Repairing a cracked heat exchanger requires welding both sides of the crack to ensure that all leaks are stopped. In most small residential and commercial heating units, this is not possible. Cracks or holes in the heat exchanger of small residential furnaces and roofs cannot be repaired. On larger industrial equipment, some heat exchangers can be safely soldered to seal any leaks, but it's a difficult job to perform.
Repair requires double-pass pressure welding to seal leaks, which is not always possible due to access to the repair area. In commercial equipment and in buildings where there are no homes, gas heating equipment can be left running with cracks in the heat exchanger while waiting for replacement, as long as no CO is detected in the air. If the equipment loses CO, then the gas must be cut off immediately. We have used muffler cement as a short-term repair to reduce leaks until the system can be replaced.
Long-term repair for commercial heat exchangers is possible, but not very practical. It would cost more than a new unit or heat exchanger would cost. The metal in the heat exchanger is often too thin to be welded and impossible to access with welding equipment, even if the heat exchanger is removed completely. Depending on the severity of the crack, one of two tracking strategies can be employed.
If the crack is too large, or if it is accompanied by excessive amounts of internal corrosion, the heat exchanger will likely need to be replaced. However, small cracks can often be repaired by welding a metal patch over the damaged area. OK, I know what you're thinking. What are my options? And how much is this going to cost me? Unfortunately, there is no way to repair or seal cracks in a heat exchanger; therefore, repair is not an option.
Replacing the part can cost several thousand dollars and is only recommended if your HVAC system is newer and you have an existing warranty on the heat exchanger. You should be aware that you can expect quite high labor costs when replacing this item, even if it is covered by the original warranty. This is because, since the heat exchanger is located in the center of the furnace, the entire furnace must be dismantled to replace the heat exchanger. In view of the high cost, we recommend replacing the oven, especially if your current oven is 10 years old or older.
To ensure that the heat exchanger remains in good condition and is safe to use throughout the fall, HVAC experts recommend annual furnace maintenance. Unfortunately, it is possible that the valves that regulate the heat exchanger also wear out, contributing to cracking. The primary way to avoid problems with your heat exchanger or other HVAC components is to have an annual inspection and service performed by a qualified professional. In the worst case scenario, your cracked heat exchanger could be leaking carbon monoxide and your detectors wouldn't detect it.
With this technology, the technician can see holes, cracks, or corrosive damage inside the furnace. An oven that is too small for your home will cause airflow problems, leading to overheating. The primary heat exchanger is the area with the hottest flue gas and is located near the burner. Your oven might stop working if you're lucky, but most of the time, it'll still work even with a crack, allowing carbon monoxide to seep into your home.
This is only the second best case scenario; (the first best option is to get an annual maintenance of the furnace on your unit so that the technician notices the cracks before any problems arise). Depending on where the crack is located, the supply fan creates a positive pressure on the outside of the heat exchanger that can blow air inside the heat exchanger and into the flame. During the annual furnace tune-up, the HVAC professional will inspect your system for cracks before they become fatal. The secondary heat exchanger is where the flue gas undergoes greater heat exchange and water vapor forms.
It is vital that a professional furnace technician regularly inspects your heat exchanger for damage. . .
