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Yes
No
24V at t-stat and
control wiring?
Yes
No
24V at t-stat and
control wiring?
NO COOLING OPERATION
Before continuing
check for Error
Codes, see
electronics control
diagnostics and
test mode, page 15
Yes
Yes
Compressor outdoor
fan motor and indoor
blower should now
operate
See Refrigerant Circuit
diagnosis if unit still is
not cooling properly
Indoor blower runs but
outdoor fan motor and
compressor do not run
Compressor and outdoor
fan motor run but indoor
blower does not run
Set thermostat to
"Cool," move the Temp.
lever below the present
Room Temp.
Nothing operates,
entire system
appears dead
Line voltage present
at the Transformer
Primary
Problems indicated with
Room Thermostat or
Control Wiring
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
O.K.
No
Is Line Voltage present
at Motor Leads?
Check Capacitor, is
Capacitor Good?
Replace Capacitor
Motor should run
Possible motor
problem indicated.
Check motor
thoroughly
Yes
Yes
Yes
No
No
No
Supply Circuit
problems, loose
Connections, or bad
Relays/Board
Replace Capacitor
and/or Start Assist
Device
Allow ample time
for pressures to
equalize
Possible Compressor
problem indicated.
See Compressor
Checks
Is Locked Rotor
Voltage a minimum of
197 Volts?
Are Capacitor and (if
so equipped) Start
Assist good?
Have System
Pressures Equalized?
Compressor should
run
Yes
Yes
No
No
No
No
Yes
Compressor and
outdoor fan motor
should now operate
See Refrigerant
Circuit Diagnosis
if unit still is not
cooling properly
Yes
Insure that Fuses
are good and/or that
Circuit Breakers are
on and voltage is 208/230
O.K.
208/230 Volts present
at #1 relay and “OD”
terminal on board?
208/230 Volts present
at compressor’s
contactor?
Problems indicated
in Blower Relay
of board
Replace board
Check Supply Circuit’s
jumper at transformer. If
okay, replace board
24 Volts at
“R” Terminal on board
24 Volts present at
Y terminals on
t-stat and board?
Problems indicated with
Control Transformer
replace board
Defective t-stat
defective control wiring
or transformer
Check contactor
If defective replace
41