Concentric Vent Cap Sizing for Screens

Concentric Vent Cap Screens

Concentric vents are often used in ventilation systems for high efficiency boilers, furnaces and hot water heaters. Unlike standard vent termination hubs, concentric vent terminations have the appearance of a small pipe extending out from a cone or saucer. Unfortunately the exhaust pipe extending out from the cone is prone to entry by birds and insects, which is why this opening must be protected by a suitable cap with screen.

On this page we will help those with concentric vents to determine the correct cap needed to guard the exhaust vent. The most common concentric vent models are the 2″ CVENT-2 and 3″ CVENT-3 models, which CVC series concentric vent caps are designed to protect as pictured above. Both concentric vents are easily identified by not only their cone shape, but from the words “do not block intake” embossed on the cone.

Concentric Vent Exhaust Pipe Dimensions

Using a tape measure or rule, measure the outside diameter of the pipe extending out from the concentric vent’s cone, If the outside diameter of the exhaust pipe is 2-11/16″, then the CVC-I2 and CVC-R2 should be used seasonally to provide all-season vent protection. If the outside diameter of the exhaust pipe is 3-3/16″, the CVC-I3 and CVC-R3 should be used seasonally to guard the exhaust vent from infiltration events by animals (birds, mice, etc.) and insects (bees, wasps, etc.). Please view the image below to view the points of measure and dimensions.

Concentric Vent Exhaust Pipe Dimensions

Important: If your conical vent does not have the words “do not block intake” embossed on it, with large lettering, it’s possible your vent is terminated with a reducer. Please see our exhaust vent accelerator page for additional information.

Please note we do not recommend using a vent screen on a concentric vent’s intake. Please visit our concentric vent intake screen page for additional details.


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