I love my Silvia - why do I need a PID?
Experiments have shown that
is one of the most important factors to control
when making espresso. Even small temperature deviations away from optimal can have an adverse affect on taste.
With its heavy brass construction, the Rancilio Silvia (sometimes incorrectly called Sylvia)
espresso machine is capable of temperature
stability and control that rivals costly heat exchanger machines.
Unfortunately, a new Silvia is not configured to take full advantage of those capabilities and
comes to you with an inexpensive bimetallic thermostat.
stock thermostat permits more than a 40F range
in boiler temperature.
Many professionals and advanced amateurs believe that
espresso quality is affected by temperature variations of less than 1F.
Wouldn't it be nice to virtually eliminate brew temperature from the list of variables that
stand between you and repeatable "perfect" shots?
Luckily it is possible to take full advantage of Silvia's capacity for stable brew temperatures.
With a straightforward modification you can control Silvia's boiler temperature to within approximately
1F. The key components of this modification include:
- a digital electronic temperature controller (commonly referred to as a PID),
- a solid state relay (SSR) to quickly and silently switch the heating element on and off,
- and a thermocouple probe.
The internet has many examples of PID installations on Silvia. Following are a few of them
(these links will open in a new browser window)
Design objectives for our kits
To address the needs of Silvia owners who appreciate the benefits of PID control, but
prefer not to ship her somewhere for surgery, we designed the original Do It Yourself kits with the following objectives in mind:
- high quality industrial temperature controllers (not the inexpensive Chinese-made controllers flooding eBay) should be used;
- the installation should be totally and completely reversible, allowing Silvia to be returned to her exact "factory-new" configuration and appearance;
- the enclosure for the PID should not detract from Silvia's good looks;
- the internal wiring must be UL rated appliance wire, appropriate for the high temperatures inside the machine;
- no drilling or cutting should be required (especially into Silvia);
- it should be installable using nothing more sophisticated than screwdrivers, needle nose pliers, and a socket;
- and it should be complete - no trips to the hardware store.
Features and highlights With MLG's PID installation kits we think we have succeeded in satisfying the above objectives.
Each of our state-of-the-art kits features:
- Custom made, properly grounded, brushed stainless steel enclosure.
This custom enclosure, only available here, has been designed
and fabricated specifically for these kits, with both appearance and function in mind.
(Note: we now can provide crystal clear acrylic mounting brackets for installation on espresso machines
that do not have a black frame. This new bracket looks good on all-stainless machines, like Isomac Venus and others).
- UL listed internal wiring of the proper size and temperature rating, including oversized power wiring through the SSR.
- Proper insulation and shielding of the SSR terminals (to avoid the shock hazard we have seen in some other installations).
- Custom made type T thermocouple probe, using Special Limits of Error (SLE) wire. Others use type K or J thermocouples.
The thermocouples in our kits have less than 1/4 the error limits of standard type K or J probes.
- Rubber grommets at all wiring penetrations to avoid dangerous chafing of insulation.
- A calibrated, tuned, and fully tested PID digital temperature controller, pre-set to 224F or 106C according to customer preference.
(This setting can easily be changed, but is a good average starting point for many espresso blends).
- Premium quality
or other fine quality temperature controller. As noted in our
we offer both
new controllers (still boxed), or refurbished controllers. Whether new or used, each of our controllers
is fully tested and calibrated and will be functioning perfectly when you receive it.
- Solid state relay (SSR) with a current rating of at least 25A. As with controllers,
we offer both new, in box SSR's, or lightly used SSR's. Each will be tested for proper function on a real
Silvia, with the actual controller in your kit, before being shipped to you.
