-permanently. There are schools of thought for each variation, but having it mounted in such a way that it can be easily removed leaving no modifications behind has its advantages and, in my opinion, outweighs the minor issues of visual beauty. Check the MLG website for pictures of their units assembled and mounted and decide for yourself. I do not think it is an issue, and the pictures there indicate that, but you have to decide for yourself.       But, you ask, what if I want the installation to be permanent and do not care about holes? Simple. On the side of the enclosure there is an extra 1/2" hole (that doesn't show in the normal mounting solution). You can use a 1/2" nipple and related electrical parts (available in any hardware store but not included in the kit) to mount the enclosure "permanently" to the side of Silvia by drilling a 1/2" hole in the black steel framework on SIlvia between the front and rear stainless stell panels. This eliminates the plasic mount, velcro, and external wire cable. It's your choice.

         Is it worth it? Only you can decide that. If you are one of those handy sorts that seems to be able to accomplish most any such job, have experience, possess a parts-box full of most of the bits and pieces you will need, and you want to save about $40-50 it might make sense to hunt down the parts and work out the assembly on your own. For the rest of us, the MLG kit saves the hours needed to get all the right parts, buy all the wire to create the wiring harness, and fit the PID in an enclosure (just finding an enclosure that works can be time consuming!). Finally, the instruction manual may very well put this kit well over the top. It makes the installation quite simple and understandable and for most people may very well make this the best value in PIDs around.
         Everything you need, all in one kit, with a complete instruction manual with lots of great photographs. If you have been thinking about PID'ing your Silvia, then seriously consider this kit. I think you will be glad you did!