As delivered, the Pro 800 is set up to draw water from the reservoir. You can confirm it's correct by checking the rocker switch labeled with a faucet behind the drip tray on the left is in the off position and the stopcock underneath the machine, near the right back corner, is pointing to the left (when facing the machine). In reservoir mode, the onboard vibratory pump fills the boiler. In plumb-in mode, the pump and reservoir fill sensor are disabled and the main's line pressure fills the boiler.
The first time the machine is powered up, it will draw nearly a full tank. Let it heat up for 45+ minutes; you can monitor the steam boiler's progress by watching the pressure gauge on the right, or if you're really curious, the digital readout on the temperature controller behind the drip tray. The grouphead is connected directly to the boiler and heats by conduction.
The green light on the left is the power on indicator; the orange light below it is the water present indicator. The reservoir uses a magnetic float to detect a lower water condition; the orange light will go out when the reservoir needs to be refilled.QUICK OVERVIEW
In order to properly operate the Profitec Pro 800, it helps to have a basic understanding of its design. If you prefer "just tell me what to do" type instructions, skip to the next entry!
The Pro 800 has a single boiler that serves two purposes: It provides steam for steaming milk and it provides brew water for making espresso. Since steam boiler water is heated to over 250°F, you may be wondering how it delivers water at brew temperatures, which are typically around 202°F! The answer lies in the water delivery mechanism and more importantly, the massive brass grouphead. The Pro 800's brew water delivery mechanism is commonly referred to a "dipper". Below is the hydraulics diagram of the Pro 800, courtesy of Profitec Espresso:
The tube shown in orange leading from the boiler to the grouphead is the dipper tube. The water initially leaving the steam boiler is way, way, way-y-y over brew temperature, but along the pathway to the grouphead along the boiler/grouphead bridge, it starts to lose heat. Once it reaches the grouphead, you have the thermal equivalent of egg-meets-bowling-ball. That is, the grouphead idles slightly below brew temperature and tempers the incoming water that's over brew temperature, meeting happily in brew temperature range during the extraction.
This design explains why there's a torrent of hot water and steam when the lever is pulled down without coffee/portafilter in the group. The design by Bosco dates back more than 50 years; a few of its advantages include simplicity, reliability, and when properly tuned as with the Pro 800, ease of use.
Another advantage often overlooked is the simplicity of maintenance: Since there's only one boiler, the water in it is constantly refreshed, whether you're making only espresso or a mix of espresso and cappuccinos/lattes. In contrast, a double boiler has a dedicated steam boiler, so water and dissolved minerals enter and only distilled water in the form of steam exits, leaving the minerals behind. Regularly flushing a double boiler's steam boiler via the water tap and using low TDS water delays the need for descaling measures, but by design, the steam boiler on a double boiler needs regular descaling.
That explains how the Pro 800's brew water temperature
is delivered, but what about brew water pressure
That's the job of the spring in the grouphead; it's compressed when you pull down the lever. When the lever is in its down position, the piston is at the top of the cylinder, exposing the port that leads to the steam boiler. Water is pushed out of the steam boiler via the dipper tube, across the boiler/grouphead bridge, and into the brew chamber. Once the lever is released, the spring pushes the piston downwards, closing off the port to the boiler and forcing out brew temperature water through the coffee/portafilter basket below.
For more details on espresso machine design types, see Espresso Machines 101
(single, double boilers and levers) and Espresso Machines 202