Chimney Draft Test

Measuring by waiving an instrument at the fireplace opening or chimney top is in my opinion a waste of time inaccurate misleading not useful.

Chimney draft test.

How to measure diagnose and repair inadequate draft smoky fireplaces or heaters how chimney location affects chimney draft and performance how to diagnose poor chimney draft for a smoky fireplace woodstove or heating boiler furnace 18 things to check if your chimney has bad draft or your fireplace is smoky how to correct inadequate chimney draft questions answes about. A good draft is vital for a good combustion. To properly check the vent draft you want to first close all of the windows and doors in the house. A tall chimney gives more draft.

It is possible to measure fireplace chimney draft by making a suitable test opening into the chimney flue not a usual practice and not something i recommend. The chimney diameter should never be less than the diameter on the appliance flue outlet. We consider a normally good draft to be between 10 20 pa 1 2 mm vc. Diagnose correct chimney draft performance problems with this simple draft test.

When a chimney is shared by multiple appliances the appliance with the smallest btu input rating shall be tested first and remaining appliances tested in order of increasing input rate. If the draft is insufficient it can be a solution to build a taller chimney. Thus doubling chimney height increases draft by 41 percent. Chimney too short draft is proportional to the square root of the height of the chimney assuming that other factors don t interfere.

Learn how to perform a smoke test with the help of this guide from chimney specialist barney dorman. How to improve the draft on a metal chimney when a chimney for a fireplace or wood stove is functioning normally a hot fire creates an updraft that sweeps waste gases from the fire up through it. The chimney creates the draft not the appliance. Induced draft heating systems shall be checked for spillage at the base of the chimney liner or flue.

Watch this and other related films here. There are lots of confusing technical explanations of how chimneys work and how a simple draft problem can result in some very uncomfortable issues.