Fresh Air Dampers

Motorized dampers for fresh air intake, make-up air and HRV/ERV duct control. A fresh air damper keeps the outdoor air duct sealed between ventilation cycles and opens when ventilation is called, so the building is not leaking cold air every hour the system is off.

Choosing a fresh air damper

• Inline, 2 to 9 in.: the HAC inline damper, 24 Vac, CSA certified. Use the HAC-12 where only 120 Vac is available at the damper.
• Condensation risk: insulated -L models for dampers in unconditioned space. See cold climate products.
• Tight spaces: the HAC-E motorized elbow damper.
• At the wall: the MAC terminating-end damper and MOH motorized hood combine the damper and the exterior termination.
• Larger ducts: the HAC-50/51 quarter-turn and HAC-40 Belimo models. See large diameter dampers.

Power open is the usual choice

For fresh air, make-up air and HRV/ERV ducts, power open (PO) is correct on the vast majority of jobs: the damper opens on a ventilation call and springs closed when the call ends. Read the power open vs power close guide before ordering.

Interlocking with the furnace fan or an exhaust fan

The ADP-0241-05A opens the damper and starts the furnace fan together from a 24 Vac ventilation switch, and the ADP-1101-05A does the same from a 120 Vac exhaust fan switch. Neither needs an end switch on the damper. Where the exhaust fan must wait until the damper proves open, use a TPX proving adaptor with an end switch damper (SPO or SPC). See the ADP selection guide, and for Ontario work, the OBC 2024 make-up air guide.

Supplying make-up air for a range hood, exhaust fan or gas dryer? See make-up air dampers for the damper and interlock combinations.

Questions on sizing or wiring? Call technical support at 1-800-661-7382. Sold through HVAC wholesalers across Canada, or order direct here.