Air Conditioner Not Cooling? Here's What Yous Should Troubleshoot.

Our experts explicate how to repair the most mutual causes of central air conditioning service failures.

Introduction

Our experts shows yous easy DIY solutions for the most common key air conditioning repairs. You'll exist up and running sooner and will salvage the expense of a service telephone call.

Tools Required

Materials Required

  • Capacitor
  • Compressed air
  • Condenser fan motor
  • Contactor
  • Fuses

DIY Air Workout Service Repair

When central ac service fails during a rut spell, y'all may take to wait days for an HVAC repair technician or an ac contractor to bear witness up, and you lot'll probably pay at least several hundred for the repair. Merely if you're comfy working around electricity and are willing to spend about $fifty on parts, you can probably repair your air workout service yourself in near 2 hours and save about $225 on parts markup and labor.

Nosotros talked to local HVAC repair technicians to get their best do-it-yourself Ac fan repair and maintenance tips. These tips will assistance you with the nearly common "depression cooling" and "no cooling" problems. You lot'll demand an inexpensive multimeter, a voltage sniffer, an assortment of insulated screwdrivers and a socket set.

If these Air conditioning repairs don't piece of work, at least you've covered the most mutual failures, and your service guy can concentrate on finding the more elusive problem. Plus, with the new parts, you lot'll likely add together years of breakdown-free air workout. Here's how to offset.

Why Is My Air Conditioner Not Cooling the House?

Make Certain the Problem Isn't the Furnace

Fix your thermostat to AC fashion and lower the temperature setting. If the furnace fan kicks in, the problem isn't in the furnace. If the fan doesn't run, try resetting the furnace circuit breaker. If the fan even so won't outset, call a pro — the fixes shown hither won't piece of work.

Next, cheque the exterior condensing unit. The compressor (which sounds like a refrigerator) and fan should exist running. If non, follow the troubleshooting and repair procedures shown here.

Caution: Plow Off the Power

Turn off the A/C and furnace breakers in the principal electric panel before pulling the outdoor disconnect or removing the condensing unit'southward access console. Then use a voltage tester on the wires coming into the contactor to make sure the power is really off.

Air conditioning Doesn't Work? Purchase Parts

The Air-conditioning contactor (relay) and outset/run capacitor(s) (run across illustration beneath) fail most ofttimes and are inexpensive. And then it's a safe bet to purchase and install those parts correct away, especially if your air conditioning service unit is older than five years. The condenser fan motor can also neglect, merely it runs about $150 — hold off buying that unless you're certain that's the culprit.

To buy replacement parts, find the nameplate on the condensing unit of measurement (not your furnace). Jot downwardly the make, model and serial number (or have a photograph). Get the parts at an appliance store, furnace dealer or online.

Projection step-by-step (8)

Step 1

Learn the Anatomy of a Primal Home Air Conditioner

Central habitation air conditioner service systems consist of two major components: a condensing unit of measurement that sits outside your firm, and the evaporator coil (ofttimes referred to as an A-gyre) that sits in the plenum of your furnace or air handler. The refrigerant in the A-coil picks up the heat from your dwelling house and moves it to the outdoor condensing unit. The condensing unit fan blows exterior air through the condensing coil to remove the heat. The condensing unit houses the three parts replaceable by a DIYer: the AC contactor, the start/run capacitor(s) and the condenser fan motor. The condensing unit also houses the compressor, but merely a pro can replace that. The A-gyre has no parts that tin exist serviced by a DIYer.

diagram of a central home air conditioner

Stride 2

Shut Off the Ability

  • Open the electrical box next to the condensing unit of measurement and pull the disconnect block straight out.
  • Cheque within the box with a voltage sniffer to make certain the power is really off.

air conditioning service shut off the power

ⓘ

Footstep 3

Clean the Condenser Coils

  • Aim your garden nozzle upward into the top of the condenser scroll to remove the crud buildup under the chapeau.
  • Piece of work all the style effectually the scroll. Then aim the nozzle down and affluent the debris downwardly the coil fins.
  • Adjust the nozzle to a gentler stream and shoot water straight into the coils to flush out any remaining debris.

clean condenser coils on air conditioner

Step iv

Exam the Fuses

Many disconnect blocks comprise two cartridge fuses. Bank check them earlier you proceed with repairs. A blown fuse is a sign of a failing office within the condensing unit. So don't but replace it and retrieve y'all've solved the problem. Instead, supersede the parts, install new fuses, and burn upwardly the unit. If information technology blows again, call a pro—y'all've got more serious problems.

