Operating instructions

57
RELAY
10 A MP
RELAY
10 A MP
RELAY
10 A MP
LOW
MED
HIGH
TB6
TB5
TB4
COOL CONT ROL
TB2 TB1
NO
HEAT
RELAY
30 A MP
NO COM
TO A .C. W HITE
ARROW DESIGNAT ES
PIN #1
RIBBON
CABLE
DC VOLT CONTROLLEDDC VOLT CONTROLLED
DC VOLT CONTROLLEDDC VOLT CONTROLLED
DC VOLT CONTROLLED
E.E.
E.E.
E.
RELAY BOARDRELAY BOARD
RELAY BOARDRELAY BOARD
RELAY BOARD
The relay board is controlled by the bimetal type thermo-
stat. It consists of a transformer, compressor relay, two fan
relays and other components. If any one of these are
defective the complete relay board must be replaced.
The relay board completes circuits to the fan motor and
compressor depending on what mode switch and tempera-
ture setting is on the thermostat.
The first check would be to turn all power OFF to the air
conditioner. Disconnect the four wires (red, yellow, orange
and blue) from the thermostat wires and wire all four wires
together. Turn power ON to the air conditioner. The com-
pressor and high fan should operate. Next, remove the blue
wire from the others. With the red, yellow and orange wires
connected, the compressor and low fan should operate. If
these checks are not correct, the problem is in the relay
board or its wiring.
Remove the cover from the relay box housing and verify the
red wire is on terminal RC, orange wire is on terminal G,
blue wire is on terminal H and yellow wire is on terminal Y.
With AC power to the relay board, check between terminals
RC and G or H. There should be 12 volts DC. If no voltage
is detected, the transformer on the relay board is defective.
Replace the relay board.
If 12 volts DC is available, disconnect power to the air
conditioner and remove the HI FAN wire (black) and the
LOW FAN wire (red) and the compressor wire (large blue)
from the NO terminal on the compressor relay on the relay
board.
TB 9
Y
TB 8 TB7
FREEZE
TB 4
RC
TB 5
G
TB 6
H
RELAY
10 A MP
RELAY
10 A MP
TB1
AC W HT
TB3
FAN HI
TB2
FAN L OW
COM
NO
DOMETIC CORP ORATION
ASM. #3104757.004
115V AC
INCANDESCENT
BULB
D.C.
VOLT
Next, connect together all four low voltage wires (red,
yellow, orange and blue) that go to the thermostat from the
relay box. Provide power to the air conditioner. Using an
incandescent bulb, check from AC WHITE terminal (one
lead from bulb) to NO terminal and HI FAN terminal (other
lead from bulb). The bulb should illuminate. Next, discon-
nect the blue wire from the other three. Check from AC
WHITE to LO FAN and NO terminals. The light should
illuminate. If these tests are correct, the relay board is good.
Do NOT replace it. If any one of these tests are incorrect,
replace the relay board.
RELAY BOARDRELAY BOARD
RELAY BOARDRELAY BOARD
RELAY BOARD