SystemAir changeair Freshman Series - Cooling Troubleshooting

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Freshman Series - Owner's Manual - Installation, Operation, and Service Instruction - Version 1.1 EN
Changeair is not responsible for injury to untrained or unauthorized personnel who
attempt to do repairs based on the trouble shooting procedures outlined in this section.
NOTE:
Mechanical cooling
should not operate
when outside
temperature is below
60°F (17°C), as the
economizer (“free
cooling”) will be in
operation.
8.7 Cooling Troubleshooting
Problem - Temperature drop between mixed air and supply is less than 18°F. If it
is more than this, the unit is operating properly.
1. Check for dirty condenser, evaporator coil or lter, clean as necessary
2. Test for over or under charged unit; adjust accordingly.
3. Conrm fan is running at full speed, and check amperage draw.
4. Check for unit running low suction psi, possible dirty evaporator or lter, clean
as needed.
Problem - Related to iced over evaporator coil
1. Conrm fan and compressors are running at full speed.
2. Check for dirty air lter.
3. Check for dirty evaporator coil.
4. Possible restrictions in the line, TXV capillary tube or evaporator.
5. Check thermostat set point. (If room temperature drops below 70°F (21°C), the
evaporator may ice over during extended operation.
6. Check for low refrigerant charge.
Problem - Compressor Cycles Off and On
1. Low voltage; check for proper supply voltage at unit.
2. Restriction in the air across the condenser; check and clean as required.
3. Check high-pressure switch and/or low pressure switch (if equipped).
4. Conrm the condenser fan and supply fan operation. Possible fuse open, relay
defective, or fan motor faulty.
Problem - Compressor Not Running
1. Ensure control circuit is producing a cool signal.
2. Check fuses or breaker. Check for “supply VAC” at relay, then at compressor.
3. Test for 24VAC across relay, check safeguards, freeze protection, high pressure
cut out.
4. Test run capacitor (if equipped)
5. Check unit is not in economizer mode below 60°F (17°C) outside ambient.
Troubleshooting Guide