Table of Contents
Advertisement
Table 5_Troubleshooting
Chart
SYMPTOMS
Air too humid
Unit not responding
to wall control
CAUSES
Continuous
exchange mode
used in small houses
Defrost condition is in effect
Outdoor temperatue
is below 23°F
Broken control wire
Unit stops momentarily
Electncal supply interrupted
Air from distribution
register too cold
Improper calibration of air flow
Unit makes annoying
noise
Ventilation wheel out of adjustment
Noise level too high at distribution
Air duCt system too short
registers
when in high speed
SOLUTIONS
Use Intermittent Mode
Check humidity level settings
Unit will operate when not in defrost mode.
Defrost cycle is based on outdoor ambient (see
Table 10)
Test wall control
Check connectior_s
Check thermistor
Check units circuit breaker
Check calibration of flow rates
Remove the motor and screw wheel on propedy
install a duct silencer
Table 6_Temperature/Ohrn
Relationship
TEMPF °
OHMS
30
34,480
32
32,630
34
30,760
36
29,220
38
27,470
40
26,020
42
24,680
44
23,320
46
22,070
48
20,910
50
19,830
52
18,820
54
17,870
56
16,920
58
16,160
60
15,260
62
14,530
64
13,790
66
13,090
68
12,480
70
11,860
72
11,270
74
10.750
76
10,250
78
9,750
80
9,300
62
8,840
84
8,432
86
8,042
88
7,668
90
7,310
92
6,993
94
6,661
96
6,368
98
6,085
100
5,811
102
5,571
, 104
5,313
106
5,088
108
4,869
110
4,660
112
4,450
114
4,268
116
4,019
118
3,918
120
3,750
Table 7--Factory
Set Blower Connection
HIGH or
LOW Speed
CONTROL
MODULE
J1-6
No Connection
J1-4
MAIN ELECTRICAL
BLOWER
HARNESS CABLE
WIRE
Orange
Orange
NO Connection
Blue + Cap
Red
Red
SPEED
High
Me_um
Low
Table 8--Modify
Blower Connection HIGH
or MEDIUM Speed
CONTROL
MODULE
Jl_
J1-4
No Connection
MAIN ELECTRICAL
BLOWER
HARNESS CABLE
WIRE
Orange
Orange
Red
Blue
NO Connection
Red + Cap
SPEED
High
Medium
Low
Table 9_Temperature
and Voltage
TEMPERATURE
°F (oc)
-22 (-30)
-4 (-20)
8 (-16)
14 (-10)
32 (O)
41 (5)
50 (10)
68 (20)
VOLTAGE
DC
VOLTS (J4)
3.5
2.7
2.3
2.0
1.4
1.1
0.9
0.6
If defrost is not working properly, check for proper damper
operation. To do this, turn unit to OFF position. Damper should
close.
Safety Feature
This new control has an added safety feature. If microprocessor
does not detect the thermistor or detects a short circuit, unit will
automatically go into a 6 minute defrost cycle every 20 minutes.
DEFROST CHECK
1. Make sure defrost cable is properly connected into J4.
2. Make sure thermistor assembly is correct. Measure thermistor
temperature
reading with muhimeter. Select multimeter DC
measurement scale 0-20v. At connector J4 (without removing
thermistor cable), measure voltage between pins of thermistor
cable. Depending on temperature of outside air intake, values
should correspond with those in Table 9.
If reading is not correct (reading llv for short circuit or 5v for
open circuit), change thermistor assembly.
3. If thermistor is good, do a RESET and ,see if defrost works. If
defrost still does not work, change circuit board.
15
Hide quick links:
Advertisement
Table of Contents
