HVACopediaTroubleshooting guides
What to check when there is no error code: no heat, no cooling, noise, short cycling, low flow and other symptoms. 467 guides, each with likely causes and a check-in-order procedure written for technicians.
Air conditioner54 guidesAir handler9 guidesBoiler26 guidesCombi boiler4 guidesElectrical15 guidesFurnace97 guidesGas fireplace58 guidesGeneral44 guidesHeat pump49 guidesMini-split9 guidesRefrigeration85 guidesTankless water heater17 guides
Have a code instead?
Look it up in the error code library, with causes and test steps for each brand.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.