This flue pipe obviously terminates in the attic. It was from a heater in Santa Rosa. If you look carefully, you will notice that the wood immediately adjacent to the cap is scorched. Instead of the attic, this flue pipe from Forestville terminated in the foundation crawlspace under the floor. Parhaps I am naive, but I am always amazed at the new methods that people find to try and kill themselves with.The heater flue pipe for this Petaluma "heritage" home terminated at a second story balcony adjacent to the master bedroom.A flue pipe should always slope up away from the heater or water heater. In this case, the combustion exhaust gases can be trapped and can "backvent" into the interior of the home on the other side of this wall, potentially resulting in carbon monoxide poisoning of the inhabitants.Under a roof overhang is not a good idea either. This one was from Monte Rio.The next three photos are from a forced-air furnace located in a Petaluma home. As you can see, they are corroded through to the exterior. The condition of the interior surfaces would be even more obvioius. Forthuantely, this was located in the garage and not overly likely to poison someone immediately. However, the possibility still exists and needs to be corrected.The next two pictures show a newer double-walled B-vent in a Petaluma attic that is connected to an older Transite vent pipe that is enclosed within a wall. The issue is that Transite is not a currently approved flue pipe and there is no approved method of attaching the new to the old. Transite is a cement-asbestos pipe that was commonly used in this area in the 1950s, but use may have extended from the mid 1940s until the 1960s. Really should be replaced with an approved B-vent.Looking up into a forced-air furnace heat exchanger. The burners would be behind the camera. These next two photos show rust on the metal of the heat exchanger. The interior of a heat exchanger is difficult to view and rarely photographed as the chamber is generally too narrow for a camera.Of particular interest are the "dimples" in the upper reaches of the compartment. These are spot-welded together and when they fail, they can leave a hole through which the combustion exhaust gases can contaminate the household air supply, which would be flowing along the other side of this. The first in a series of five photos from a single furnace installation in Rohnert Park. One of the most dangerous furnace installations I have seen.Foil tape was wrapped around the connections of the flue pipe; however, the tape is not approved for this use and should be removed. Also, the double-walled flue pipe needs free airflow that would normally enter at the open bottom. A greater problem exists in the last photo. The interior of the blower compartment of this Rohnert Park furnace was pretty dirty, but the question was how did it get insulation and the other debris? The next three photos have the answer.Looking up alongside the return air plenum (above the blower in the previous picture), the underside of the roof sheathing can be seen, but it looks like the plenum (air goes back to the furnace from the interior of the home via this chamber) is not closed at the top. Sure enough, in this photo looking up into the compartment above the blower, you can see the roof sheathing. Worse yet, the flue pipe from the final photo in this series terminates within this plenum. A flue pipe should not be run through the ducting system.This flue pipe was probably the worst that I have seen. In this final photo of this Rohnert Park home, the flue pipe terminated inside of the return air plenum. As a result, whenever the blower was on, combustion exhaust gases were being circulated throughout the house via the ducting system.Disconnected ducting found in Petaluma. While you might think that this is only a waste of energy, dirt, rodents and contaminants can get into the ducting at this point. This duct should not only be reconnected, but all of the connections should be examined and the interior of the ducting cleaned.Crushed ducting in Petaluma. Crushed ducting will restrict airflow and allow some rooms to be uncomfortably cool. However, a larger problem is that the ducting is resting on the soil where it can get wet and allow water into the interior of the duct. Ick!Older sheet metal ducting will leak at connections and can become disconnected or dislodged very easily. If sheet metal ducting is present, each seam should be secured and sealed to minimize air loss. It is a good idea to have older ducting cleaned as well. The insulation on this ducting in a Santa Rosa attic is allowing heat to escape into the attic. While the air is not actually leaking out, the lack of insulation will allow heat loss. The outer sheathing on the "wire-flex" ducting from the 1980s and 1990s did not hold up well in the heat. The damage to this Santa Rosa attic ducting was likely caused by rodents. Any contaminated ducting should be replaced. The scorch marks on this horizontal furnace in Santa Rosa indicate improper operation and age. The Consumer Products Safety Commission recalled some brands of horizontal furnaces that had been the cause of fires. If you have a horizontal furnace, a heating contractor should take a look at it.Viewed down from the attic through the wood framed chase. I really should not have been able to see this disconnected flue pipe. A draft stop should have been present at the top of the chase. Ok, so I make fun of homeowners who do goofy things, but here is a professional installation of a furnace and it is necessary to dismantle the flue pipe to change or clean the filter. Who thought of this one? Someone who wants to make more money every time the filter needs to be replaced. Now, you need to be able to get to the furnace in order to service it. In this case, access will be difficult due to the lack of a work platform in front of the appliance as well as the framing that is in the way. Whiule duct tape is great for NASCAR and Apollo 13, it is not reliable enough for ducting. The adhesive dries out and will eventually fall off. Today, many heating contractors use giant cable ties (zip ties) that cinch around the duct and hold them in place. Other methods use a rubber sealant.
Heating Photos
I consider the heating system to be the forgotten stepchild of a home.  Many gas forced-air furnaces suffer from minimal or no maintenance, and as a result, perform poorly or even unsafely.  In this age of higher energy costs, regular maintenance of a furnace is paramount.  Furnaces are apparently designed to last 15-20 years.  Few, if any are replaced at that time.  Most furnaces in existing homes are as old as the home itself, many are twice as old as their expected design life.  I will periodically run across a furnace that is 60 or 70 years old.  While often functioning, these appliances are inefficient and potentially unsafe.  A surprisingly common, defect that I find is loose, disconnected and damaged ductwork, which will significantly affect the cost of heating a home or other building.  It is relatively easy to seal connections in ductwork, but replacement of  damaged or inefficient ducting should be entrusted to a licensed heating contractor.
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