We purchased a brand spankin' new high efficiency gas furnace in the fall of 2002 - the WeatherMaker 9200. We didn't get the 500, the 1000 or even the 2000 model. We got the 9200! It slices, it dices and it heats our home with a 91.2% to 95.5% AFUE rating (Annual Fuel Utilization Efficiency). This unit has a microprocessor that will shut down the heating unit if the filter becomes too clogged or if the flue pipe becomes blocked. Without the shutdown feature, a blocked flue pipe means that deadly carbon monoxide gas can fill your home and possibly kill you.
On the morning of Presidents' Day, 2003, we woke up to find two feet of snow on the ground and a cool inside temperature of 59 degrees. Our beloved WeatherMaker 9200 wasn't running, and we were nervous first-time parents stuck at home with a 4 month old baby.
Regardless of the skill level or experience, the typical man's reaction to a broken device is to pop open the hood. We don't really know what we're looking for most of the time, but we have to look. I removed the cover from the WeatherMaker 9200, and it was one of the 1 out of 10 times that I could actually see what was wrong. I saw icey slush in this little glass window where I should have seen a blue flame.
Snow had completely covered the flue, and the safety feature shutdown the furnace. Some of the snow worked its way down the flue to create the slushy mess inside. The flue sticks out over the back of our garage roof, and the flue was covered by the 24 inches of snow plus snow drifts from snow blowing off our main roof.
I dug my ladder out from underneath two feet of snow near our shed, and I climbed onto the garage roof to shovel around the flue. I turned the power off to the furnace, and I used a hair dryer to melt the slushy mess. I turned the furnace back on, and a mini crisis was averted.
I also left a message with our furnace people - Belair Engineering, but with two feet of snow on the ground, they're technicians weren't going to be making calls that morning. When I did finally speak to someone at Belair Engineering the following day, I was told that they had six similar calls from customers with the same problem. I was also told that the installation specifications for the WeatherMaker 9200 require a short flue that can be no more than 18 inches above the roof line.
Flue pipe on the garage roof
Storms the size of the Presidents' Day storm are infrequent in Bowie, so I felt comfortable that I could deal with the problem whenever one of those rare storms comes along. Most of the time I can shovel from the ladder without having to step on the roof, but I do occasionally have to climb on the roof. I proactively shoveled around the flue back in December when Bowie received over 20 inches of snow, and I did it again last night around 10:00pm before I went to bed.
Our furnace has two blowers, the first one blows exhaust up the flue pipe, and the larger one blows hot air through the vents. When the furnace first kicks on, the burner ignites, and the smaller blower starts blowing the exhaust up the flue pipe. When the temperature is warm enough, the larger blower starts circulating the air through our house. This is the eighth winter that we've had the WeatherMaker 9200, and I'm familiar with the sounds of the different blowers.
I was lying awake in bed at 2:00am this morning, and I heard the first blower turn on. But this time, it kept running and running, and the larger blower never kicked on. I ran downstairs and popped the hood. There was no blue flame! I cursed. I cursed again - and again - and again. My cursing had no effect - the flame still didn't come on. I didn't see an icey slushy mess in the furnace this time.
Shortly after 2:00 in the morning, I was back up on the ladder removing snow from around the flue pipe. The wind was blowing directly off the main roof toward the garage roof, and a snow drift had just barely covered the flue pipe. I went back inside. The flue pipe blower was still running, but no blue flame. I went back out on the roof with a flashlight. The flashlight slipped from my hands, and it rolled off the roof. I cursed again. I retrieved the flashlight, and inspected the pipe - no blockage. I went back inside. It still wasn't working. I thought maybe there was snow/ice blocking the pipe where I couldn't see. I dug out our space heater, and my wife started using a hair dryer to blow hot air on the first section of the flue pipe. Eventually we decided to re-start the furnace. We waited anxiously as it started back up, and after 30 seconds - blue flame! The whole ordeal lasted about two hours.
While I was outside, there were two occasions when I saw a flash of light in the distance, and I heard a mini explosion - most likely the sound of an electrical transformer blowing. One seemed to come from the Whitehall neighborhood and the other from the Chapel Forge neighborhood. We later lost power for about 5 seconds.
And now for the visual snow accumulation report...