Hach-Lange SIGMA SD900 Refrigerated Sampler and All Weather Refrigerated Sampler User Manual - Manual (Page 84)

82
Maintenance
6.6 Thermal sensor calibration (AWRS only)
6.6.1 Thermal sensor verification
To verify the accuracy of the refrigerator compartment temperature,
which is indicated on the sampler controller display, place a
laboratory grade thermometer into a beaker with 150 mL water into
the right rear corner of the tray, and then close the refrigerator
compartment door.
Allow the refrigerator to run for 6–7 hours. This will make sure the
equilibrium between the temperature in the compartment and the
water in the beaker.
Compare the refrigerator temperature readout on the thermal
control diagnostic screen (select
DIAGNOSTICS>THERMAL
DIAGNOSTICS from the main menu) with the temperature indicated
on the thermometer. If the readings do not agree, it is necessary to
calibrate the Reference Temperature Sensor. This cylindrical
shaped sensor is located in the refrigerated compartment right rear
corner, and is held in place by a clip bracket.
6.6.2 Thermal sensor calibration
Prerequisites:
• Ice bath in a 500 mL beaker, using a 50/50 mix of crushed ice
and water
• Lab grade thermometer
Procedure:
1. Press the POWER button to shut off the sampler controller.
2. Remove pull out tray.
3. Remove the Reference Temperature Sensor (RTS) from the
bracket, and place the beaker/ice bath next to the bracket.
4. Place the sensor and the lab grade thermometer in the
beaker/ice bath.
Figure 38 Desiccant holder
1 Plug 3 O-ring
2 Desiccant tube