AC Repair in Saddle Rock Ridge, Aurora

When a system in this part of southeast Aurora loses refrigerant two summers running, the leak is more often on the indoor coil than anywhere in the outdoor unit. That matters because an indoor leak is invisible, silent and does not leave an oil stain on a concrete pad where anyone would notice it. MoJo Home Services works this subdivision at 5,407 feet in Arapahoe County. Licensed, insured and EPA-certified: 720-807-4050.

Why does the indoor coil leak before anything else?

Evaporator coils are built from thin-walled copper tubing, and they sit in a moving stream of house air. Where that air carries organic acids, from cleaning products, adhesives, finishes and other everyday indoor sources, the copper can develop formicary corrosion: microscopic tunnels eaten through the tube wall from the outside in. The resulting pinholes are far too small to see and too slow to hear, and they release refrigerant over months. The system keeps working, a little worse each season, until capacity drops far enough that someone calls.

How is a leak that small actually found?

In stages. An electronic leak detector sweeps the coil and the accessible joints first. Suspect areas get confirmed with bubble solution, because detectors respond to things other than refrigerant. If nothing is confirmed and the loss rate is slow, the system gets isolated and pressurised with dry nitrogen for a standing pressure test, which turns an invisible leak into a measurable pressure drop over time. Ultraviolet dye is the slowest method and the last resort, because it requires the system to run for a period before anything shows.

Should a leaking coil be repaired or replaced?

Coil corrosion rarely comes as a single defect. A tube wall thin enough to have opened in one place is usually thin in others, so a spot repair on a formicary leak commonly buys a season rather than a decade. Replacement brings its own conditions: the new coil has to be a proper match for the outdoor unit and the metering device, the refrigerant generation has to line up, and the age and condition of the compressor decide whether the rest of the system deserves a new coil at all. Those are the facts that make the decision, and we lay them out rather than deciding for you.

Does 5,407 feet change how a leak behaves?

Not the leak itself, which is driven by system pressure rather than altitude. What changes is how quickly you feel it. At 5,407 feet the air is about 14.9% less dense than at sea level, so a system needs roughly 470 CFM per ton against the tabulated 400 just to deliver rated capacity, and there is no surplus sitting in reserve. A charge shortfall that a coastal house might not notice until August is obvious in June here. Gas-fired equipment separately derates 13.6% at this elevation.

Why does Saddle Rock Ridge share its elevation with Tallyn's Reach?

Because both sit at 5,407 feet on the same stretch of southeast Aurora ground. That means altitude tells the two communities apart on nothing at all: identical derate, identical density correction, identical airflow target. What actually differs between service calls in these two subdivisions is the equipment and what is failing on it, which is why this page is about coil leaks and the neighbouring one is about staged equipment.

What ends the cycle of adding refrigerant each year?

Finding the leak, then deciding on the coil with the numbers in hand. A system topped up annually is a system whose owner is paying repeatedly for the same fault while the compressor works against a low charge and returns less oil than it should. Refrigerant recovered and reweighed also tells us how much escaped and over what period, which is the single most useful number for deciding whether a repair holds or the coil has to come out.

What does running low on refrigerant do to the compressor?

It removes the cooling the compressor depends on. In most residential systems the returning suction vapour passes over the motor windings and carries their heat away, so a low charge means less mass flow and a hotter motor. Oil return suffers at the same time, because the oil circulating with the refrigerant needs velocity to make it back to the compressor. Add rising superheat and longer run times and a system limping along on a slow indoor leak is wearing out faster than one that gets the leak fixed. That is the practical argument for finding it rather than feeding it.

Southeast Aurora on the same route

We cover Tallyn's Reach at the same elevation, Murphy Creek to the north, and the rest of Aurora heading back toward the metro.

Same crews, neighbouring towns

Neighbouring work: AC repair in Aurora, AC repair in Murphy Creek, AC repair in Tallyn's Reach, AC repair in Pheasant Run, AC repair in Reunion, AC repair in Watkins.

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

More on the service itself: AC repair.