How to Check Fuses In the Disconnect Block

  • Ready your multimeter to the lowest Ohms scale and touch the red and blackness leads to contrary ends of each fuse.
  • If you get a numerical reading, the fuse is proficient.
  • A zilch, a minus symbol, or an infinity symbol (∞) indicates a blown fuse.

air conditioner fuse block pull out

Step v

Inspect the Within of the Access Panel

Follow the electrical conduit from the house — that's where you'll find the access panel. With the ability off, remove and store the access-panel retaining screws and remove the panel. Before yous replace any parts, bank check for rodents' nests or evidence of chewing on wires and electrical connectors.

If you notice broken wires or chewed insulation and tin safely handle electrical repairs, discharge the capacitor first. And so repair the wires and clean out the nest. Otherwise, phone call a pro.

How to Belch a Dual Showtime/Run Capacitor

  • Remove the capacitor from the retaining subclass.
  • So touch an insulated screwdriver between the HERM (or "H") terminal and the COMMON (or "C") terminal.
  • Practice the same between the FAN (or "F") terminal and the "C" final.
  • On single-mode capacitors, just make a short between the 2 terminals.

inspect access panel in air conditioner

Step half-dozen

Replace the Get-go/Run Capacitor(s)

All air-conditioning service units have at least one capacitor. The capacitor stores electricity and releases it during compressor and condenser fan startup to requite both motors an extra jolt of ability. And it smooths out voltage fluctuations to protect the compressor and condenser fan motor from harm.

Capacitors can dethrone slowly, providing less startup ability over time. Or they tin fail in an instant. Gradual capacitor failure can get unnoticed for a long fourth dimension, stressing the compressor and condenser fan motor windings, resulting in their early failure. Since capacitors are cheap, it pays to proactively replace yours nigh every five years.

How to Replace a Capacitator

  • Accept a photo of the wires before disconnecting annihilation (you may need a reference later on).
  • Discharge the stored energy in the erstwhile capacitor.
  • Utilise needle-nose pliers to pluck i wire at a time from the old capacitor and snap it onto the corresponding tab of the new capacitor. The female person crimp connectors should snap tightly onto the capacitor tabs.
  • Jerk each connector to see if it's tight. If it's not, remove the connector and bend the rounded edges of information technology and then it makes a tighter fit on the tab.
  • When you lot've swapped all the wires, secure the new capacitor.

Alert: Belch the capacitor earlier disconnecting wires or removing it from its bracket.

Install the new air conditioner capacitor

Stride 7

Supersede the Air-conditioning contactor

An Air-conditioning contactor is a $25 mechanical relay that uses low-voltage power from the thermostat to switch 220-volt high-amperage current to the compressor and condenser fan. AC contactors can wear out and are at the top of the list of common air-conditioning service failures. Even if your Air conditioning contactor is working, it pays to supervene upon it every 5 years or so. Unscrew the sometime AC contactor before removing the wires. Then motility the wires to the new unit (Photo six).

HVAC Troubleshooting Photograph 6: Bandy out the Air conditioning contactor

  • Yank a connector off the one-time contactor and motility it to the same location on the new role.
  • Tighten the connectors where needed.
  • Secure the new contactor in the condensing unit of measurement.

replace the ac contactor

Footstep eight

How to Test Your Repairs

  • Reinstall the access panel and disconnect block.
  • Turn on the circuit breaker and furnace switch, then prepare the thermostat to a lower temperature and expect for the Ac to start.
  • The compressor should run and the condenser fan should spin.
  • If the compressor starts but the fan doesn't, the fan motor is most likely shot.
    • Shut off the power and remove the screws around the condenser cover.
    • Lift the comprehend and remove the fan blade and motor.
    • Reinstall the blade and secure the cover.
    • Then repower the unit of measurement and come across if the fan starts.
    • If it doesn't, you lot've given information technology your all-time shot—information technology'south time to call a pro.

Replace the fan motor in air conditioner

Be Patient at Startup

AC units and thermostats have built-in delay features when they're close downwardly and so repowered. The delay can be equally long as ten minutes. And, if y'all've subscribed to an energy-saving device from your local power utility, the unit tin can take even longer to reset. If y'all've installed the parts shown and reinstalled the disconnect block, repowered the circuit breaker, turned on the switch at the furnace, moved the thermostat to AC mode and lowered the temperature beneath the indoor temperature, and the unit of measurement doesn't burn down up afterward thirty minutes, information technology'due south time to call a pro.

Originally Published: May xx, 2022