Table 10 — 40QN Thermistor Properties*
TEMP
(F)
MINIMUM
OHMS
NOMINAL
OHMS
MAXIMUM
OHMS
MINIMUM
THERMISTOR
VOLTS — DC
NOMINAL
THERMISTOR
VOLTS — DC
MAXIMUM
THERMISTOR
VOLTS — DC
−40
303,300
342,700
386,200
4.80
4.82
4.84
−30
211,500
237,276
265,444
4.72
4.75
4.77
−20
149,721
166,689
185,146
4.61
4.65
4.68
−10
107,379
118,776
130,973
4.48
4.52
4.55
0
77,281
85,677
93,867
4.30
4.35
4.40
10
56,567
62,617
68,205
4.09
4.16
4.21
20
42,661
46,302
50,129
3.86
3.92
3.98
30
32,043
34,580
37,220
3.59
3.66
3.72
32
30,300
32,550
35,120
3.53
3.60
3.66
40
24,061
26,118
27,960
3.28
3.36
3.43
50
18,650
19,900
21,180
2.99
3.05
3.11
60
14,402
15,312
16,219
2.67
2.73
2.79
70
11,247
11,883
12,518
2.36
2.42
2.47
80
8,820
9,299
9,779
2.06
2.11
2.16
90
6,846
7,339
7,754
1.76
1.83
1.88
100
5,487
5,829
6,187
1.52
1.57
1.63
110
4,367
4,667
4,976
1.29
1.34
1.40
120
3,502
3,760
4,026
1.09
1.14
1.19
130
2,830
3,051
3,281
0.92
0.97
1.02
140
2,300
2,489
2,687
0.77
0.82
0.87
150
1,880
2,045
2,216
0.65
0.69
0.74
160
1,547
1,688
1,836
0.55
0.59
0.63
170
1,280
1,402
1,531
0.46
0.50
0.53
180
1,065
1,170
1,282
0.39
0.42
0.45
190
890
982
1,078
0.33
0.36
0.39
200
748
828
913
0.28
0.31
0.33
210
631
701
766
0.24
0.26
0.28
212
611
678
751
0.23
0.25
0.28
*Circuit volts = 5 vdc.
Table 11 — Troubleshooting
PROBLEM
POTENTIAL SOURCE
ACTION
Unit does not operate
Circuit breaker has tripped or fuse is blown
Reset the circuit breaker or replace the fuse.
Power failure
Restart fan coil unit operation when power is
restored.
Voltage is too low
Confirm the available voltage.
Insufficient Cooling
Air filter is blocked with dust
Clean the air filter.
Temperature is not set properly
Check and reset if necessary.
Window(s) and/or door(s) are open
Close window(s) and door(s).
Outdoor unit is obstructed
Remove the obstruction.
Fan speed is too low
Change the fan speed
Operation mode is set to fan or auto. mode
Change to cooling operation or reset temperature
(using remote controller).
Insufficient Heating*
Air filter is blocked with dust
Clean the air filter.
Temperature is not set properly
Check and reset if necessary.
Window(s) and/or door(s) are open
Close window(s) and door(s).
Outdoor unit is obstructed
Remove the obstruction.
Unit stops during operation
Off timer is operating
Turn off the off timer function.
Room temperature has reached the programmed
set point
Normal unit operation.
*Heat pump systems only.
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