HVAC Fault Code Lookup

It depends on the equipment. Most gas furnaces flash the code on an LED on the control board, behind the blower compartment door. Some modulating furnaces, such as the Rheem R96V, show it on a small seven-segment display instead. Communicating systems (Carrier Infinity, Bryant Evolution, Lennox iComfort and Comfort Sync) show the code and a short description on the wall control. Ductless and ducted split systems usually show a letter-and-number code such as E3 or F5 on the indoor unit display.

Count the flashes between pauses. On most brands the count is the code, so four flashes is code 4. Carrier, Bryant and Payne 58-series furnaces use two digits: short flashes are the first digit and long flashes the second, so three short and three long is code 33. Codes change between board revisions, so compare against the diagram printed inside the access panel of your unit.

It depends on the brand, so the color alone is not a diagnosis. On many furnaces a green LED shows normal status, while a red or amber LED that blinks in a repeating count is a fault code: count the blinks between pauses and search that count here with your brand, for example Goodman 3 flashes or Trane 4 blinks. A light that stays solid red or flashes without a pause is a separate code on Goodman, Amana and Trane boards.

Fix the cause first, then reset. Many controls clear a lockout on their own: Rheem R96V boards lift a soft lockout after one hour, and Carrier 58-series boards reset a limit lockout after about three hours. You can also switch the power off at the furnace service switch and back on. If the same code returns, the fault is still there. Do not keep resetting flame rollout, limit or gas valve codes: have a licensed technician check the furnace.

Because a code only means something on the board that generated it. On Carrier Infinity equipment 41 is a blower motor fault, while on another manufacturer's board the same number can point at something unrelated. On communicating systems the same number can even differ between the indoor unit, the outdoor unit and the zoning control. That is why every result here names the brand, the equipment family and the component it applies to.

Codes that name the blower directly: Carrier Infinity and Bryant Evolution 41 (blower motor fault), 44 (cannot communicate with the blower) and 15 (blower lockout); Lennox 201 (lost communication with the indoor blower motor), 202 (motor size mismatch), 292 (blower will not start) and 295 (blower overheating); Rheem and Ruud 60 and 61 (blower fault, motor can or cannot run). High limit codes, such as Carrier 13 and 33, Lennox 250 and 274, and four flashes on Goodman, Amana, Trane and Arcoaire furnaces, are airflow faults: a failing blower motor is one cause, and so are a dirty filter, a dirty blower wheel and restricted ductwork. Before you order a part, run the checks in our ECM motor testing guide or the multimeter test.

Almost always because the restriction behind it is still there. A blower motor that trips on thermal overload or hits its torque limit is usually pushing air through a dirty filter, a dirty blower wheel, a plugged coil or undersized ductwork. Replace the filter, clean the wheel and coil, and measure total external static pressure against the blower table before you fit a new motor, otherwise the new one fails the same way. On two-piece ECM motors the control module fails far more often than the motor itself, so test it separately (ECM 2.3, 2.5, 3.0 and EON guide; for one-piece motors, the X13 guide). On Lennox and Rheem equipment the horsepower of the replacement must match the original exactly, or the control throws a size-mismatch code (Lennox 202, Rheem d6). If a motor you bought from us shows a code, see what to do when a new motor shows an error code.

No. A fault code tells you which safety or sensor the control tripped on, not which part failed. A high limit code means the furnace got too hot: that can be a dirty filter, a closed damper, a slipping blower wheel, a failing motor or a bad limit switch. Use the code to narrow down where to look, then measure. For symptom-based checks, start with our blower motor troubleshooting guide. Anything involving gas, flame rollout, a cracked heat exchanger or line voltage belongs to a licensed technician.

Fault codes vary between manufacturers, product lines and board revisions, so no single list covers everything. Check the diagram inside your unit's access panel and the manufacturer references on this page. If you still can't place it, send us the code with the model and serial number from the rating plate and we'll look it up. Not sure what equipment you have? Decode the rating plate with our HVAC serial number lookup.