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Gas Furnace Troubleshooting Techniques

Electronic Control Board for an Electronic Ignition Furnace

Gas Furnace Troubleshooting Techniques - Electronic ignition for gas furnaces are the modern way for furnaces to light the main burners. Furnace technology has evolved from the standing pilot gas ignition systems. These furnaces continue to be used today, however, there are less standing pilot furnaces used today than yesterday.  When troubleshooting a system it is important to know which type of ignition system the furnace uses.

Gas Furnace Troubleshooting Techniques | Break It Down

Additionally, there are different types of Ignition systems. It is important to differentiate between the types of electronic systems before troubleshooting. We break it all down for you in this series article: “Troubleshooting an Electronic Ignition Gas Furnace“.

Troubleshooting any type of HVAC system does not have to be complex. The term “Electronic” generally intimidates people because electronics can be complex in any system. Take the independent parts and follow a few basic rules of troubleshooting you will find fixing anything becomes simpler. Here are a few basic steps to troubleshooting an electronic ignition gas furnace:

  • Is it an airflow-side problem?
  • It is a gas-side problem
  • Or an Electrical-side problem

Breaking it down even further, you can look for control problems or line voltage and component problems. Remember, safety is first.

Typically, in most gas furnaces, the control system will use 24-volts while the line side can use 120-volts or higher. You also have components that rely on specific pressures inside the furnace and gas supply. e.g., a component such as the pressure of the gas at the gas valve and the manifold. That will require tools and specific knowledge of how the system works.

  1. Always follow the manufacturer’s instructions especially for safety-related information.
  2. Understand the sequence of operation of the gas furnace.
  3. Break it down a little further. Understand how all the components work together in the system. That is a part of understanding the sequence of operation.
  4. Remember, any type of electronic device including electronic control modules and boards depend on two things, input and output. You must have input to get the proper output. If you have the proper input but are not getting any output, the problem is in the module or board. Before condemning the board or module make basic checks such as the power and ground.
  5. Learn basic troubleshooting techniques such as the hopscotch method. That will require you to understand how to read electrical diagrams. Pictorial diagrams are okay, but a ladder logic diagram is always best for troubleshooting. A ladder logic diagram will allow you to follow the sequence of operation for the furnace.
  6. Know how to use a multi-meter, including the basic settings on the meter for troubleshooting. Test instruments are important tools used to solve problems. Learning to use them properly is key to solving problems.
  7. Learn the Hopscotch method for troubleshooting circuits. That can especially be helpful with safety circuits.

If you run into a problem that seems to be unsolvable, take a step back. Take a break for a few minutes. Clear your mind and re-approach the problem, starting with the basics. I’ve been there and know some problems can be frustrating trying to resolve them. While troubleshooting a gas furnace problem requires skill and knowledge, it is not rocket science. If you have used your time wisely and learned as much as you can from a trade school to factory-sponsored classes, then you should have the knowledge and skill to figure it out.

Gas Furnace Troubleshooting Techniques | Conclusion

Some problems will be difficult to figure out even for the best technicians. These problems can be frustrating to find and repair. That is where you need a mentor to help you. Mentors can be someone in the company where you work, or it can be a manufacturers representative. A mentor can even be a manual or repair book for the furnace you are troubleshooting. When you run into a frustrating problem, take a step back, and take a break. When you return, start with the basics and focus on those. Turn to your mentor only after you have made certain that you have checked the basics first.

Gas Furnace Troubleshooting Techniques

High Performance HVAC

Gas Furnace Troubleshooting Techniques


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