Heat pumps fail differently than standard AC or furnace systems, and diagnosing them requires understanding the reversing valve and defrost board specifically.
A heat pump stuck in one mode, or one that's iced over and won't defrost, gets diagnosed with the right tools for that specific failure mode.
If you're dealing with a system stuck blowing cold air in heating mode, an outdoor unit that's iced over and won't run its defrost cycle, or a system that switches modes but never actually reaches set temperature, you already know a heat pump that seems to be 'not heating' is often actually a reversing valve or defrost cycle problem, which a technician trained mainly on standard AC systems can easily misdiagnose.

Most heat pump repair problems give some warning before they turn into a system stuck blowing cold air in heating mode, an outdoor unit that's iced over and won't run its defrost cycle, or a system that switches modes but never actually reaches set temperature — catching it early usually means a shorter, cheaper fix.
AAA Pro HVAC built its heat pump repair process around one idea: diagnose first, quote honestly, fix it right.
We're licensed, insured, and staffed with techs who've spent years specifically on heat pump repair, not general handyman work with an HVAC certificate bolted on.

Heat pump failure modes are different enough from standard AC that generic diagnostics often miss the actual cause.
No-heat calls in winter get the same priority as no-cool calls in summer.
You get a quoted price after the reversing valve and defrost cycle are actually tested, not billed for trial-and-error.
We test reversing valve solenoids, defrost thermostats, and control board timing directly.
Every job starts with a real diagnosis, not a guess — here's the full scope of what our heat pump repair technicians handle across Sterling, VA.
A stuck reversing valve is the single most common reason a heat pump gets stuck in one mode. This is one of the most requested heat pump repair calls we get across Sterling, VA.
We verify the defrost cycle actually triggers under test conditions. Techs handling defrost cycle & control board repair carry the specific parts and tools this job calls for, not a generic kit.
We test heat strip elements and the relay controlling them separately. Techs handling auxiliary / emergency heat strip repair carry the specific parts and tools this job calls for, not a generic kit.
Heat pump refrigerant charging follows different specs than standard AC systems, especially across heating and cooling modes. This is one of the most requested heat pump repair calls we get across Sterling, VA.
Some icing is normal during defrost cycling; persistent icing that never clears points to a genuine fault. Techs handling outdoor unit icing diagnostics carry the specific parts and tools this job calls for, not a generic kit.
Indoor head unit and outdoor condenser are diagnosed as a connected system. This is one of the most requested heat pump repair calls we get across Sterling, VA.

Describe whether the system is stuck in one mode, iced over, or not heating/cooling at all.
Heat pump-trained technicians arrive with reversing valve and defrost diagnostic equipment already loaded.
Reversing valve, defrost cycle, and refrigerant charge are tested against heat pump-specific specs before any quote.
Most reversing valve and defrost board repairs finish same-visit with parts carried on the truck.

Previous company just topped off refrigerant twice — this tech found the stuck reversing valve in ten minutes.
Turned out the defrost thermostat had failed, so it never actually triggered the defrost cycle.
They tested the relay separately from the strips themselves and found the actual fault fast.
Ductless heat pump in the addition threw a code I couldn't find anywhere online.

Often a stuck reversing valve, which controls whether the system is in heating or cooling mode.
If the unit stays iced for more than an hour, that's worth a service call.
A technician needs specific training on these components to diagnose heat pump issues accurately.
If auxiliary heat isn't kicking in properly, that's a specific fault we can test for.
Yes — indoor head units and outdoor condensers on ductless heat pump systems are within our service scope.
No-heat heat pump calls get year-round priority dispatch across Sterling, VA.

Whether you're in the heart of Sterling or one of the surrounding communities, dispatch routes the closest available technician.
☎ Call +1-866-805-8548 for Sterling Service