Thermistors - All thermistors are identical in their tem- perature vs. resistance performance. Resistance at various temperatures are listed in Tables 15 and 16.
LOCATION - General location of thermistor sensors are shown in Fig. 13.
Cooler Leaving Water Thermistor (Tl) - Tl is located in leaving water nozzle. The probe is immersed directly in the water. All thermistor connections are made through a
Cooler Entering Water Thermistor (T2) - T2 is located in cooler shell in first baffle space near tube bundle. Ther- mistor connection is made through a
Compressor Suction Gas Temperature Thermistors (T7 and T8) - T7 and T8 are located in lead compressor in each circuit in suction passage between motor and cylinders, above oil pump. They are
THERMISTOR REPLACEMENT (Tl , T2, T7, TS) (Com- pressor and Cooler)
Thermistors are installed directly in fluid or refrigerant circuit. Relieve all refrigerant pressure using standard refrigerant practices or drain fluid before removing.
Proceed as follows (see Fig. 15):
To replace sensors Tl, T2, T7 (225,250,280), and T8 (225,250,280)
1. Remove and discard original thermistor and coupling.
IMPORTANT: Do not disassemble new coupling. |
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Install as received. | I |
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2.Apply pipe sealant to
3.Insert new thermistor in coupling body to its full depth. If thermistor bottoms out before full depth is reached, pull thermistor back out I/s in, before tightening packing nut. Hand tighten packing nut to position ferrules, then finish tightening 19’4 turns with a suitable tool. Ferrules are now attached to thermistor which can be withdrawn from coupling for unit servicing.
To replace thermistors T7 and T8
Add a small amount of thermal conductive grease to ther- mistor well. Thermistors are
Pressure Transducers - TW O tvpes of pressure trans- ducers are used on 30G Flotronic’” Ii*chille&: a low pres- sure transducer and a high pressure transducer. The low pressure transducer is identified by a white dot on the body of the transducer, and the high pressure transducer by a red dot. See Fig. 16.
Three pressure transducers are mounted on each lead com- pressor: 2
TROUBLESHOOTING - If transducer is suspected of be- ing faulty, first check supply voltage to transducer. Supply voltage should be 5 vdc + .2 v. If supply voltage is cor- rect, compare pressure reading displayed on keypad and dis- play module against pressure shown on a calibrated pres- sure gage. If the 2 pressure readings are not reasonably close, replace pressure transducer.
TRANSDUCER REPLACEMENT
rTransducers are installed directly in the refrigerant cir- cuit. Relieve all refrigerant pressure using standard re- frigeration practices before removing.
1.Relieve refrigerant pressure using standard refrigeration practices.
2.Disconnect transducer wiring at transducer by pulling up on locking tab while pulling
3.Unscrew transducer from !&in. male flare fitting. When installing new pressure transducer, do not use thread sealer. Thread sealer can plug transducer and render it inoperative.
4.Insert weathertight wiring plug into end of transducer until locking tab snaps in place.
5.Check for refrigerant leaks.
-75”
l/4” SAE FEMALE FLARE
WHITE
RED DOT
SAE - Society of Automotive Engineers
Fig. 16 - Pressure Transducer
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