Blizzard and Your Heating System
BLIZZARD AND YOUR HEAT (high efficiency furnaces)
Once again, we here are faced with another Winter storm. Some places are already referring to it as a Blizzard. Snow amounts will vary but there is a common thread. Your heating system.
If you have a high efficiency gas furnace you may not be aware that it had been vented in a different fashion. What is used is PVC piping (plastic) and generally is vented through the side of your home. This type of system has safety controls built into it. One such control is an air pressure switch. If your piping becomes obstructed, the air switch will tell the furnace to shut down. This air switch can sense things as small as a marble. Ice buildup or snow drift blockage would be the main cause of this situation. Keep all of your furnace pipes clean and unobstructed.
Another potential issue which is weather related would be "condensate blockage". These high efficiency furnaces also yield water as a byproduct of the combustion process. Generally it is drained to a sump pit, French drain (perimeter drain), or mechanically pumped (with the use of a condensate pump).
We have seen some instances where the condensate water is pumped outdoors. This is NOT a good practice. This water generally freezes up causing the pump not to work. Three things can happen. The first is that the pump finally burns out as it is constantly pumping against the icy obstruction. Secondly, the pump keeps trying and water overflows out of it leaving a mess all over the floor. The last thing that we will mention is that some pumps have an "overflow" or "safety" switch on them which shuts the furnace down if the water level in the pump is too high. If the pump doesn't work, the furnace will not too. We have seen a couple of times these pumps which were on other electrical circuits (which have been tripped). This too also had shut down the heating system. It is always best to have this condensate water pumped to a standpipe (like you would see on a washing machine) or into a "slop sink".
For those of you who have a high efficiency furnace in your attic, please check up on it periodically. Most contractors will NOT insulate your lines. WE DO. WE ALSO INSTALL HEAT TAPE ON THESE LINES. The potential for a high efficiency furnace water blockup is higher in an attic where temperatures can get into the freezing range. Should the right conditions occur, you will have a major flooded ceiling on your hands. At this point you may want to pick out a couple of skylight options.
To summarize this, keep mindful of your furnace vent piping and condensate drain lines during snow storms.
We hope this information will be found helpful to you. Many folks have paid good money and have gone without heat only to find that this situation could have easily been avoided.
Keep warm and safe thru this storm.
Dennis Kager (The Tin Man)