GS/3 Coffee Boiler Temperature Adjustment

[chasr]

Many new GS/3 owners are confused by the Coffee Boiler Temperature Offset adjustment and rightly so. It's definitely counter intuitive.

First, let me preface the discussion by saying that LaMarzocco sets the temperature offset at the factory. It should not be necessary to change the Offset value. If you decide to anyway, ensure that you have an instrument such as the Scace II and a high quality digital thermometer which supports a "T" type thermocouple. (LaMarzocco actually claims to use instrumentation more accurate that the Scace II for their factory adjustment.)

There are three components to obtaining the desired water temperature:
1) The Coffee Boiler temperature setting
2) The Coffee Temperature Offset
3) The front panel temperature display

The front panel display is a calculated setting based on Coffee Boiler Temperature setting plus the Offset. The Coffee Boiler temperature setting actually sets the temperature of the water inside the boiler. In spite of the saturated group design, there is a temperature loss between the coffee boiler temperature sensor and the water temperature exiting the group. The offset corrects for this difference and should always a negative number. The ramification of this design to the user is that when you want to set a particular temperature, you need to know the offset which can be viewed as one of the "Machine Off" programming mode parameters. Then the user has to "do the math".

Example: I want to set the group water temperature to 201.1F(*) and I know that my offset is -3.4F. I set the Coffee Boiler Temperature to 204.5F and the result is that the display reads 201.1F which perfectly agrees with the temperature of the water exiting the group since the offset is properly set.

To say it in a different way, the Coffee Temperature Offset is used so that the display temperature matches the water temperature exiting the group. However, the side effect of using this offset method means that the coffee boiler temperature must be set to a value equal to the desired water temperature with the offset added to it. It would have been a MUCH smarter design to be able to program the desired group water temperature and have the machine do the math and set the boiler temperature higher by the offset automatically. For the price of this machine one would be right to expect this level of automation, but it's not there!

(*) The LM GS/3 can only be set in 0.3F increments so 201.1F is as close as I can set the temperature on my machine given the required offset.