Search Heco's growing HVAC knowledge library for repair symptoms, maintenance, parts, heat pumps, replacement planning, permits, rebates, commercial systems and more.
Heco HVAC · Experience since 2006 · California contractor license #1050351
Detailed homeowner guides explain safe checks, possible causes and when to request professional diagnosis.
Search what you observe—not what you think the failed part is. Several HVAC faults can produce the same symptom, and an on-site diagnosis is often needed before choosing a repair.
615 matching answers · page 15 of 21
Keep the contract/proposal, paid invoice, permit/final documents, model and serial numbers, warranty registration, maintenance records and any HERS or commissioning documents supplied for the project.
AFUE is Annual Fuel Utilization Efficiency, a seasonal rating that describes how much of the fuel input is converted into useful heat under the rating method. It does not by itself predict the home's utility bill.
Coefficient of Performance compares heat delivered with electrical energy used at a given condition. A COP above 1 means the heat pump is moving more heat energy than the electrical energy it consumes at that test point.
An ECM is an electronically commutated motor used in many newer furnaces and air handlers. It can support variable or programmed airflow more efficiently than older motor designs when properly set up.
A capacitor helps certain HVAC motors start or run by storing and releasing electrical energy. A failed capacitor can cause humming, hard starting or a motor/compressor that will not run.
The compressor circulates refrigerant and raises its pressure so the refrigeration cycle can move heat from indoors to outdoors. Compressor faults can be expensive and require professional diagnosis.
The evaporator coil is the indoor heat exchanger that absorbs heat from indoor air during cooling. It also removes moisture as water condenses on the cold coil.
The outdoor coil releases heat to outdoor air during air-conditioning operation. Dirt, debris and restricted airflow can reduce heat rejection and increase system stress.
The inducer moves combustion gases through the furnace venting path before and during burner operation. Its operation is tied to furnace safety controls and should not be bypassed.
A flame sensor confirms that the burner flame is established. If the control cannot prove flame, it shuts the gas valve for safety, which can cause burners to light and then turn off quickly.
An ignitor lights the burner fuel in furnaces that use electronic ignition. A failed ignitor can prevent heat even when the blower or thermostat appears to operate.
A pressure switch helps verify that the inducer and venting system are producing the expected pressure before allowing burner operation. Repeated switch faults require diagnosis of the whole vent/inducer path.
A limit switch protects the furnace from unsafe temperature conditions and may control blower behavior. Repeated limit trips can point to airflow, blower or overheating problems.
The reversing valve changes refrigerant flow direction so a heat pump can switch between heating and cooling. Valve or control faults can cause the unit to operate in the wrong mode or fail to change modes.
A float switch is a water-safety control that can shut the HVAC system down when a drain pan or condensate line backs up, helping reduce overflow damage.
A condensate pump moves HVAC drainage water when gravity drainage is not practical. If it fails or its safety switch opens, the cooling system may stop to prevent overflow.
A hard-start device changes the electrical starting characteristics of some compressors. It is not a universal fix and should be selected only after checking the compressor, capacitor, voltage and manufacturer guidance.
Temperature split is the difference between return-air and supply-air temperature under a specific operating condition. It is one diagnostic clue, but there is no single number that proves the system is correctly charged or sized.
Subcooling is a refrigeration measurement comparing liquid-line temperature with refrigerant saturation temperature at measured pressure. Technicians use it with manufacturer procedures to evaluate charge on applicable systems.
Rated-load amperage is a nameplate electrical value associated with compressor operation. Technicians compare actual current with manufacturer data and operating conditions rather than using the nameplate number alone as a pass/fail test.
Minimum Circuit Ampacity helps size the supply conductors, while Maximum Overcurrent Protection sets the maximum permitted fuse/breaker rating for the equipment. Electrical design should follow the nameplate and code.
They help identify equipment type, capacity, manufacturing information, compatible parts, warranty status and documentation. Photos of the nameplate are useful when preparing for service.
Often yes, but date-code formats vary by manufacturer. The advisor can identify a likely manufacture date only when it has a reliable manufacturer decoding rule and should label uncertainty clearly.
The control board coordinates thermostat signals, safety inputs and component operation. A board fault can mimic sensor or wiring problems, so diagnosis should confirm inputs and outputs before replacing it.
A zone damper motor opens or closes a duct damper in response to zoning controls. Failed actuators can cause rooms or zones to receive too much or too little airflow.
The supply plenum is the main air-distribution chamber connected to the equipment outlet before air branches into supply ducts. Leaks or poor transitions there can affect the whole system.
First determine whether the system is still producing normal cooling and airflow. Extreme heat raises building load, but a large or worsening temperature drift can also indicate airflow, coil, electrical or refrigerant problems; compare current behavior with what the system normally achieves.
Long runtimes can be normal near design conditions, especially for properly sized or variable-capacity systems. The concern is when comfort keeps deteriorating, airflow changes, icing occurs or energy use rises abnormally.
Afternoon solar gain and outdoor temperature can expose capacity, duct, insulation or airflow limitations that are less visible at night. The pattern is useful diagnostic information and should be compared with room orientation and system performance.
West-facing windows and walls receive strong late-day solar heat. HVAC design, shading, glazing, insulation and airflow all affect whether those rooms stay comfortable.
Equipment condition still requires professional evaluation. For regulations, rebates and efficiency guidance, Heco checks authoritative sources and identifies items that can change.
Tell Heco the symptom, equipment type, property type and location. We will help identify the next practical step.