Carrier 30XW150-400 specifications Service, 5K Thermistor Temperature C vs Resistance, Ring

Table 39B — 5K Thermistor Temperature (°C) vs Resistance

TEMP	RESISTANCE	TEMP	RESISTANCE
(C)	(Ohms)	(C)	(Ohms)
–32	100,260	3	14,026
–31	94,165	4	13,342
–30	88,480	5	12,696
–29	83,170	6	12,085
–28	78,125	7	11,506
–27	73,580	8	10,959
–26	69,250	9	10,441
–25	65,205	10	9,949
–24	61,420	11	9,485
–23	57,875	12	9,044
–22	54,555	13	8,627
–21	51,450	14	8,231
–20	48,536	15	7,855
–19	45,807	16	7,499
–18	43,247	17	7,161
–17	40,845	18	6,840
–16	38,592	19	6,536
–15	38,476	20	6,246
–14	34,489	21	5,971
–13	32,621	22	5,710
–12	30,866	23	5,461
–11	29,216	24	5,225
–10	27,633	25	5,000
–9	26,202	26	4,786
–8	24,827	27	4,583
–7	23,532	28	4,389
–6	22,313	29	4,204
–5	21,163	30	4,028
–4	20,079	31	3,861
–3	19,058	32	3,701
–2	18,094	33	3,549
–1	17,184	34	3,404
0	16,325	35	3,266
1	15,515	36	3,134
2	14,749	37	3,008

a30-4079	O-RING	BRASS NUT 3/8 - 24 FOR
		ASSEMBLY ON BRASS WELL

Fig. 39 — 5K Thermistor

(30RB660036 Thermistor Kit)

TEMP	RESISTANCE		TEMP	RESISTANCE
(C)	(Ohms)		(C)	(Ohms)
38	2,888	73		775
39	2,773	74		747
40	2,663	75		719
41	2,559	76		693
42	2,459	77		669
43	2,363	78		645
44	2,272	79		623
45	2,184	80		602
46	2,101	81		583
47	2,021	82		564
48	1,944	83		547
49	1,871	84		531
50	1,801	85		516
51	1,734	86		502
52	1,670	87		489
53	1,609	88		477
54	1,550	89		466
55	1,493	90		456
56	1,439	91		446
57	1,387	92		436
58	1,337	93		427
59	1,290	94		419
60	1,244	95		410
61	1,200	96		402
62	1,158	97		393
63	1,118	98		385
64	1,079	99		376
65	1,041	100		367
66	1,006	101		357
67	971	102		346
68	938	103		335
69	906	104		324
70	876	105		312
71	836	106		299
72	805		107	285

SERVICE

Economizer Assembly — Each circuit on 30XW175,200,350,400 units has an economizer assembly. The 30XW150,325 units do not have an economizer and have one main electronic expansion valve. The 30XW150,325 units are controlled the same way as units with a separate economizer assembly. See Fig. 42.

6" MINIMUM

CLEARANCE FOR

THERMISTOR

REMOVAL

1/4-18 NPT

a30-4080

1.188 in.

2.315 in.

Electronic Expansion Valve (EXV) — See Fig. 43 for a cutaway view of the EXV. High-pressure liquid refriger- ant enters valve through the top. As refrigerant passes through the orifice, pressure drops and refrigerant changes to a 2-phase condition (liquid and vapor). The electronic expansion valve operates through an electronically controlled activation of a stepper motor. The stepper motor stays in position unless pow- er pulses initiate the two discrete sets of motor stator windings for rotation in either direction. The direction depends on the phase relationship of the power pulses.

The motor directly operates the spindle, which has rotating

Fig. 40 — Dual Leaving Water Thermistor Well

(00PPG000008000A)

	a30-4081
	SENSOR
SEN	TB6
	SEN
	7
	8

Fig. 41 — Typical Remote Space Temperature

Sensor (33ZCT55SPT) Wiring

movements that are transformed into linear motion by the transmission in the cage assembly. The valve cone is a V-port type which includes a positive shut-off when closed.

The large number of steps and long stroke results in very ac- curate control of the refrigerant flow. The stepper motor has ei- ther 4260 (main) or 2785 (economizer) steps.

MAIN EXV CONTROL — Each circuit has a thermistor lo- cated in a well in the discharge line of the compressor (DGT) and another one located in the compressor motor cavity (SGT). Each circuit also has discharge and suction pressure transducer. Discharge and suction pressure as measured by the transducers are converted to saturated temperatures. The main control logic for the EXV uses discharge superheat to control the position of the EXV. The difference between the temperature of the discharge gas and the saturated discharge temperature is the superheat. The EXV module controls the position of the elec- tronic expansion valve stepper motor to maintain the discharge superheat set point.

59