The Watlow SD3C is a digital temperature controller that displays both current temperature and set point - but is still the 1/32 DIN size that fits MLG's smallest stainless steel enclosure (same as the 935 series). Click here for detailed users' manual from the manufacturer. This controller can be used on both 110V and 220V systems, both in the US and internationally.

This may be the perfect controller for adding a PID to Silvia. It offers a 2-line display with the capability of simultaneously showing set point and current temperature. This is Watlow's current state-of-the-art single loop controller - and carries a full 3-year manufacturer's warranty. And, it fits in a 1/32 DIN size enclosure! So if the larger size of MLG's other 2-line display controllers is an issue for you, then the new SD3C line of kits may be the answer.

Based on the testing we have done to date with this controller, we are very impressed. Previously, among the Watlow controllers offered by MLG, the Series 93 and 965 controllers had provided both the most stable setpoint control at idle, and the best recovery from pulling a shot. But the SD3 seems to outperform them both. Take a look here at some real data showing impressive performance by this controller on a brand new Silvia.

In addition, Watlow has apparently made some improvements in the thermocouple circuitry with this line of controllers. Our distilled water ice bath tests gave results that were nearly perfect, and our testing at high temperature showed similar excellent accuracy as compared with a very accurate digital thermometer.

In short, we are very excited about the SD3 controllers!

Experiments have shown that temperature 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 called Rancilio 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. This stock thermostat permits more than a 40F range in boiler temperature. Some experts 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 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) :

• Randy G's PID page - Me Be PID
• Murph's page - popular guide for DIY installation
• Dave Bennett's page - internal PID installation and temperature graphs
• A Tail About Silvia - a novel approach, using a flexible goose neck.