- All required UL listed wiring, color coded, pre-cut to proper lengths, and with terminals pre-installed
- Custom made thermocouple probe (type T, SLE), with high temperature Teflon insulation (there is no fiberglas insulated wire in MLG kits)
- Simple push-on connectors that eliminate the need to cut, strip, or otherwise modify any of Silvia's internal wiring
- All screws, nuts, washers, wire ties, grommets, clamps, cable loom, and other misc. pieces required for installation (We'll even lend you a 7mm socket if you need one)
- Specially fabricated acrylic bracket for mounting PID to Silvia (no new holes of any kind required in Silvia - neither through stainless panels nor through black iron frame)
- Custom designed and built stainless steel enclosure with black acrylic top and bottom panels
- Detailed 40-plus page installation guide, with dozens of color photographs (provided in PDF format on CD)
- 7-day money back guarantee. If, after reviewing instructions you decide this project isn't for you, return it to us for refund of purchase price (less shipping charges).
- 90-day warranty from MLG on the entire kit.
Return defective parts to us and we will send you replacements, at no charge, within warranty period.
In addition to our warranty, some of our controllers and SSR's also carry a manufacturer's warranty.
- Can MLG kits be used on V1, V2, V3, etc. Silvia models? Yes. None of the changes
made on the Silvia affect the installation of our kits. (Actually, the most significant recent change to the
Silvia that affects brewing! Several years ago when the shroud around the grouphead was changed from metal
to chromed plastic, the grouphead temperature increased by several degrees because of the reduction in heat
losses. A change to our "standard" setpoint (from 228F to 224F) was adequate to compensate for this).
- Can MLG kits be used on 220V/240V Silvia models? Yes. All components, including controller and
SSR, are compatible with both domestic US mains (nominal 115V) and nominal 230V international systems.
Satisfied customers have successfully installed our kits on Silvia's in the US, Europe, Asia, and Australia.
In addition, all controllers sold outside the US will be configured for Celsius operation (unless requested
otherwise by the customer).
- Why do your kits call for external wiring to the enclosure?
Our kits are designed to require no cutting or drilling into Silvia, to require no special tools, and to be
completely reversible if desired for any reason.
But if you have the necessary tools, you can easily drill holes through Silvia's black frame and route the wiring directly,
almost totally concealing it.
- Can I use this kit on a different single boiler espresso machine?
Probably. Your success will be dependent upon your own ability to "translate" the installation guide
from Silvia to your specific machine. For no additional cost, we can make minor changes to the thermocouple
probe and to the wiring terminals, if needed, to help with adaptation to your machine. Our kits have been
successfully installed on various Gaggia machines, LeLit's, and the ECM Botticelli. But we do not provide
installation guides for any machine besides the Silvia.
- Do I need a 2-line display?
No, you don't need a 2-line display, but it is very convenient, especially for folks who don't always use
exactly the same coffee beans. Most PID users eventually are able to tell, by taste, where the best set point is for
each different coffee they brew. So they end up changing set points frequently. On the smaller, more common 1/32 DIN size controllers,
displaying the set point usually requires a button press. Changing the set point requires pressing and holding one
button while the set point is changed by pressing another.
- What about calibration of the controller?
Prior to shipping, we carefully calibrate each controller - whether it is brand new, factory fresh
or previously used. We use a lab quality thermocouple calibrator to ensure that every unit that leaves our shop
is providing temperature readings that are accurate to within 0.5F (or 0.5C). This level of
accuracy is probably not really needed
to control an espresso machine, but we want our customers to have confidence that their controller is indeed
providing accurate temperature control on their machine.
- Why do you use thermocouple sensors? I see other PID systems that use pt100.
Lately, competitors have begun to offer platinum RTD sensors or thermistors that have been "borrowed" from other
industries. These sensors, especially the wire leads, are typically far less durable than
the robust thermocouple sensors in our kits. In many instances these RTD sensors
are attached to massive stainless steel bolts (a design common in the plastic extrusion industry).
Generally, because the delicate sensing element itself must be encased in glass or epoxy, RTD sensors
do not lend themselves well to the direct metal-to-metal contact needed for fast sensing of changing boiler
temperatures. The sensors in our kits are designed and built for this one specific application only!