Troubleshooting Basics

HVAC equipment is complicated and only professional technicians should attempt service or repair. However, if you experience a problem, there are a few possible “quick fixes” that can be safely attempted. On all HVAC equipment, if it is not working at all, first check the fuses/breakers in the main electrical panel then check to see if there is a switch or disconnect on the indoor unit. If it is an outdoor unit that is not working, check the disconnect located near the unit. If you are unable to determine the problem at this point, you will need to call for service.

If the fan is running but there is no heat, press the reset button (it should be red) on the furnace. It will attempt to fire. If furnace fires, your problem may be solved. Do not attempt to press the reset button multiple times, as this can flood your furnace with oil and cause a possible fire hazard. Before calling for service, make sure the oil tank has oil in it. Many oil furnace issues can be avoided by following a simple maintenance schedule, including annual cleanings.

If furnace has electronic ignition (no pilot) and is not heating, turn the thermostat off and wait 30 seconds. After that time, turn the thermostat back on. If the furnace does not resume heating, check the furnace to make sure the gas is on. If natural gas furnace has a pilot, you may turn off the furnace and relight the pilot. Turn the furnace back on. If it heats for a short period of time and quits, check to make sure all of the supply ducts are open, the return is free and clear of obstructions such as furniture and the ducts are clean.

If the furnace runs on liquid propane (LP), make sure your tank is reading at least 30%. If not, call your gas provider.

If you have no hot water from your faucet, first check to see if the water heater pilot is lit. If it is lit, make sure the adjustment knob is not set on “vacation” and the cut-off knob is not set to “pilot.” Change the settings if either of those readings are showing. If you relight the pilot and check the knobs and still do not have hot water, call a service technician.

When it is cold outside and your heat pump is set in “heat” mode, it is normal for your heat pump to develop ice on the outdoor unit during wet and/or very cold conditions. The unit will defrost itself, however if the ice develops with significant thickness and the unit does not defrost itself, you will need to call for service. Only in an absolute emergency should you attempt to defrost the unit yourself by running it in cooling mode until it defrosts. This can cause damage to the unit and should be used in emergency only.

When using a heat pump in cooling mode, and the outdoor unit freezes, you should check the filter’s cleanliness, check the return grills for obstructions, and make sure the supply registers are open. If you find any of the above are the problem, you can turn the unit off with the fan on for 6-8 hours. After the unit is completely defrosted, you may resume normal operation. If the unit freezes again, you will need to call for service. Your serviceman will be unable to work on a frozen unit, so be sure it has defrosted before he arrives.

See “Heat Pumps” in cooling mode.

Mode Comfort & Air Quality always suggests that you contact a professional service technician for any heating/cooling problem. While this troubleshooting guide contains helpful hints, you may wish to contact a professional to avoid creating further damage to your equipment.