RV Forced Air Furnaces
Many people find that the
slender spaces beside their forced air furnace is ideal for storing such items as cookie sheets, cutting
boards, even paper or plastic bags. In addition to the obvious fire hazard, I would like to point out another
dangerous situation that could result from this practice.
The air intakes (for the fan that supplies return air to
the furnace blower) are located on either side and the top of the metal furnace housing. These air intake
slots draw air from the surrounding area and the blower fan forces this air past the sealed combustion
chamber in the furnace and on to the warm air duct work.
If this intake air flow is restricted, (with loose plastic
bags, aforementioned cookie sheets, etc.) the fan motor speeds up. (the same effect is observed when the
intake hose of a vacuum cleaner is plugged off).
There is a separate combustion air system, sealed from the
inside of the coach, that feeds fresh air to the burner assembly inside the furnace. This system draws in
outside air to allow the proper combustion of the fuel gas and then forces the exhaust products out again.
The fan for this system is powered by the same furnace motor that runs the blower, therefor it speeds up at
the same rate.
The increased air flow in the combustion chamber alters
the burn characteristics of the flame - producing a leaner, hotter flame. This overheating can lead to
failure of the furnace safety devices, damage to the electronic components of some models or in the worse
case a cracked combustion chamber. Exhaust products, including CARBON MONOXIDE, will now be forced into the
living area !!!! CO is odorless, colorless and extremely toxic - a silent killer.
Please check your furnace compartment for air flow
If you have any doubts or concerns regarding your
furnace's condition, have it inspected by a licensed, qualified RV gas technician.
A Carbon Monoxide Alarm installed in your unit is a
very inexpensive life insurance policy.
See also Troubleshooting the RV Furnace