A heat pump functions as both a central heating and a cooling appliance that delivers air through a duct system. Similar to a forced-air furnace, the heat pump requires a little more maintenance than a furnace, although troubleshooting may lead you to some of the same results that you would get troubleshooting a forced-air furnace heating and cooling system.
Inspect the thermostat to see that it has not been adjusted too high or low for the unit to kick on when you begin to get uncomfortable. If the thermostat appears to be working appropriately, check the main service panel for a blown fuse or tripped circuit breaker, depending on your system.
Set the thermostat on your heat pump to "Automatic Heat" if you notice that ice has built up on the coils. Ice can cause the fins on the outdoor unit to become bent, so inspect the fins after the ice has melted. Use a tool called a fin comb to straighten the fins on the outside condenser unit.
Check that the heat pump is situated perfectly level if you begin to notice a reduction in the efficiency of the system. You should check the level of the outdoor unit once a year and then again after a particularly damp spell. Use a carpenter's level to gauge whether the unit is level both horizontally and vertically.
Unscrew and remove the top panel and the side screens of the heat pump to perform troubleshooting duties. Inspect the fan system to make sure that the fan blades are not bent or obstructed.
Vacuum the fins on the outdoor unit and then inspect the fins for any that are bent. Use the fin comb to straighten out the fins, making sure to wear gloves to protect yourself against the sharp edges of the fins.
Locate the oil fan motor and clean the fan blades after you have straightened any bent fins. Use a brush to clean the fan blades. Lubricate the fan motor with SAE-30 nondetergent lubricating oil.
Clean away any debris, including snow, from the outdoor heat pump unit. You want to ensure clear and clean air flow. This extends to checking the indoor air filter on a monthly basis and even more frequently during dusty seasons or periods of heavy use. Replace a dirty air filter before it can start having a noticeably adverse effect on performance.
Set the thermostat to "Cool" and wait for a half hour before you reset the thermostat to "Heat" if the Emergency Heat light seems to be permanently stuck in the on position. This is most likely caused by a stuck reversing valve. If the air is still not getting cool call for repair.
Use a germicidal cleaner on the evaporator coils if you notice an air conditioner smell when you first turn it on. Cleaning the coils will help make the air cleaner as it is initially expelled through the duct system.