Troubleshoot Your HVAC System

When your heating or air conditioning  system is not working properly, it can be frustrating. You want to avoid paying a lot for repairs, but you want your home to feel comfortable again. At Andy Lewis we understand your frustration, and we want to save you time and money by offering advice for troubleshooting your HVAC system. Of course we are ready and willing to come to your home to diagnose and repair your system, but we also want to help you avoid paying for unnecessary service calls. The following is a list of common HVAC problems and possible solutions.

Click on the topic below to find out more about possible causes and fixes.


Thermostat warning light is on or flashing

The inside temperature never reaches the temperature I set the thermostat to

Some rooms are warmer or cooler than others

Low Air Flow

Indoor Unit Leaking Water

Circuit breaker trips repeatedly

Pilot light goes out

Air conditioner not cooling

Heat Pump Iced Up in Winter

Heat pump/Air Conditioner iced-up in summer

Heat Pump running constantly/doesn’t shut off

Outdoor Unit Won’t Turn On

Outdoor unit is making unusual or loud noises

Steam coming from outdoor unit


Thermostat warning light is on or flashing

When your heat pump is in normal operation (not emergency heat mode) and the red warning light is flashing or on, it usually means the outdoor unit has shut itself off or is “locked out.” The indoor unit may continue to run, because the outdoor unit is where the problem lies. When the outdoor unit shuts itself off, it sends a message to the thermostat, which causes the light to come on or blink.

Possible cause:

  • Outdoor unit blocked by something or covered in ice.

Action to be taken by homeowner:

  • Remove snow or ice from outdoor unit.

If this does not correct the problem, you should contact your HVAC experts at Andy Lewis.


The inside temperature never reaches the temperature I set the thermostat to

If you set your thermostat to a certain temperature, but it never seems to reach that temperature, it is most likely due to the thermostat itself. It may be that your thermostat needs to be calibrated. This can easily be fixed by an HVAC specialist, but it seems that this solution is only temporary, as many people find that the same fix is needed soon afterwards. The best solution is to have a digital thermostat installed. Digital thermostats are very accurate and some are even programmable to save you up to 30% in energy costs. Call Andy Lewis to upgrade to a digital thermostat.


Some rooms are warmer or cooler than others

Uneven heating and cooling is a common problem with heating and air conditioning systems. Some rooms are nice and warm in the winter, others are chilly. Some rooms get comfortably cool in the summer, others are stuffy. Air flow has a lot to do with this problem. Dirty filters, closed vents, and ductwork issues can impede air flow, causing uneven heating and cooling. Home insulation is also a factor.

Steps you can take:

  • Check or replace filters.
  • Make sure all vents are fully open.
  • Seal any drafty places like around windows and doors.
  • Use sun and shade to your advantage by opening or closing curtains or blinds.

If none of this helps and rooms are still drastically different in temperature, call Andy Lewis.


Low Air Flow

Does it seem like there is not enough air coming out of the vents in your home? Does it seem to be lower air flow than usual? It’s possible you have a problem with your HVAC system, but it could be something you can correct yourself.

*Air cleaners and high efficiency filters can slow air flow to your HVAC system.

Try the following solutions first:

  • Check filters for build-up of dirt, dust, pollen, or pet hair.
  • Make sure all vents are open and clear.
  • Dampers should be open. Make sure the handle is in line with the duct, not turned 90 degrees (which is closed position).

If all of these things seem to be in order and you still have air flow issues, it may be a more serious problem. Contact your HVAC expert for advice.


Indoor Unit Leaking Water

If there is water coming from the indoor unit of your HVAC system, you need to correct it as soon as possible to avoid water damage to your home. Water around the indoor unit means your system is leaking, not draining properly, or making excess condensation. Condensation can form on the evaporator coil and suction line if they are not properly insulated. If the necessary insulation is missing or leaving part of the coil or line exposed, more condensation collects on it, which can drip onto the floor. In some situations the coil may ice up, and when the ice melts it will leave a puddle on the floor. If the condensation drain is blocked it can cause pooled water. In the worst case, your system could be leaking refrigerant. Both air conditioners and furnaces can leak water.

Try the following:

  • Make sure the insulation is properly installed on the coil and suction line.
  • Be sure the condensation pump is plugged in.
  • Check to be sure your floor drain is not clogged.


Circuit breaker trips repeatedly

Occasional circuit breaker trips are possible, especially in cases of electricity overload during peak usage hours. But if your HVAC system repeatedly causes the circuit breaker to trip, you may have a problem. Electricity is not something to work on yourself due to the high danger. If the breaker is tripped, simply flip it back the other way. If it comes back on, it may have been a fluke. If it happens again, you may have a more serious issue that requires a professional. Electrical issues can pose a fire risk, and HVAC systems run at high voltages.

For safety sake, call Andy Lewis and one of our technicians will come to check it out.


Pilot light goes out

If you have an older furnace with a standing pilot light, it may go out at some point during the heating season. But if it happens more than a time or two, it may indicate a problem. Some people choose to turn off the pilot light when the heating season ends to save fuel (just a small amount of gas or propane is needed to keep a pilot light lit). It is a good idea to know how to relight a pilot light in case it does go out.

Steps for lighting a furnace pilot light:

*If your furnace has instructions for lighting the pilot, follow those first.

