How to measure the temperature in a Column Heater Module (CHM) - WKB746

OBJECTIVE or GOAL

Measure the temperature of the external column heater known as the Column Heater Module (CHM).

There is no qualification product offering for a column heater module (CHM) controlled via temperature control modules (TCM or TCM2).

There is no published specification for measuring this compartment temperature accuracy.

However, we have guidance on how the temperature performance can be assessed. The customer can base their assessment of instrument performance on this guidance if required.

ENVIRONMENT

• Column Heater Module (CHM) - Waters PN: WAT038040
• Temperature Control Module (TCM)
• Temperature Control Module 2 (TCM2)

PROCEDURE

1. Remove all column hardware from the column heater module when performing thermal assessment.
   The CHM is a conductive device,, therefore the probe tip[ needs to be coated with thermal conductive paste to allow for the best thermal transfer to run the test. If thermal conductive paste is not available then a wider test specification must be applied (see details below).
2. Tape the temperature probe near where the internal probe is located (3 inches from the end away from the tubing and in the middle, 2 inches from side wall).
3. Allow sufficient time for the compartment to reach the set point and to equilibrate. Example equilibration times are:
   • 20 minutes at 50C
   • 40 minutes at 100C
   • 60 minutes at 150C
4. Measure the temperature and determine if this meets the following requirements:
   • If probe is coated in thermal conductive paste:
     +2.0c to -4.0c for set points up to 60.0C
     +2.0c to -6.0c for set points above 60.0C
   • If probe is NOT coated in thermal conductive paste:
     +2.0c to -6.0c for set points up to 60.0C
     +2.0c to -8.0c for set points above 60.0C

ADDITIONAL INFORMATION

Allowable measurement device error must be less than or equal to 1.0c. The specification applied must be widened if measurement devices are less accurate.

If a type K probe is used, allow 2.0c additional for the probe inaccuracy.

Thermal conductive paste is not available as a waters supplied part. However, it can be ordered from various suppliers (one example would be Omega Engineering using PN OT-201-2).