1. Sarrera
This manual provides essential information for the safe and effective installation, operation, and maintenance of the Carrier HK42FZ018 Furnace Control Circuit Board. This board serves as the central control unit for your furnace, managing various functions to ensure proper heating operation. Please read this manual thoroughly before proceeding with any installation or service.
2. Segurtasun informazioa
OHARRA: Instalazioak, doikuntzak, aldaketak, zerbitzuek edo mantentze-lanak desegokiek kalteak, kalte pertsonalak edo bizitza-galera eragin ditzakete. Instalazioa eta zerbitzua instalatzaile kualifikatu batek, zerbitzu-agentziak edo gas hornitzaileak egin behar ditu.
- Always disconnect electrical power to the furnace before installing or servicing the control board. Failure to do so can result in electrical shock or death.
- Erabili babes pertsonaleko ekipamendu (BPE) egokia, segurtasun betaurrekoak eta eskularruak barne.
- Handle the circuit board by its edges to avoid damage from electrostatic discharge (ESD).
- Ensure all wiring connections are secure and correctly matched according to the furnace wiring diagram.
- Ez saihestu segurtasun-gailurik.
3. Produktua amaitu daview
The Carrier HK42FZ018 is an upgraded replacement furnace control circuit board designed to manage the operational sequences of compatible Carrier furnaces. It integrates various functions including ignition control, fan operation, and safety monitoring.

1. irudia: Carrier HK42FZ018 Furnace Control Circuit Board. This image displays the full circuit board with various components including relays, resistors, capacitors, and terminal blocks. Key labels such as "24VAC COM", "NEUTRALS", and "HEAT COOL" are visible, indicating connection points and functions.
Key components on the board include:
- Terminal Blocks (TB1): For connecting furnace wiring, including power and control signals.
- Erreleboak: Control various furnace components like the blower motor and igniter.
- Fuses (F1): Provide overcurrent protection for the board and connected circuits.
- LED adierazleak: For diagnostic purposes, indicating operational status or fault codes.
- Jumpers (e.g., JW5): Used for setting specific operational parameters, such as fan off-delay times (e.g., 60, 100, 140, 180 seconds).
4. Instalatzeko jarraibideak
This procedure outlines the general steps for replacing a furnace control board. Always refer to your specific furnace model's service manual for detailed wiring diagrams and safety precautions.
- Deskonektatu energia: Turn off all electrical power to the furnace at the main service panel or circuit breaker. Verify power is off using a voltage probatzailea.
- Kontrol-panelera sartzeko: Ireki labearen sarbide-panela dagoen kontrol-panela aurkitzeko.
- Dokumentuen kableatzea: Before disconnecting any wires, take clear photographs of all connections. Label each wire and its corresponding terminal on the old board. This step is critical for correct reinstallation.
- Deskonektatu kableak: Kontu handiz deskonektatu kable guztiak kontrol-taula zaharretik.
- Kendu taula zaharra: Desmuntatu kontrol-panel zaharra labearen xasisetik. Kontuan izan nola finkatu zen (torlojuak, klipak, etab.).
- Instalatu plaka berria: Mount the new Carrier HK42FZ018 control board in the same location and orientation as the old board. Ensure it is securely fastened.
- Konektatu kableatzea: Refer to your photographs and labels to connect all wires to the corresponding terminals on the new board. Double-check every connection for accuracy and security. Pay close attention to the 24VAC COM, NEUTRALS, and HEAT COOL terminals.
- Set Jumpers: Configure any jumpers (e.g., fan off-delay) on the new board to match the settings of the old board or the requirements of your furnace model. The image shows jumpers for 60, 100, 140, and 180 seconds for OFF-DELAY.
- Itxi sarbide-panela: Konexio guztiak egiaztatu ondoren, itxi eta finkatu labearen sarbide-panela.
- Berrezarri boterea: Turn on the electrical power to the furnace at the main service panel.
- Proba funtzionamendua: Initiate a heating cycle to verify proper furnace operation. Observe the LED indicators for any fault codes.
5. Funtzionamendua
The control board automatically manages the furnace's operational sequence based on thermostat calls for heat or fan operation. Upon a call for heat, the board initiates the igniter, opens the gas valve, monitors flame presence, and activates the blower motor once the heat exchanger is sufficiently warm. It also controls the fan for continuous operation if selected at the thermostat.
LED adierazleak: The board features an LED (visible in Figure 1) that provides diagnostic feedback. Consult your furnace's specific service manual for a list of LED flash codes and their meanings.
6. Mantentzea
The Carrier HK42FZ018 control board is designed for reliable operation and generally requires no routine maintenance. However, periodic inspection of the furnace system is recommended:
- Ensure the furnace filter is clean to prevent excessive strain on the blower motor and other components.
- Keep the area around the furnace clear of obstructions to allow for proper airflow.
- During annual furnace servicing by a qualified technician, the control board and its connections can be visually inspected for any signs of wear or damage.
7. Arazoak
If your furnace is not operating correctly after control board installation, consider the following common troubleshooting steps:
- Potentziarik gabe: Check the furnace circuit breaker and ensure it is in the "ON" position. Verify the furnace access panel is securely closed, as some panels have safety interlocks.
- No Heat/Fan: Review all wiring connections to ensure they are secure and correctly matched. Refer to your documented wiring and the furnace's wiring diagram.
- LED Fault Codes: Observe the diagnostic LED on the control board. A flashing pattern indicates a specific fault. Consult your furnace's service manual for the interpretation of these codes.
- Blower Runs Continuously: Check the thermostat settings to ensure the fan is not set to "ON" continuously. Verify the fan off-delay jumper settings on the control board.
- Pizte-hutsegitea: Ensure the gas supply is on. Check for proper igniter operation and flame sensor cleanliness.
Arazoa konpontzeko urratsek ez badute konpontzen, gomendagarria da HVAC teknikari kualifikatu batekin harremanetan jartzea diagnostiko eta konponketa gehiago egiteko.
8. Zehaztapenak
| Marka | Garraiolari |
| Modelo zenbakia | HK42FZ018 (Replacement for) |
| Produktuaren neurriak | 8 x 6 x 10 hazbete |
| Elementuaren pisua | 12.28 ontza |
| Potentzia Sarrera | 24VAC, 50/60Hz (as indicated on board) |
| Pizte Sistema | Automatic Ignition System (as indicated on board) |
9. Bermea eta Laguntza
This Carrier control board is typically covered by a manufacturer's warranty. For specific warranty terms and conditions, please refer to the documentation provided with your purchase or contact Carrier customer support directly. Keep your proof of purchase for warranty claims.
For technical assistance or support, please contact a qualified HVAC professional or the Carrier customer service department.





