Sioux City and Siouxland · IA · NE · SD
The furnace stopped in a Siouxland snowstorm or deep freeze
A high-efficiency furnace draws air in and sends exhaust out through two plastic pipes, usually on a side wall or the roof. When drifting snow or frost closes one of them, a pressure switch keeps the furnace from lighting. It is a safety shutdown, not a failure, and it often happens on the coldest, windiest night.
Calls are answered 24 hours a day, 7 days a week.
What to look at outside
Find where the two white pipes leave the house. If snow has drifted over them, clearing it by hand, gently, can be enough; the furnace may restart on its next attempt. Do not knock ice off the pipe with a tool, and do not run a heat gun on PVC.
If the pipe ends are clear and the furnace still will not light, the problem is inside.
The other cold-weather fault: frozen condensate
These furnaces produce water as they run, and a drain line carries it to a floor drain or a pump. Where that line passes through a cold crawl space or garage, it can freeze. The water backs up, a switch shuts the furnace off, and it may show a pressure switch code on the board.
Why this matters in Siouxland
Sioux City averages 51 days a year when the high stays at or below freezing (NOAA 1991–2020 normals), so snow lies on the ground for long stretches and drifts against walls. Sergeant Bluff and North Sioux City have some of the newest housing in the area — half of it built after the mid-1990s — and a newer house is more likely to have a sidewall-vented furnace.
When to call instead
- The pipes are clear and the furnace still locks out
- Ice is forming inside the pipe, or water is leaking around the furnace
- The vent pipe has come apart, sagged or cracked
- You smell exhaust indoors — leave the house and call the gas utility first
Describe the problem and the age of the system. The operator checks who is taking calls near you.
(888) 217-3739