9-18 Electrical Troubleshooting Chart - Cooling - Friedrich H)A09K25 Service Manual

9-18 ELECTRICAL TROUBLESHOOTING CHART — COOLING
Compressor runs but
Fan doesn't
Yes
Turn Fan Switch of Room
Thermostat to "On"
position or jump "R" to
"G" at Terminal board
O.K.
Does Fan Motor operate
now?
Yes
Problem indicated in
Control wiring and/or
Room Thermostat
Is Line Voltage present
at Motor Leads?
No
Yes
Check Capacitor, is
Capacitor Good?
No
Yes
Motor should run
No
Fan runs but
Compressor doesn't
No
Yes
No
24Volts at Coil
Terminals of Blower
No
Relay?
Yes
Line Voltage
available at fan
speed switch
(on models so
equipped)
Yes
Check Fan
Speed Switch
(on models so equipped)
or Blower Relay on later
models
Replace Capacitor
Possible motor
problem indicated.
Check motor
thoroughly
NO COOLING
Insure that Fuses
are good and/or that
Circuit Breakers are
On
O.K.
Set thermostat to
"Cool," move the Temp.
lever below the present
Room Temp.
O.K.
Compressor and Fan
Motor should now
operate
Yes
See Refrigerant Circuit
diagnosis if unit still is
not cooling properly
Problem indicated in
Control Wiring and/
or Room Thermostat
Problems indicated
in Blower Relay
No
Supply Circuit
problems, loose
Connections, or bad
Relays
Replace Capacitor
and/or Start Assist
Device
Allow ample time
for pressures to
equalize
Possible Compressor
problem indicated.
See Compressor
Checks
Nothing operates,
entire system
appears dead
Yes
No
Line voltage present
at the Transformer
Primary
No
Yes
24 Volts at
Transformer
Secondary?
No
Yes
24 Volts present at
Cool Relay?
No
Yes
Fan Motor operates,
but Compressor
doesn't
Yes
Is Locked Rotor
Voltage a minimum of
197 Volts?
No
Yes
Are Capacitor and (if
so equipped) Start
Assist good?
No
Yes
Have System
Pressures Equalized?
No
Yes
Compressor should
run
No
Check Supply Circuit
for loose connections
or broken wiring
Problems indicated with
Control Transformer
Check Supply Circuit
for loose connections or
broken wiring
No
Problems indicated with
Room Thermostat or
Control Wiring
Compressor and fan
motor should now
No
operate
Yes
See Refrigerant
Circuit Diagnosis if
unit still is not cooling
properly
39