Middleby Marshall PS200 series - Manual (Page 56)

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SECTION 3 - SERVICING COMPONENTS
2. Checking the thermocouple with a DC millivolt meter
It is possible to check that a thermocouple is reading
accurately by using a multimeter set to read DC milli-
volts. At 32°F/0°C the thermocouple should read
0 mVDC. This can be checked by inserting the ther-
mocouple into an ice bath for several minutes. At 72°F/
22°C the reading should be 1.134mVDC.
You can use the chart below by checking the tempera-
ture at the thermocouple’s junction terminals. This is
called the Junction Temperature.
Figure 24 - Thermocouple millivolt readings at various operating and junction temperatures