Mitsubishi Electronics PUY-A24NHA2-BS HOW to Check the Components, Medium temperature thermistor

10-7. HOW TO CHECK THE COMPONENTS

<Thermistor feature chart>

Low temperature thermistors

•Thermistor <Outdoor pipe> (TH3)

•Thermistor <Outdoor 2-phase pipe> (TH6)

•Thermistor <Outdoor> (TH7)

Thermistor R0 = 15k' ± 3%

B constant = 3480 ± 2%

t (:): Rt =15exp{3480(

1

–

1

)}

273+t

273

T (˚F): RT =15exp{3480(

1

–

1

)}

273+(T– 32)/1.8

273

0:[32˚F]

15k'

30:[86˚F]

4.3k'

10:[50˚F]

9.6k'

40:[104˚F]

3.0k'

20:[68˚F] 6.3k'

25:[77˚F] 5.2k'

Medium temperature thermistor

• Thermistor <Heatsink> (TH8)

Thermistor R50 = 17k' ± 2%

B constant = 4170 ± 3%

t (:): Rt =17exp{4170(

1

–

1

)}

273+t

323

T (˚F): RT=17exp{4170(

1

–

1

)}

273+(T– 32)/1.8

323

0:[32˚F]

180k'

25:[77˚F]

50k'

50:[122˚F]

17k'

70:[158˚F]

8k'

90:[194˚F]

4k'

High temperature thermistor

• Thermistor <Discharge> (TH4)

Thermistor R120 = 7.465k' ± 2%

B constant = 4057 ± 2%

t (:): Rt =7.465exp{4057(		1		–	1		)}
		273+t				393
					1			1
T (˚F): RT =7.465exp{4057(								–		)}
			273+(T– 32)/1.8						393
20:[68˚F] 250k'			70:[158˚F]					34k'
30:[86˚F] 160k'			80:[176˚F]					24k'
40:[104˚F] 104k'			90:[194˚F]					17.5k'
50:[122˚F]	70k'		100:[212˚F]					13.0k'
60:[140˚F]	48k'		110:[230˚F]					9.8k'

Resistance (k")

Resistance (k")

	50
	40
(k")	30
Resistance
	20

10

0

200

150

100

50

0

500

400

300

200

100

0

-20 -10 0 10 20 30 40 50 : -4 -14 32 50 68 86 104122 °F

Temperature

25 50 75 100 110 125 :

77122 167 212 230 257 °F Temperature

25	50	75	100	120	:
77	122	167	212	248	°F

Temperature

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