Friedrich H)A09K25 Manual De Usuario

39

9-18 ELECTRICAL TROUBLESHOOTING CHART — COOLING

Line Voltage 

available at fan 

speed switch

(on models so 

equipped)

NO COOLING

Insure that Fuses 

are good and/or that 

Circuit Breakers are 

On

Compressor and Fan 

Motor should now 

operate

See Refrigerant Circuit 

diagnosis if unit still is 

not cooling properly

Fan runs but 

Compressor doesn't

Compressor runs but 

Fan doesn't

Turn Fan Switch of Room 

Thermostat to "On" 

position or jump "R" to 

"G" at Terminal board

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

24 Volts at 

Transformer 

Secondary?

24 Volts present at 

Cool Relay?

Check Supply Circuit 

for loose connections 

or broken wiring

Problems indicated with 

Control Transformer

Check Supply Circuit 

for loose connections or 

broken wiring

Problems indicated with 

Room Thermostat or 

Control Wiring

Does Fan Motor operate 

now?

Problem indicated in 

Control wiring and/or 

Room Thermostat

24Volts at Coil 

Terminals of Blower 

Relay?

Problem indicated in 

Control Wiring and/

or Room Thermostat

Problems indicated 

in Blower Relay

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

O.K.

O.K.

O.K.

No

Is Line Voltage present 

at Motor Leads?

Check Fan

Speed Switch

(on models so equipped)

or Blower Relay on later 

models

Check Capacitor, is 

Capacitor Good?

Replace Capacitor

Motor should run

Possible motor 

problem indicated.  

Check motor 

thoroughly

Yes

Yes

No

No

No

Fan Motor operates, 

but Compressor 

doesn't

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

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

Yes

No

No

No

No

Yes

Compressor and fan 

motor should now 

operate

See Refrigerant 

Circuit Diagnosis if 

unit still is not cooling 

properly

Yes

No

Yes