Do you have a high efficiency furnace? Are you thinking of upgrading your technology? High efficiency furnaces are a little more complicated than their conventional counterparts, making troubleshooting a bit more complicated.
One of the main differences is with the heat exchanger technology. It uses a more sophisticated heat extraction process to exhaust the combustion gases. How do you know if you have a high efficiency furnace? You can usually tell by how the exhaust gas exits your home. If you have a small PVC pipe instead of a larger metal flue, you have a high efficiency furnace. You may also find two PVC pipes, one as an air intake, and the other the exhaust vent.
With high efficiency furnaces, if they have a weak flame or won’t ignite, there are several fixes that are relatively easy to complete.
Obstructed intake vent - if you have a blocked intake air vent, it will cause serious combustion problems in a high efficiency furnace. You can remove the burner compartment cover to ensure the combustion chamber is receiving proper airflow. You can also check the air intake pipe to ensure it isn’t blocked by leaves or a bird’s nest.
Improper exhaust gas recirculation - if you have a newer system and it hasn’t seemed to work right, it might be a problem with how the intake and exhaust vents were installed. It can create a short circuit, which allows exhaust gases to flow back into the combustion air intake pipe. Because the air supply flowing back into the system contains mostly water vapor, carbon dioxide, and carbon monoxide, it doesn’t have a proper oxygen level for proper function. Fixing the vents will fix the problem.
A clogged condenser drain - if the condensate drain is blocked by debris or frozen over, it causes it to drain improperly. The pressure switch may open and block the ignition process. The solution comes from fixing the problem with the condensation line.
A clogged flue vent - the pressure switch can also be tripped by an obstruction in the flue vent. While this is possible if leaves or other debris make their way into the PVC pipe, it can also be caused by improper installation. If it doesn’t slope correctly and have the proper horizontal run, it can collect condensation and trip the pressure switch.
Your high efficiency furnace may be one of the most important appliances inside your home. If you suspect any problems with its operation, have one of our professionals check it out immediately.