1. Turn off furnace, boiler, or water heater at thermostat or power switch.

2. Locate the gas valve and turn knob from on or off (depending on where it was) to pilot position.

3. Hold down red button, which sends gas to the pilot burner.

4. At the same time, hold match to pilot burner. (Just follow the small pilot tubing to end.) Sometimes a long match is needed. You can use needle nose pliers to hold match.

5. On some equipment you may need to move a small metal door or panel for access.

6. Light the pilot but do not let go of button.

7. Continue holding button for 60 seconds.

8. Let go of button. Pilot should stay lit. (If not, you need to schedule service.)

9. Turn gas valve knob back to the on position.

10. Turn on appliance. Turn up thermostat. Main gas should light.

11. Put back metal cover if your system had one.


Air conditioner not cooling

The most common summertime air conditioner problem is failure to cool. There are many possible causes for an air conditioner that isn’t properly cooling your home. The good news is that it may be a simple fix.

Check the following things first:

  • Check to see that the thermostat set to “cool.”

  • Make sure the thermostat is set to a temperature that is below room temperature.

  • Check to see that the Power is on to the indoor unit.

  • Look in your electrical box for a tripped circuit breaker (one that is flipped the opposite direction from the other breakers. If they are labeled, one should be designated to the HVAC system.) Flip it back the other way to the on position.

  • If the above are all in place, the unit should be running.

  • If not, look for a reset button (probably red) for the outdoor unit. Push the reset button.

If none of these steps have corrected the problem, call Andy Lewis for service.


Heat Pump Iced Up in Winter

It is common to see ice on your heat pump in the winter. In cold weather you may see frost or a little ice on the coil. But if your entire heat pump unit is covered with ice, including the top and inside, you may have a more serious problem. To avoid system failure and excessive energy usage, a professional HVAC technician can determine the problem and correct it. It could be that the defrost cycle isn’t working properly.

The problem may be caused by:

  • Water dripping onto unit from a leaky gutter
  • Weather conditions like freezing rain
  • Outdoor unit may be blocked by snow, leaves, or other debris
  • The outdoor unit may have settled too low into the ground


Heat pump/Air Conditioner iced-up in summer

If you see ice on your air conditioner or heat pump in the summer, it is definitely not working properly. There should never be ice on the indoor or outdoor unit, or any other part of your air conditioner or heat pump in warm weather. Turn off your AC immediately.

The problem may be caused by:

  • Thermostat set too low
  • Blocked filter
  • Vents blocked or closed, including supply and return vents
  • Windows open while AC is running

If none of these are the cause, call Andy Lewis.


Heat Pump running constantly/doesn’t shut off

During the winter or summer if your heat pump is constantly running it can mean a variety of different things. But it does mean that your heat pump isn’t working correctly. First check a few things to see if there is a simple solution:

  • Make sure your thermostat is set to heat or cool and that the temperature setting is above or below the room temperature.
  • Check to see if the breaker is tripped.
  • Listen for the outdoor unit. Is it running?
  • Check the filters for dust or dirt build-up.
  • Look for snow or ice build-up on the outdoor unit.

If none of those checks provide a solution, consider the following possible causes:

  • Poor home insulation.
  • Cold return temperatures from an attic or basement.

If either of these are the cause, or if nothing you try corrects the problem, you should consult your HVAC professional at Andy Lewis.


Outdoor Unit Won’t Turn On

If the outdoor unit of your heat pump or air conditioner isn’t turning on, there could be a simple solution. This is a common problem with HVAC systems.

Possible causes:

  • Thermostat is not properly set
  • Circuit breaker has tripped
  • Blown fuse
  • Emergency switch is off
  • Outdoor reset button is tripped

If none of these seems to be the problem, it’s time to call an HVAC specialist.


Outdoor unit is making unusual or loud noises

It is perfectly normal for your heat pump to make some noise during the winter time. Refrigerant liquid flows back and forth throughout the system when switching from heating to cooling mode and also for the defrost cycle. A “wooshing” sound like the sound of water through pipes may be heard when the refrigerant is flowing. It may last for a few seconds, but this sound is normal.

Abnormal sounds would be a metal “clanking” sound, perhaps indicating that the fan blades are hitting something. If you hear this sound, turn off your system and call Andy Lewis.

Some causes you may be able to correct yourself:

  • Ice interfering with fan blade
  • Some other outside obstruction interfering with fan blade

Causes that require an HVAC specialist:

  • Loose parts vibrating against each other
  • Refrigerant piping may be strapped too tight causing vibration


Steam coming from outdoor unit

Heat pumps have a regular defrost cycle that run occasionally to remove build-up of ice due to weather conditions. This ice build-up lowers the efficiency, so the heat pump takes care of this on its own. This cycle often causes heat pump owners, especially those who are new to this type of system, to think there is a problem because they see steam coming from the system and mistake it for smoke. The fan stops running during the defrost cycle as well, causing further confusion to the homeowner because the combination of steam and a stopped fan makes them think the fan motor has burned up. It also makes a louder than usual sound during the defrost cycle. All of this is completely normal and you have nothing to worry about.

The only action required on your part:

  • Regularly check to see that no debris or ice is blocking the outdoor unit.

If for some reason your heat pump does not resume normal function in a few hours, then it may be necessary to call an HVAC professional at Andy Lewis.