From the counter: a real question from a wholesale branch, and how we answered it.
The question
The HVAC manager at a wholesale branch in southern Alberta had a customer with a new range hood and a familiar problem: every time the hood ran, the house went negative. The customer had seen a packaged make-up air damper from a range hood brand and asked whether Hoyme made something equivalent.
It is one of the most common calls we get. A tight modern house has nowhere for exhaust air to come back in from, so a powerful hood either starves or pulls replacement air down a flue or through the gaps around doors and windows.
What we recommended
Instead of a single packaged unit, we put together three parts the branch already stocks or can get:
- A 6 inch HAC motorized damper on the make-up air duct, 24 Vac, Canada/USA CSA certified.
- A current sensor on the range hood circuit, supplied by the contractor, which tells the damper when the hood is running.
- Optionally, an ADP-0241-05A relay adaptor to run the furnace fan whenever the hood runs, so incoming air is actively distributed through the house instead of pooling near the inlet.
We specified the damper as power close (part number HAC-0610-OPC). It is held closed while the hood is off and springs open when the hood runs, and it also springs open if power is lost, so the house is never left without a make-up air path. With a power close damper, the current sensor needs to be the normally closed type that opens its contacts when it detects the hood running.
Why this approach
A packaged make-up air damper only opens a passive inlet. Pairing the HAC with the furnace fan through the ADP turns make-up air into an active supply, similar to a dedicated exhaust fan switch in a new build. It also means the contractor is installing standard Hoyme parts with colour wiring diagrams in the box, and the branch is selling parts it already knows.
As always, the local building inspector has the final say on what is acceptable for a given installation, so we asked the contractor to confirm the arrangement locally.
Have a similar job?
Call free technical support at 1-800-661-7382 with the hood size, duct size and furnace type, and we will put together the part numbers with you. For US installations, see our guide to range hood make-up air under the IRC. For a related sequence, see proving a fresh air damper open before the fan starts.