HVAC Troubleshooting

Two central condensers and a larger outdoor unit are installed beside a new home — HVAC troubleshooting

Real diagnostic guides for the HVAC problems we get called about most. Written by a family that’s been fixing these systems since 1996 – not marketing copy, not scary sales pitches. If you can fix it yourself, we tell you. If you can’t, we’ll help.

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Watch: 60-second intro

Sheddie explains how to use this troubleshooting library. (Video coming soon — swap this block for the real embed once shot.)

Cooling
My AC is blowing warm airThe thermostat says 68 but the vents feel like a heater. Four common causes.
My AC won't turn on at allNothing happens when the thermostat calls for cool. Where to look first.
My AC keeps freezing upIce on the copper line outside. Water dripping inside. The two real causes.
There's water leaking from my ACPuddle under the air handler or water stain on the ceiling. Almost always the drain.
One floor is cold and the other is hotUpstairs is a sauna. Downstairs is a meat locker. Usually not a new system.
One room won't coolThe back bedroom, the bonus room, the office. Three checks before a mini-split.
Heating
My furnace won't igniteBlower runs but no flame. Ignitor, flame sensor, or gas supply.
My furnace keeps shutting off too soonOn for two minutes, off for two, over and over. Wearing itself out.
My furnace is blowing cold airThermostat set to heat but only cold air comes out. Three real causes.
My pilot light won't stay litOlder furnace with a standing pilot. It lights then dies. Almost always the thermocouple.
Heat Pumps
My heat pump runs all the timeEspecially in winter. Sometimes normal, sometimes not. How to tell.
My heat pump is frozen over outsideIce on the outdoor coil in winter. Normal – up to a point. How to tell.
Air Quality
The AC runs but the house feels stickyCool but sticky. Common in humid Tennessee summers. Not always the AC's fault.
There's a musty smell coming from my ventsWet-basement smell when the AC kicks on. Coil, drain pan, or ductwork.
Operational
My HVAC unit is making loud noisesBang, squeal, grind, or hiss. Each sound points to a different problem.
My utility bill is way higher than normalBill doubled and nothing else changed. Where HVAC is usually to blame.
The air from my return grille is weakBarely any air at the return. Filter, ductwork, or blower.
My ductwork is whistling or howlingWhistling from vents or ductwork. Static pressure or air leaks at joints.
There's water pooling near my furnacePuddle around the base of the furnace. AC condensate or high-efficiency furnace drain.
Foam Houses
My foam-insulated house's HVAC short-cyclesFoam-insulated homes need different sizing. Most HVAC guys refuse them. We don't.
My foam-insulated house has hot and cold roomsFoam houses concentrate temperature differences. Single zone almost never works.
My foam house is cold but humidFoam house is cool but sticky. The AC is oversized and never runs long enough to dry the air.
How to right-size HVAC for a foam-insulated houseGetting new HVAC in a foam house? Insist on a Manual J. Most contractors won't do one.
My last HVAC contractor gave up on my foam houseYour last HVAC guy won't come back or keeps swapping parts that don't fix it. Foam-house-specific problem.

Don’t see your problem?

Call us. If it’s HVAC and it’s in the Sequatchie Valley, Chattanooga metro, North Georgia, or Sand Mountain Alabama, we’ve seen it.

Call (423) 637-1846
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