Dangerous Cracked Heat Exchangers in Furnaces | Heating Safety
You can see the rust holes up near the sheet metal plates in this heat exchanger
Dangerous Cracked Heat Exchangers in Furnaces - Everyone wants heat when old man winter arrives in the fall. Many times we take it for granted. When the temperature falls all we have to do is go to the thermostat and turn the heat on. Usually, this is not a problem. We turn the thermostat on and the heat comes on. When we first turn the furnace on we have a slight burning odor that comes from the system. (more…)
The residential steam boiler is still alive and well despite the fact that some HVAC professionals refer to it and the steam boiler profession as the dead man’s club. However, there are not a lot of HVAC boiler technicians or HVAC companies that specialize in steam boilers because there are not a lot of steam boilers used for residential and light commercial applications. 
This picture shows furnace flue condensation problems. This problem is caused by hot gases cooling too quickly in the flue. As the hot gasses cool, the moisture in the gases condenses and starts dripping back down the flue. Typically, there is a combustion issue or bad flue design. 