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Section E - Symptom/Cause Chart
80
DUO-THERM ROOF MOUNTED HEAT PUMPS
This program will address the most common system problems associated with the Duo-Therm Heat Pumps supplied by The
Dometic Corporation. Our intent is to provide you with a guideline of checks to make, should you encounter one of the
following symptoms.
SYMPTOMS
CAUSE
REFER TO
PAGE
1.Unit does not run; no fan, no compressor
(Cool or Heat mode)
Mechanical Controls
Operation
B2a
24
Ambient Temperature
C22a
59
AC Voltage
A1
1
Breaker
A4
2
Changeover Thermostat
C10
32
Selector Switch
C9
31
Wiring
A3, C21
1, 58
Bimetal Control System
Operation
B2b
24
Ambient Temperature
C22a
59
AC Voltage
A1
1
DC Voltage
A2
1
Breaker
A4
2
Changeover Thermostat
C10
32
Wiring
A3, C21
1, 58
Bimetal Thermostat
C18b
42
Relay
C16
35
Relay Board
C17a
38
Cable Assembly
C19
52
Analog Control System
Operation
B1c
15
Ambient Temperature
C22a
59
AC Volts
A1
1
DC Volts
A2
1
Fuse
C15
34
Breaker
A4
2
Changeover Thermostat
C10
32
Analog Thermostat
C18c
50
Analog Control Box
C17b
39
Wiring
A3, C21
1, 58
Comfort Control Center
Configuration
D
60
Operation
B2d
26
Ambient Temperature
C22a
59
AC Voltage
A1
1
DC Voltage
A2
1
Breaker
A4
2
Fuse
C15
34
Cable Assembly
C19
52
Ambient Sensor
C12
33
Comfort Control Center
C18d
52
AC Power Module Board
C17d
40
Manual
Compliments
of
Northwest
RV
Supply
Printed
From
http://www.nwrvsupply.com