How To Check The Furnace Heat Exchanger? Quick Tips

Checking The Furnace Heat Exchanger

Furnace heat exchangers are critical for the heating system of homes and apartments. They can develop leaks, which can lead to health and safety issues. Regular visual inspections and tests are essential to detect any damage, including cracks or rust.

How To Check The Furnace Heat Exchanger
  • To start, turn off the gas and wait a few minutes
  • This makes sure all gas has dissipated, reducing the risk of combustion or explosion.
  • After that, remove the panels covering the burner chamber and inspect the primary heat exchanger.

Visual inspection may not be enough to detect cracks. Specialized equipment like a combustion analyzer or tracer gas detector can detect even the smallest leaks. This is done by analyzing flue gases on one side of the heat exchanger while introducing tracer gas on the other side.

Address any potential issues with the furnace heat exchanger immediately. Neglecting it could cause carbon monoxide poisoning and other severe health problems. Hiring an HVAC pro can help detect damages before they become significant problems.

According to industry standards, power burners in residential appliances must have flame roll-out switches near the burners’ ports. This shuts down the heating system if abnormal conditions occur, ensuring customer safety and peak performance. 

Checking your furnace heat exchanger is a must to guarantee safety and maintain a safe home.

Importance of Checking Furnace Heat Exchanger

As an HVAC pro, regular furnace maintenance is a must for efficient and safe heating. The heat exchanger is a key component of a gas furnace that needs attention. 

  • Neglect of inspection can cause gas leakage, carbon monoxide poisoning, and reduced airflow due to cracks or holes.
  • Take a look inside the furnace for signs of rust and condensation. If water droplets or dew are present, there may be a crack. 
  • Smoke or tracer gas test programs can detect leakage points.
  • Checking for cracks with a mirror or camera, be aware of flame pattern changes like flame rollouts or burner port burn marks. 
  • Always follow safety procedures when opening equipment to prevent combustible gas explosions.

ANSI Standards Home Appliances Safety Code 2019 Edition Section 10-1602(h) states if unsafe conditions exist due to cracked heat exchangers, corrective actions must be taken immediately.

Early signs of damage can save time and money on repairs. Don’t wait; contact an experienced technician today for furnace maintenance and a thorough heat exchanger inspection.

Visual Inspection of Heat Exchanger in Furnace

To ensure your furnace works well, regular maintenance is a must. A key part of this is inspecting the heat exchanger. It controls temperature and airflow and also expels toxic gases like carbon monoxide.

Here’s a helpful guide for what to look out for:

Inspect the heat exchangerCheck for rust or cracks along the surface
Check the blower fan outletClean or replace as needed.
Conduct combustion analysis Measure flue gas emissions with a combustion analyzer.
Test CO detectorsEnsure they are working properly
Look for burner leaksCheck the pressure drop in the burner port to detect any leaks

It’s best to get a professional to inspect your furnace if you don’t feel confident. This way, you can be sure your furnace is safe and efficient.

I carried out my inspection and noticed air flow issues. This made me call an HVAC technician who spotted a problem with some coils, preventing costly repairs later.

Checking Exchanger Flue Gas Side in Furnace

Checking the flue gas side of your furnace heat exchanger is essential for safety and to prevent any issues. To do so, here’s what you need to do:

  1. Turn off the gas and electrical power to the furnace.
  2. Remove burner(s) and inspect for rust, holes, or other damages.
  3. Look inside the heat exchanger with a mirror or camera with a light source. Check for cracks, distortion, corrosion, condensation, etc.
  4. Use a combustion analyzer to check for CO in the flue gases.
  5. Use a combustible gas detector to test for gas leakage.

Note any evidence of heat exchanger leaks or damages. It’s key to check the flue gas side of your furnace heat exchanger, some homeowners have experienced issues due to neglecting this step. 

So, make sure to get up close and personal with the burner and blower fan!

Checking Burner Port and Blower Fan in Furnace

When it comes to checking a furnace heat exchanger, burner port and blower fan are vital steps HVAC professionals must always remember. Here’s how to guarantee these parts are working properly and dodge potential issues in your HVAC system.

