🔧 1. AC Is Blowing Warm Air (No Cooling at All)

If your air conditioner is blowing warm air, the system has completely lost its cooling capability. This usually indicates a failure of one of the critical components.

---

Main Causes

1. The outdoor unit (condenser) is not running at all

This is the most common electrical issue in central AC systems.

Symptoms:

• outdoor fan not spinning
• compressor silent — no humming, no vibration
• only the indoor blower runs
• no “click” from the contactor when the system turns on

Typical electrical causes:

• blown fuse in the disconnect box
• failed contactor — burnt or stuck contacts
• failed dual capacitor — prevents both the fan motor and compressor from starting
• bad hard-start kit or failed start relay
• damaged or corroded wiring
• control board surge damage after a thunderstorm

If the outdoor unit doesn’t start, cooling will not begin, no matter how long the system runs.

---

2. No refrigerant (leak in the system)

A refrigerant leak causes pressure to drop.
As a result:

• the evaporator coil cannot absorb heat
• airflow remains warm

Most common leak locations:

• evaporator coil
• flare fittings
• copper line set (vibration wear)

---

3. Frozen evaporator coil

When the coil is covered in ice, it cannot cool air.

Causes:

• clogged air filter
• restricted airflow
• dirty evaporator coil
• low refrigerant

Symptoms:

• weak airflow
• warm air
• ice on the large copper suction line

---

4. Compressor failure

One of the most expensive and serious breakdowns.

How to recognize compressor failure:

• outdoor fan runs, but there is no cooling
• loud humming or clicking when the compressor tries to start
• compressor won’t start even with a hard-start kit
• excessively high LRA (locked rotor amps)
• compressor overheats and shuts off on thermal overload

Common reasons for compressor failure:

• overheating due to a dirty condenser
• old age (10–15 years is typical for Colorado)
• short cycling
• running the system with low refrigerant

---

Solutions

• Restore power, inspect fuses and contactor
• Replace the dual capacitor
• Repair damaged wiring
• Perform leak test, repair and recharge
• Defrost and clean the evaporator coil
• Full compressor diagnostics (amperage, resistance, load)
• Repair or rebuild the outdoor unit

---

❄️ 2. AC Is Cooling, But Not Enough (Weak Cooling Performance)

In this situation, the AC does cool but not well enough — the house warms up during the day, temperature rises above the thermostat setting, or cooling is very slow.

This is a problem of efficiency, not a total system failure.

---

Main Causes

1. Dirty outdoor condenser coil

If the condenser is clogged with cottonwood, dirt, grass, or construction dust, it loses up to 40% of its cooling capacity.

Symptoms:

• hot air blowing out of the outdoor unit
• outdoor fan running, but home not cooling
• higher electricity bills
• compressor overheating

Colorado has a lot of cottonwood and dust — this problem is extremely common.

---

2. Poor airflow inside the home

Reasons:

• weak blower motor
• clogged or crushed ductwork
• closed or blocked supply vents
• dirty evaporator coil

Symptoms:

• low airflow
• cold air at the vent, but not enough of it
• uneven cooling between rooms

---

3. Low refrigerant (leak in the system)

A refrigerant leak causes pressure to drop.
As a result:

• the evaporator coil cannot absorb heat
• airflow remains warm
• the system may freeze up

Most common leak locations:

• evaporator coil
• flare fittings
• copper line set (vibration wear)

---

4. Overheating or weakening compressor

A compressor that is wearing out still runs, but produces less cooling:

Symptoms:

• slow cooling
• house barely cools during the day
• cooling only improves at night
• long run times

This is a “weak compressor,” not a fully failed one.

---

Solutions

Deep cleaning of the outdoor condenser

Blower motor diagnostics

Compressor performance test

Perform leak test, repair and recharge