By-Pass Sizing Calculator

Often with zoning systems a By-Pass is needed to relieve excess air when only a small zone or number of small zones cannot deliver the required air flow thru the HVAC System. A by-pass is often ducted back into the return air or into non-critical, common conditioned temperature areas such as entry ways, hallways, basements, etc.

Select your Maximum Total System Cubic Feet per Minute (CFM), then enter the CFM of your Smallest Zone to calculate the type of By-Pass Damper you require.

Note: If the By-Pass CFM amount is 30% or less of the Total System CFM, No By-Pass is required.

CFM of Smallest Zone *

By-Pass CFM

SPRD08

The By-Pass Damper you are looking for is SPRD08.

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SPRD09

The By-Pass Damper you are looking for is SPRD09.

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SPRD10

The By-Pass Damper you are looking for is SPRD10.

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SPRD12

The By-Pass Damper you are looking for is SPRD12.

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SPRD14

The By-Pass Damper you are looking for is SPRD14.

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SPRD16

The By-Pass Damper you are looking for is SPRD16.

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RDM18-SPC

The By-Pass Damper you are looking for is RDM18 w/SPC.

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RDM20-SPC

The By-Pass Damper you are looking for is RDM20 w/SPC.

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ZDSM2020-SPC

The By-Pass Damper you are looking for is ZDSM2020 w/SPC.

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ZDSM2420-SPC

The By-Pass Damper you are looking for is ZDSM2420 w/SPC.

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ZDSM3024-SPC

The By-Pass Damper you are looking for is ZDSM3024 w/SPC.

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Price

Trolex Corp. & Zonex Systems’ Leadership

Trolex Corporation acquires Zonex Systems

Randolph, NJ. – Trolex Corporation announced its acquisition of California based Zonex Systems. Trolex, and its New Jersey based subsidiary ZONEFIRST’s President Dick Foster stated, “The acquisition of Zonex Systems brings together the two oldest manufacturers of zoning dampers and zone control systems in the industry. The parallel paths of both companies, their histories, one being on the east coast, the other on the west, one being residentially focused, the other being commercial, both being started by our fathers and the complimentary product offerings makes this a very synergistic combination.”

Zonex Systems President Jeff Osheroff stated, “After so many years working with my Dad and seeing the great potential zoning continues to offer in the HVAC Industry, I’m exceedingly happy to partner with an industry veteran, Dick, Trolex and ZONEFIRST to provide the industry’s most comprehensive mix of zoning and control solutions for the residential and commercial controls markets.”

Both companies will continue to operate independently as plans progress for integration.