Carrier 69NT40-561-300, Руководство по эксплуатации и обслуживанию

Страница: 150 / 174

T-365 7–34
7.25.1 Sensor Checkout Procedure
To verify the accuracy of a temperature sensor:
1. Remove the sensor and place in a 0°C (32°F) ice-water bath. The ice-water bath is prepared by filling an
insulated container (of sufficient size to completely immerse bulb) with ice cubes or chipped ice, then filling
voids between ice with water and agitating until mixture reaches 0°C (32°F) measured on a laboratory ther-
mometer.
2. Start unit and check sensor reading on the control panel. The reading should be 0°C (32°F). If the reading is
correct, reinstall sensor; if it is not, continue with the following.
3. Turn unit OFF and disconnect power supply.
4. Refer to Section 7.24 and remove controller to gain access to the sensor plugs.
5. Using the plug connector marked “EC” that is connected to the back of the controller, locate the sensor wires
(RRS, RTS, SRS, STS, AMBS, DTS, or CPDS as required). Follow those wires to the connector and using
the pins of the plug, measure the resistance. Values are provided in
Table 7–2 and Table 7–3 .
Due to the variations and inaccuracies in ohmmeters, thermometers or other test equipment, a reading
within 2% of the chart value would indicate a good sensor. If a sensor is defective, the resistance reading will
usually be much higher or lower than the resistance values given.