Dwyer 460 Air Meter AND Draft Gauge

These Dwyer instruments are essential test instruments for anyone who diagnoses carbon monoxide (CO) and combustion problems on vented equipment.

For this November 2019 review, I want to highlight what this product comes with. First, it includes natural draft (drafthood) and induced draft (80%) equipment. Without it, you could easily misdiagnose a problem contributing to dangerous combustion readings.

With proper training, the draft gauge will tell you if adequate combustion air is available for the equipment and that no building pressure changes are interfering with equipment operation. In a few short steps, it can also tell you if a flue is restricted or undersized.

Contrary to popular belief, the draft gauge cannot verify proper equipment venting. You’ll need a combustion analyzer for that. The Dwyer 460 is an inexpensive and versatile solution for most draft pressure measurement applications. It comes with the following:

  • Carrying case
  • Dwyer 460 Air Meter / Draft Gauge
  • 4” length of pressure tubing
  • Various probes and accessories.

Draft pressure is measured in units called inches of water column (in. w.c.). The Dwyer 460 measures up to one-tenth of an inch of pressure (.10” w.c.) and is very sensitive to pressure changes. To get this feature in a digital manometer, you would have to pay hundreds of dollars.

Pressure tubing connects the draft gauge to a curved metal probe that is inserted into the flue for draft measurement. A small white ball inside the draft gauge moves up and down freely to indicate the draft pressure reading on the gauge’s black scale.

Occasionally, the inside of the gauge may get damp from flue gas and must be cleaned so the ball moves freely.

If this November 2019 review piques your interest, and you want to learn more about the Dwyer 460, go to the NCI Store at ncilink.com/Dwyer460.

by David Richardson, Curriculum Development and Instructor, NCI