Air Conditioning Repair in Boulder, CO

Boulder sits at 5,328 feet, the lowest ground of the eight communities in this group, which makes the altitude arithmetic here the mildest we deal with: a 13.3% gas derate against 14.3% at the top of the cluster, one percentage point across the whole set. So elevation is not what makes a Boulder cooling repair different. Equipment type is. If the outdoor unit at your Boulder County home is a heat pump rather than a straight air conditioner, the cooling-season diagnosis changes in several places. MoJo Home Services, 720-807-4050.

Is the outdoor unit at my Boulder home an air conditioner or a heat pump?

Three ways to tell without tools. Look inside the outdoor cabinet for a reversing valve, a brass cylinder roughly the size of a soda can with three tubes entering below and one above; a cooling-only condenser does not have one. Check whether the thermostat offers an emergency heat or auxiliary heat setting, which only a heat pump needs. And read the model number on the rating plate, where heat pump models are usually marked. It matters in July, because a heat pump can fail in ways a cooling-only condenser physically cannot.

What fails on a Boulder heat pump during cooling season?

The reversing valve solenoid comes first. When it fails to energize, or the valve sticks part-way through its stroke, refrigerant bypasses internally and the system delivers lukewarm air with suction and discharge pressures sitting oddly close together. Second is the defrost board, which can hold the unit in a mode it does not belong in during summer. Third is the bi-flow metering device or its check valve, which has to work in both directions and can pass freely one way while restricting the other. None of those are refrigerant faults, and all three get misdiagnosed as one.

Does Boulder's 5,328 feet actually change the cooling numbers?

Less than altitude talk usually implies, and we would rather say so plainly. Boulder air is about 14.7% less dense than sea-level air, which puts the airflow target near 469 actual CFM per ton instead of the 400 printed in sea-level tables. That is a real correction and we apply it. It is also within a few CFM per ton of what we apply on the highest ground we cover. What genuinely varies from one Boulder job to the next is the gap between what the blower should deliver and what it does deliver, and that is a duct, filter, and coil question rather than a map question.

What does a Boulder County cooling diagnostic include?

For a heat pump: reversing valve position under a cooling call, solenoid coil resistance, defrost board sequence, outdoor sensor accuracy, and both metering paths. For a straight air conditioner: capacitance against the stamp, contactor condition, compressor and fan amp draws, superheat, and subcooling. For either machine: static pressure across the air handler, delivered airflow, and the temperature split, which in Boulder's dry summer air lands nearer 20 to 25°F than the 16 to 20°F humid-climate references list. Boulder's 106,803 residents own a real mix of furnace-and-AC pairings, heat pumps, and dual-fuel systems, so we identify the machine before diagnosing it.

What about a dual-fuel system?

Dual fuel means a heat pump outdoors and a gas furnace indoors, switched by outdoor temperature at a balance point. In cooling season the furnace is idle and the heat pump behaves like an air conditioner, so the summer diagnosis is the heat pump's. The furnace still matters, because it holds the blower and because Boulder's 13.3% derate at 5,328 feet pushed it up a size, and an oversized cabinet chosen for winter is what your evaporator coil breathes through in July. A cooling complaint on a dual-fuel system is one diagnosis across two machines.

Boulder County neighbors we cover

Lafayette and Erie sit east of Boulder on the same routes, and Broomfield anchors the southeast corner where Boulder County traffic meets the metro. Each has its own elevation, and none of them get Boulder's 5,328-foot figure applied on their behalf.

Same crews, neighbouring towns

The same trucks run AC repair in Lafayette, AC repair in Broomfield, AC repair in Erie on the same rotation.

Heating and cooling fail for different reasons in the same house — see furnace repair in Boulder.

More: AC repair · everything in Boulder.