Common AC Problems & What to Do
Before you call — and while you wait — here are the most common air conditioning problems, what’s usually causing them, a few safe things you can try yourself, and how we fix each one. When in doubt, book a repair and we’ll take it from there.
A few of these you can safely check yourself and possibly fix in a couple minutes. A couple are worth doing just to keep your home comfortable while you wait for us. What to leave alone: refrigerant and any electrical inside the units — adding refrigerant is regulated and a sign of a leak that needs a real repair, and the capacitors inside an AC can hold a dangerous charge even with the power off. When it’s those, just book an AC repair.
What’s wrong — and what you can do
AC is blowing warm air / not cooling
What you can try: make sure the thermostat is set to Cool and the temperature is below the room temp; check that the outdoor unit is running; and replace a dirty air filter (a clogged filter is a surprisingly common cause). Then give it 15–20 minutes.
How we handle it: warm air usually means low refrigerant (a leak), a failed capacitor or compressor, a frozen coil, or a stalled condenser fan. We diagnose the real cause and fix it — see AC repair.
The AC is frozen / iced over
What you can do (this one matters): turn the thermostat to OFF for cooling but set the fan to ON — running the blower with cooling off helps the ice melt faster. Let it fully thaw before we come out (it can take a few hours); running a frozen system can damage the compressor. While it melts, keep an eye on the furnace/air handler and the drain pan and make sure the melting water isn’t leaking onto the floor or through the ceiling — lay down towels and empty the pan if needed. Also swap a dirty filter, since restricted airflow is a top cause of freezing.
How we handle it: we find why it froze — airflow restriction (filter/coil/blower) or low refrigerant from a leak — and fix the root cause so it doesn’t ice up again.
It’s hot and the outdoor unit (condenser) isn’t running
What you can do to stay comfortable: set your thermostat fan to ON (fan only). Even with the cooling/condenser down, running the furnace blower keeps air circulating through the house, which helps even out temperatures and keep it from feeling stuffy while you wait for us. (It won’t cool, but moving air helps.) You can also check that the outdoor disconnect and breaker haven’t tripped.
How we handle it: a condenser that won’t start is usually a failed capacitor or contactor, a bad fan motor, or a control issue — a common, straightforward repair once we’re on site.
Water leaking around the furnace / air handler
What you can do: turn the system off to stop more water, and mop up what’s there. The most common cause is a clogged condensate drain — and if your system has a float safety switch (we install these on every install), it may have shut the AC off on purpose to prevent an overflow.
How we handle it: we clear and flush the drain line, check the pan and float switch, and make sure it drains properly so it won’t shut down or cause water damage.
AC won’t turn on at all
What you can try: check the thermostat (fresh batteries, set to Cool), confirm the breaker for the AC and furnace/air handler hasn’t tripped, and make sure the furnace door/panel is fully closed (a safety switch cuts power if it’s off). Some systems also have a condensate float switch that disables cooling when the drain is clogged.
How we handle it: we confirm power and controls first — thermostat, wiring, transformer, board, safety switches — before recommending any part.
Weak airflow or some rooms won’t cool
What you can try: replace the filter, make sure supply and return vents are open and unblocked by furniture, and confirm the thermostat fan is on Auto (or On for more circulation).
How we handle it: weak airflow is usually a dirty blower or coil or a duct problem, not the AC itself. We measure static pressure to find the restriction — more on our airflow work.
Strange noises or smells
What you can do: if you smell something burning or electrical, turn the system off and call us. A musty smell is often a dirty coil or drain; a rattle can be a loose panel.
How we handle it: we trace the noise or smell to its source rather than guessing — and during the repair we use an inspection camera to check inside for buildup that hurts efficiency and air quality.
Want to understand your system better? Read our HVAC systems guide.
Common AC repair questions
Should I keep running my AC if it’s frozen?
No — turn cooling off and the fan to On so it can thaw. Running a frozen system can damage the compressor. Let it fully melt (a few hours) before we come out, and make sure the melting water drains and isn’t leaking onto floors or through the ceiling.
My outdoor unit isn’t running and it’s hot — what can I do right now?
Set your thermostat fan to On (fan only). It won’t cool, but circulating air with the furnace blower keeps the home more comfortable and even while you wait for the repair.
Can I add refrigerant myself?
We don’t recommend it — refrigerant is regulated, and needing it almost always means a leak that should be repaired. If you’re planning to replace the system soon, we can do an EPA-compliant top-off to get you through; otherwise we’ll find and fix the leak.
Why did my AC shut itself off?
Often a clogged condensate drain tripping the float safety switch, an overheating/airflow problem, or a tripped breaker. Check the filter and breaker; if it keeps happening, book a repair and we’ll find the cause.
How fast can you get out?
We offer same-day and after-hours emergency AC repair across the Salt Lake Valley. Call or text 801-960-5925.
Still not cooling?
Book a repair and we’ll diagnose the real cause, show you what we find, and fix it — tested before we leave. Proudly serving the entire Salt Lake Valley.