10 COMMON FURNACE 
PROBLEMS AND WHAT TO DO
Gas furnaces are generally strong machines with long expected service life, and most units over 20 years old are still on the job. Because gas heating has a long history, established manufacturers have mass-produced gas-fired furnaces. This helps keep the costs of brand-new units relatively low and simplifies installation. Below are 10 common furnace problems and what to do:
Though symptoms may vary according to individual make and model, the list of typical furnace problems is familiar to any experienced technician. Here are ten common furnace problems and some typical causes a professional HVAC technician will investigate during his diagnosis.
Orange Flame
Neglected Maintenance
Many furnace problems, including malfunctions and breakdowns, can be avoided with regular preventive maintenance. The annual furnace tune-up includes:
- A checklist of close-up inspection of all functions to detect any developing issues. This could become even more costly and inconvenient as well as manufacturer-recommended preventive maintenance procedures.
- Annual preventive maintenance by an approved HVAC contractor is usually required under the terms of an effective warranty upon purchase.
Increasing Operating Costs
If your monthly gas expenses increase yearly during the winter seasons, your furnace may be consuming too much fuel. The aging of your furnace could be the cause of declining efficiency. Wear and tear from repetitive heating, and cooling cycles gradually affect critical components, as with most appliances. In a gas furnace, though moving parts are relatively few. https://www.socalgas.com/save-money-and-energy/rebates-and-incentives
Poor Heating Performance
Oftentimes, when the furnace is running longer and not heating the home efficiently, the issue is low airflow. Correct supply and airflow volume are necessary to facilitate efficient use of your AC unit to heat or cool your home. The BTUs (British Thermal Units) measure the energy needed to heat your home based on square footage. Install a new air filter for your system. Changing the filter at least every other month to help with airflow and keep your BTUs as consistent and low as possible.
If performance doesn’t improve, contact your local qualified HVAC contractor. Another potential airflow issue is a failing blower motor and problems with ancillary or support systems. Leaky ductwork that could allow hot air to escape into the attic, crawl space, or other unconditioned zones.
Ignition Problems
A faulty ignition system could be the cause for a furnace burner that simply will not light when the thermostat signals it. Older gas furnaces and some new ones incorporate a standing pilot light to ignite the main burner. If the pilot flame goes out frequently—often caused by a defective thermo-couple — the burner won’t ignite. In those cases, the pilot flame may need to be lit manually to keep the burner working until your HVAC professional can determine a more permanent solution.
Defective Thermostat
Mercury-style thermostats are manual units incorporating metallic springs that weaken and contact switches that become extremely unreliable over a long period. This may cause the thermostat to actuate at the wrong temperature—or not at all. These thermostats can also cause the furnace to run for overly long cycles. It is important to consider upgrading to an electronic programmable thermostat as soon as possible. A programmable thermostat can save enough in lower operating costs to pay for itself after the first year when utilized properly.
Strange Noises
Some sounds are common as a furnace cycling on and off. The muffled, if not annoying, noises of metal ductwork expanding and contracting as it heats and cools are normal. Squeaky or screeching sounds when the furnace cycles on. However, this usually indicates a failing blower motor or bearing. Unusually loud roaring sounds when the burners are lit suggest a combustion problem. This should be reported to a qualified HVAC contractor immediately, as it may risk the safety of your home and residents.
Furnace “Short Cycles”
Failure of an internal component is one probable cause for a unit to cycle on and off rapidly throughout the day. A flame sensor built into the unit may not be properly sensing the burner flame and turning the unit off prematurely. A professional HVAC servicer may need to clean the flame sensor and, if the problem isn’t resolved, replace the sensor unit.
Another cause of short cycles may be a furnace overheating and triggering the high-temperature limit switch that shuts off the burner. An overheating furnace is a safety hazard that requires prompt, professional service.
The furnace Is an Improper Size
“Size”, in this case, refers to the BTU output of the unit. The furnace output of a given model must be the proper size to accommodate the BTU requirements of the home. Furnaces can waste energy and underperform in providing indoor comfort. When they are inaccurately sized for the home, whether they are oversized or undersized. Resolving sizing issues requires upgrading to a new furnace after getting a sizing calculation performed by a qualified HVAC contractor to accurately determine the home’s heating load determined by the BTU.
Some Rooms are Too Cold, Other Rooms Too Hot.
Closing heating vents in certain unused rooms can lower heating costs. As well as upset the careful airflow balance throughout the entire system. This can cause rooms nearer to the furnace to be too hot, while rooms furthest away may be too chilly. So, closing these air vents doesn’t save money as expected. The furnace runs frequent and unnecessarily long cycles. Also burns more gas to compensate for airflow and heating imbalances.
Defective Heat Exchanger
A damaged or deteriorating heat exchanger is usually discovered by an HVAC technician and is a critical safety component. The heat exchanger keeps system airflow separate from deadly carbon monoxide gas produced in the combustion chamber. A cracked or corroded heat exchanger usually means the furnace is unsafe and must be shut down. Replacing it in an older unit is usually not a financially viable option. The heat exchanger is the most expensive single component in the furnace. Upgrading to a new furnace is highly recommended.
For qualified service to resolve furnace problems that impact your household comfort and your monthly expenses, contact AC Dave Heating & Air (661) 270-1961 for all your HAVC needs.