Repair help > Heating & Cooling Combined Unit repair > Heating & Cooling Combined Unit symptoms

Heating & Cooling Combined Unit: Why is my furnace not blowing hot enough?

Check the thermostat settings. If the furnace is fan is set to run constantly but the temperature setting isn’t set high enough to call for enough heat, adjust the thermostat. If the thermostat isn’t working properly, replace it.

If the thermostat is set properly and working as it should, check the air furnace air filter. A dirty filter will block air flow through the heat exchanger and air vents in your home. Replace the air filter if it’s dirty.

If these tips don’t help, then a problem with the furnace burners or the blower fan could be causing the heating problems. Have a service technician examine and repair the furnace if you’re not able to restore proper heating.

THESE REPAIRS MAY HELP SOLVE YOUR HEATING & COOLING COMBINED UNIT PROBLEM

Replace the HVAC system thermostat

The thermostat controls the heating and cooling system in your home. The thermostat senses the temperature inside your home and cycles the system on and off to maintain the set temperature. When your HVAC system control thermostat quits working, replace the thermostat.

Hvac system thermostat

Find the required part specific to your product.

March 3, 2022By Lyle Weischwill

How to replace a heating and air conditioning system thermostat

If the buttons on your HVAC system control thermostat don't work or if the display panel doesn't light up, the thermostat may need to be replaced. This DIY repair guide explains how to replace a thermostat in less than 30 minutes.

Repair difficulty

Time required

30 minutes or less

Replace the furnace air filter

Replacing the furnace air filter regularly to keep your furnace heating efficiently.

A dirty air filter inhibits air flow through the furnace heat exchanger and your home’s air vents. If your furnace isn’t heating as it should, check the air filter and replace it if it’s dirty.

To replace the air filter, shut off the furnace and allow the blower fan to stop if it’s running. Open the filter access door and pull the old air filter out. Position the new air filter according to the air flow arrow on the side of the filter and slide the new air filter into the filter housing. Close the filter access door. Turn the furnace back on to restore heating.

Furnace air filter

Find the required part specific to your product.

Symptoms common to all heating & cooling combined units

Choose a symptom to see related heating and air conditioning system repairs.

Why isn’t my air conditioner cooling well?

Dirty air filter, clogged condenser coils, low refrigerant charge, faulty compressor

Why is my furnace not blowing hot enough?

Thermostat problem, clogged air filter, burner failure

Why won’t my furnace burners won’t stay lit?

Dirty flame sensor, failed flame sensor, damaged burner, bad high limit switch

Why isn’t my air conditioner cooling?

Thermostat problems, bad compressor/condenser fan capacitor, lack of refrigerant, failed compressor

Why won't my air conditioner turn on?

Main causes: errant thermostat settings, lack of electrical power, clogged drain line, wiring failure, control failure.

Why won't my furnace turn on?

Main causes: Errant thermostat settings, lack of power, bad interlock switches, lack of exhaust ventilation, wiring failures.

Repair guides common to all heating & cooling combined units

These step-by-step repair guides will help you safely fix what’s broken on your HVAC system.

March 16, 2022

How to unclog the air conditioner drain line

By Sears PartsDirect staff

The condensate drain line for your central air conditioner can clog with mold and mildew. Water will back up and start dripping below the inside air conditioner unit. Follow the steps in this guide to unclog the drain pipe.

Repair difficulty

Time required

15 minutes or less

March 16, 2022