I have a Empire CIBV-20-30 natural gas fireplace I installed in my home. It has 5.5 ft of vertical stack and 19 inches of horizontal stack going through the wall. I used the specified 4" bvent.

When it gets below 35 degrees outside the fire place will not vent. I have tried a horizontal cap, turning the pipe down 45 degrees, 90 degrees, and adding 2 ft of vertical outside. Nothing seems to work. It burns until the temp limit switch shuts it down and no venting happens. When its 40 degrees out or above it vents beautifully.

Any suggestions?



Gas , oil, and wood need air( oxygen) to burn , then the flue gas can be vented. So , let in some air, A K A -open a window. When I lived in a colder climate , I always provided an air inlet , generally a duct pipe from outside to near the furnace, or fireplace in this case. Newer furnaces are generally required to have an ejector fan on the exhaust vent because newer houses are well sealed and it is difficult for a natural draft to work. The lower the outside temperature , the more the problem.

  • I did try cracking a window open. It didnt seem to help. The air intake is fixed from the factory. I also tried cracking the front door open. Also did not help. Maybe a draft inducer on the draft hood will help – Tony Talerico Oct 27 '19 at 18:42

I'm only a novice on these things, but it sounds like you may need to clean your Blower Wheel of dust, hair and lint. Also, your Air Shutter may need a cleaning. A schematic can be found here fireplaceparts.com/

I couldn't see any mention of it, but you may need a double-wall piping. Or, need to go all of the way to triple-wall for temperatures below 40...if you already have double-wall. As, double-wall can get heated enough to cause outward draft and kill the inward drawing.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.