Hi everyone, I am doing some tests on my La Marzocco GS / 3 and among them is the temperature in the group / Coffee T. Off set and I am in need of help. With a very simple test (low cost), in an attempt to check the Coffee T. Off set, I would like to know if the temperature that appears in the PID (initial information panel) would have to be the same one found in the water temperature measurement performed through a Type K thermocouple at the exit of the center hole of the disc (without the screen).

What would this test show me as a parameter for the temperature settings of the coffee boiler?

Thanks for the help !!

The offset varies from machine to machine, but usually temperature at the group is 2-6 degrees lower than the set boiler temperature. My offset is -4F.

Note that the GS/3 adds the offset to the measured boiler temperature for the displayed temperature. So, if your offset is -4F and you set 204F as the target boiler temperature, the display will show 200F. That should be the temperature you measure at the group.

Hi Dick, thank you very much for your return. Faced with several readings on the subject here in the Home Barista, I really was hoping to get these parameters before starting the tests. To my surprise, the results were different:
I read the temperature through a Type K thermocouple placed immediately in front of the group water outlet (without the shower screen).
My offset to the coffee boiler was -2.0 C and the temperature shown on the thermocouple was about 2C more than the temperature shown on the panel.
A 1.5 F (positive) boiler offset is shown in the manual, which when converted to Celsius is set to 0.8 C (positive).
Here are the values I found so that the water outlet temperature corresponded to the reading on the panel:

Coffe boiler - 93,0 C
Offset - 1.4 C (positive)
Water Reading - 94.4 C
Panel - 94.4 C

Thanks,

Cristiano Robson.

I've read posts from other owners who have positive offsets, but I don't think it's common.

Hard to imagine how water at the probe location in the boiler could be colder than the water exiting the group. I suspect the positive offset may be due to the probe being out of spec. Rather than replace the probe, LM just compensates for the error by using a positive offset.

I see no reason to worry, as the display matches your measured temperature.

That said, just holding a type-K thermocouple under the stream doesn't accurately measure temperature at the puck. First, you need to use a type-T thermocouple with a meter that supports type-T thermocouples. Second, the flow has to be restricted. The Scace Thermocouple uses a type-T thermocouple and restricts the flow to the same rate as the average puck. But it's expensive.

My recollections is that there are some posts here showing how to get a thermcouple inside a basket for more accurate readings.