Running but not cooling: two Live Oak houses, the same complaint, two different bills

The two calls

House one: a 1976 block ranch in Sherwood Forest. The thermostat is set at 75 and reads 82. The air from the ceiling registers is moving at normal speed but is barely cooler than the room. Outside, the condenser is humming, the fan on top is not turning, and the cabinet is hot to the touch.

House two: a manufactured home near Wellborn, on SVEC power. Same thermostat gap. The outdoor package unit is running normally and the air at the registers nearest it is cold. The back bedrooms get almost nothing, and the floor under the hallway is sweating.

Both homeowners say the same sentence on the phone: it’s running but it’s not cooling. The fixes could hardly be more different.

The same complaint, side by side

	Block ranch	Manufactured home
Air volume at the vents	Normal	Weak, worse at the far end
Outdoor unit	Humming, fan stopped	Running normally
Likely cause	Failed condenser fan motor or its capacitor	Torn or collapsed belly duct under the floor
What ignoring it costs	A compressor, if the unit keeps running	Weeks of high bills and a damp crawlspace, then mold
Fix scale	A part, one visit	A crawl, duct repair, one visit

Every cause we see, ranked by what it costs to ignore

1. Outdoor fan stopped, compressor running. Capacitor or fan motor. Cheap part; expensive if the compressor cooks while you wait. Shut it off.
2. Refrigerant leak. The air gets gradually warmer over days or weeks. Running low on charge overheats the compressor and freezes the coil. Needs a leak search, not a top-off.
3. Contactor or control board failure after a storm. Common across Suwannee County after lightning or a generator week. The outdoor unit may not run at all while the indoor fan does.
4. Dirty or blocked outdoor coil. Pine straw, grass clippings, cottonwood fluff. The unit runs hot and cools poorly. A rinse fixes it; neglect shortens the compressor’s life.
5. Duct failure. Belly duct under a manufactured home, disconnected attic flex in a ranch. Air is cooled and then dumped under the house. Costs money every hour but does not damage the equipment.
6. Frozen indoor coil. From low airflow or low charge. Air goes weak, then warm. Has its own page.
7. Thermostat or wiring. Rare, cheap, and the first thing we rule out.

What to do before the truck arrives

• Check the filter. A filter that has not been changed since pollen season can starve the system enough to cause weak, warm air on its own.
• Look at the outdoor unit. Fan turning or not? Coil matted with debris? Note it.
• Feel the air at the register nearest the air handler and at the farthest one. A big difference means ducts; no difference means equipment.
• If the outdoor fan is stopped and the unit is humming, turn the system off.
• Do not add refrigerant from a hardware-store can, and do not hose down a running unit’s electrical side.

Call about warm air now

What the visit covers

We start outdoors on a warm-air call because that is where the fast, dangerous failures live: capacitor readings, fan and compressor amps, contactor, pressures. Then indoors: filter, coil, blower, drain and float switch. Then the ducts, with a walk of the attic or a crawl under the home. On manufactured homes near Wellborn, McAlpin and the river we expect to go under the floor and bring the gear for it. You get the diagnosis and the price before the repair, and if the system is an older R-22 unit with a coil leak, you get the replace-or-repair numbers on the same visit.

Keeping it from happening in August again

The ranch needs its capacitors checked each spring and its outdoor coil rinsed after the pollen and the cottonwood pass. The manufactured home needs its belly duct inspected every maintenance visit and after any flood or animal damage. Both need a float switch on the drain if they do not have one, because well-water scale closes a drain line faster here than almost anywhere we work.