HVAC problems & symptoms
You have a symptom.Let's find the cause.
Twenty-three of the problems Fresno homeowners actually call us about, each explained properly — what causes it, what you can check yourself, and when it needs a technician. Find yours below.
Stop and read this first
Four symptoms are not HVAC problems. They are emergencies, and the right first call is not to us.
You smell gas, or a rotten-egg odor
Leave the house immediately. Do not switch anything on or off, do not use a phone inside, and do not look for the source. Call 911 or your gas utility from outside or from a neighbor's.
A carbon monoxide alarm is sounding
Get everyone outside into fresh air and call 911. Carbon monoxide is colorless and odorless, and anyone feeling dizzy, nauseous or confused needs medical attention rather than a service call.
Smoke, or the smell of burning plastic
If you can see smoke, call 911. If it is an electrical burning smell with no visible smoke, shut the system off at the breaker and leave it off until someone has looked at it.
Someone in the house is unwell in the heat
Confusion, fainting, hot red skin or vomiting during a heat wave are signs of heat stroke. Call 911 first. The air conditioner can wait. Heat safety guidance here.
Everything else on this page is a repair problem, and most of them are smaller than they feel. Find yours below.
No cold air
The system is on but the house is not getting cooler.
AC not cooling
Running normally but the house never reaches setpoint. Several possible causes, and they are not all expensive.
Read the causesAC blowing warm air
Air is moving but it is not cold. Usually electrical, refrigerant or a frozen coil.
Read the causesAC won't turn on
Nothing happens at all. Start with the thermostat, the breakers and the float switch.
Read the causesOutside unit runs, no cold air inside
The condenser is going but nothing cold reaches the vents. Often airflow or the indoor blower.
Read the causesAC can't keep up in 105-degree heat
Fine most of the year, struggles on the worst afternoons. Often normal, sometimes not.
Read the causesRunning, but something is wrong
It cools, but the way it is behaving is not right.
Frozen or iced-up coil
Ice on the copper lines or the indoor coil. Turn cooling off before reading anything else.
Read the causesAC leaking water
Water around the air handler or staining a ceiling. Usually the condensate drain.
Read the causesAC short cycling
Starts, runs briefly, shuts off, repeats. Hard on the compressor and worth diagnosing.
Read the causesAC runs constantly
Never shuts off, even overnight. Sometimes expected in July, often not.
Read the causesAC tripping the breaker
The breaker is doing its job. Repeatedly resetting it risks real damage.
Read the causesNoises and smells
Something new that you can hear or smell.
AC making loud or unusual noise
Screeching, grinding, banging or buzzing. Each one points somewhere different.
Read the causesAC smells musty or burning
Musty usually means moisture. Burning means switch it off and call.
Read the causesFurnace smells like gas or burning
A gas smell is an emergency. Dust burn-off on the first cold day usually is not.
Read the causesFurnace making noise
Booming on ignition, rumbling, or a squeal from the blower.
Read the causesHeating problems
Fresno winters are short, but a furnace still has to work.
Furnace won't turn on
No heat at all. Thermostat, power, gas supply and safety switches first.
Read the causesFurnace blowing cold air
The blower runs but the air is cold. Often ignition or a tripped limit switch.
Read the causesFurnace not igniting or clicking
It tries and fails. Usually the igniter, flame sensor or a pressure switch.
Read the causesFurnace short cycling
Fires up, shuts down, tries again. Frequently airflow or a safety control doing its job.
Read the causesPilot light won't stay lit
Older systems. Usually a thermocouple, though it can indicate something more serious.
Read the causesComfort, cost and controls
Nothing is broken exactly, but something is not right.
Hot and cold rooms
One room never gets comfortable, or upstairs is unbearable. Usually distribution, not equipment.
Read the causesHigh summer electric bill
What is actually driving it, and which of those things are worth fixing.
Read the causesThermostat not working or blank
A blank screen is often batteries or a tripped float switch rather than the thermostat itself.
Read the causesSwamp cooler not cooling
Still common across the Valley, and it fails in its own particular ways.
Read the causesNot on the list
Describe it to us and we will tell you what it sounds like
Symptoms rarely arrive in tidy categories, and a lot of what we get called out to does not match anything you would think to search for. Call and describe what your system is doing. We answer questions on the phone for free, including from people who are not going to book anything today.
Once you know what it is
Three pages that answer what usually comes next.
Found your symptom?
A proper diagnostic, photos of what we find, and a firm price before anything gets touched.
Guidance on this page is general information and not a substitute for a professional diagnosis. In any emergency involving gas, carbon monoxide, smoke or a medical situation, call 911 first. California Heating & AC Repair is operated by Craftline Renovations, Inc. · CSLB License #999179 · Licensed and insured.