  1. Before beginning any inspection or maintenance task, switch off the power supply to your furnace.
  2. Use a flashlight or camera with a flash to inspect the inside of the burner chamber through the burner port, mostly located on either side of the furnace’s combustion chamber.
  3. Check for any rust, damage, or cracks on the heat exchanger surface surrounding the burner port.
  4. Examine the blower fan blades for dust buildup or physical damage.
  5. Make sure there are no obstructions or debris blocking the air filter or outlet of your furnace.
  6. Turn on your furnace again and observe its flame pattern using a combustion analyzer or tracer gas step method to detect gas leakage and probable CO emissions.

Moreover, remember to observe safety standards and manufacturer procedures when handling HVAC equipment. For example, certain models may necessitate taking off panels or accessing specific parts from distinct sides. Thus, note all modifications done during your inspection and take pictures as evidence.

I had a customer a few years ago who noticed his carbon monoxide detector going off often without any valid reason. After scrutinizing his heating system, we discovered various cracks on his secondary heat exchanger due to internal corrosion caused by condensation buildup over time.

We suggested replacing his entire furnace with a correctly sized one and gave him guidelines for proper AC maintenance. The customer was pleased with our services and happy that he could avert any potential carbon monoxide poisoning case in his home thanks to our technicians’ expertise.

Testing for CO and flame rollout switch: safety is not just an option, it’s important!

Testing for CO and Flame Rollout Switch in Furnace

Let’s get investigating! We must test for carbon monoxide (CO) and flame rollout switch as part of furnace maintenance. Safety standards require precise testing to ensure no one is in danger of CO poisoning. Here’s a table with the steps:

1.Inspect the primary heat exchanger for leaks, cracks, or damage that could lead to CO leakage or flame rollout.
2.Test the flue gas side of the heat exchanger with a combustion analyzer and check CO levels.
3.Run a heating cycle on the furnace to measure pressure drops across the burner ports and check if there’s positive pressure in the plenum.
4.Check the flame pattern with a mirror or camera to see if there are any combustion issues like poor ignition or low gas flow.
5.Activate each burner one by one and observe if there are any changes in gas leakage through holes or rust.

Only qualified technicians should do this as working on HVAC is risky. Don’t forget to use carbon monoxide detectors. Secondary heat exchangers are vulnerable to cracking from acidic condensation.

Examining Secondary Heat Exchanger and Coil in Furnace

It’s important to inspect a Secondary Heat Exchanger and Coil thoroughly. This involves looking at different points and parts of the HVAC system relevant to its performance, efficiency, and safety.

Check these crucial components:

  • Burner Chamber for Damage (ensuring proper ignition)
  • Flue Gas Side for Leaks (to prevent carbon monoxide poisoning)
  • Pressure Drop on One Side of the Exchanger (identifying issues on the other side)
  • Combustible Gas Leakage around Heat Exchanger Casing (evidence of cracked heat exchangers)
  • Flame Pattern across Burners using a Combustion Analyzer (correcting combustion issues, like low flame quality)

It’s necessary to check both the air and flue gas sides for heat exchanger leaks. Visual inspection isn’t enough, so use tracer gas tests or smoke tests. Adhere to industry installation standards and follow the ANSI/ACCA method. This makes sure all necessary interventions are made during furnace tune-ups or maintenance procedures.

Detect issues quickly, like cracks on heat exchangers, condensation, rust stains, etc. If significant material damage occurs, replace the entire furnace.

Neglecting furnace maintenance can lead to carbon monoxide poisoning – don’t take the risk!


Regular furnace maintenance is essential for the safety and efficiency of your heating system. Otherwise, you may get problems like leaks, carbon monoxide poisoning, and equipment damage. HVAC pros suggest annual inspections and tune-ups avoid these issues. During an inspection, the technician will check for any signs of damage like cracks, holes, rust, etc. If there’s damage, the technician will give you advice on how to fix it. In 2007, ANSI ventilation standards required power burner category furnaces to be sized based on airflow, not input capacity. And in 2011, condensing furnaces had secondary heat exchangers suggested to get higher efficiency.