Heat pump repair in Lorton.

Lorton is young. The median owner home went up in 1997, and more than four in ten owner homes were built after 2000. That makes most heat pumps here the original or the first replacement, ten to twenty years old. At that age, the old reliable failures like a tired capacitor still turn up, but so do the electronic ones: the defrost board, the outdoor temperature sensor, the thermostat that stops talking to the system.

Those faults have a signature. A pump with a failing sensor or board often does odd things rather than nothing: it runs but never defrosts, it cycles on and off every few minutes, it shows an error code on the thermostat or on the air handler’s light. Write down the code or the number of blinks before you call. It narrows the list fast, and we can often bring the right board.

About a third of the homes in 22079 are townhouses, and in the townhouse communities the outdoor units sit on small pads along the back of the row. Space is tight, the units are close together, and a unit that icing up on one side of the row but not the other is telling you something about its own airflow or defrost, not the weather. Air handlers are in closets or attic spaces, so keep the filter changed and the closet door clear.

On Mason Neck, the houses are single-family and older, and the pumps were more often added or replaced over time. Newington on the north edge is more like the townhouse side of Springfield. For a repair, the difference matters less than the age and the make of the unit. Have the model plate photographed or the numbers read to us, and we will know what we need to carry.