7–35 T-354Due 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 muchhigher or lower than the resistance values given.7.23.2 Sensor Replacement1. Turn unit power OFF and disconnect power supply.2. For two wire sensors, cut cable 5cm (2 inches) from shoulder of defective sensor and discard the defectivesensor only. For 3-wire sensors, cut at 23cm (9 inches). Slide the cap and grommet off well mounted sensorand save for possible reuse. Do not cut the grommet.3. If required, prepare the replacement sensor by cut ting sensor wire(s) back 40mm (1-1/2 inch). For 3-wiresensors, the black wire should be cut at the middle length and the red/white wire cut to the shorter length(See Figure 7.29).4. Prepare the cables by cutting wires to the opposite of the sensor (See Figure 7.28).When installing a single wire color two wire sensor, cut one wire of existing two wire cable 40 mm (1-1/2inch) shorter than the other wire.When replacing two single sensors with a combination (3-wire) sensor, the black wires of the cables shouldbe cut to the same length and the red wire of one cable cut to the shorter length.When replacing a original 3-wire sensor, cut the black wire to the middle length and the red wire to theshorter length.Figure 7.28 Sensor and Cable SpliceTable 7–1 Sensor Temperature/Resistance ChartTemperature (C) Temperature (F) Resistance (Ohms)RRS, RTS, SRS and STS:0 32 32,650 +/-9125 77 10,000 +/-50AMBS and DTS0 32 32,650 + 1720- 162025 77 10,000 + 450- 430SensorCablesHeat Shrink Tubing Large Heat Shrink TubingREPLACEMENT 2--WIRE TO 2--WIRE OR 3--WIRE TO 3--WIREREPLACEMENT FOR DUAL, SINGLE SENSOR CONFIGURATIONREDBLACKRED/WHITECableSensor
