Keystone Insufficient Cooling / Low Capacity Operation

Keystone air conditioner runs but does not cool the room effectively; air from the front is only slightly cool or room temperature.

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Dirty air filter, clogged evaporator or condenser coil, low refrigerant charge, failing compressor, incorrect BTU size for room

How to Fix / Troubleshooting

Safety: Unplug the unit before cleaning internal components.

Steps:

  • Verify mode and settings: Ensure the unit is in COOL mode, fan speed is not on low only, and the set temperature is at least 5°F (3°C) below room temperature.
  • Clean filter and coils: Wash the filter and gently clean both evaporator (indoor) and condenser (outdoor) coils to restore heat transfer.
  • Check installation: For window units, ensure gaps around the chassis are sealed so hot outdoor air is not leaking inside. For portables, ensure the exhaust hose is properly vented outdoors.
  • Assess room size: Compare the unit's BTU rating to the room size. An undersized Keystone unit will run continuously and still struggle to cool.
  • If still weak: If airflow is good and coils are clean but cooling is poor, the sealed system may be low on refrigerant or the compressor may be weak. Contact a certified technician for pressure testing and possible sealed system repair.
Advertisements

Repair Difficulty

Medium 3/5

Required Part

Compressor or Sealed System (if not an airflow/size issue)
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements