Troubleshooting; Component And Check Points; Thermistor Characteristic Graph; Fan Motor - Mitsubishi City Multi PEFY-P72NMHSU-E Technical & Service Manual

[8] Troubleshooting

1. Check methods

1. Component and check points

(1) Thermistor
Room temperature thermistor (TH21)
Liquid pipe thermistor (TH22)
Gas pipe thermistor (TH23)
Disconnect the connector and measure the resistance between terminals with a tester.
(Ambient temperature 50°F (10°C) - 86°F (30°C))
Normal
4.3kΩ - 9.6kΩ
(Refer to the thermistor characteristic graph below.)

1) Thermistor characteristic graph

Low-temperature thermistor
Room temperature thermistor (TH21)
Liquid pipe thermistor (TH22)
Gas pipe thermistor (TH23)
Thermistor R = 15 kΩ 3%
0
Multiplier of B = 3480 kΩ 2%
Rt = 15 exp { 3480(
32°F (0°C) 15kΩ
50°F (10°C) 9.6kΩ
68°F (20°C) 6.3kΩ
77°F (25°C) 5.2kΩ
86°F (30°C) 4.3kΩ
104°F (40°C) 3.0kΩ
(A) Temperature
(B) Resistance

(2) Fan motor

Refer to the page on "DC fan motor (fan motor/INV board)."(page 47)
(3) Linear expansion valve
Refer to the page on "LEV". ([8] 4)(page 51)
HWE10170
Abnormal
Open or short
1 1
) }
273+t 273
°F (°C)
(kΩ)
50
40
30
20
10
0
-20 -10 0 10 20
(A)
- 13 - 13
30 40 50
GB