Description
CSA-certified motorized fresh air damper that installs at the exterior wall penetration: hood and damper combined in one unit. No separate exterior hood required. One wall opening, one CSA-certified assembly, one control point. 24 Vac spring return, 4"–9", PO or PC action.
✓ Seals at the building wall: no passive hood opening exposed to outdoor air between ventilation cycles; no cold air column sitting in the duct run
✓ One unit replaces two: eliminates the separate exterior hood and inline damper that a standard HAC + OOH installation requires
✓ Same stall-protected Hoyme spring motor drive: nylon bearings, engineered for freeze-thaw cycling and outdoor temperature exposure
✓ Canada/USA CSA certified
✓ PO or PC action, end switch and relay available: all factory-installed; confirm the action at order, although it can be converted in the field using the Hoyme conversion procedure
✓ MAC-L available: factory-insulated body for cold climate installs where condensation on the damper body is a concern; specify at order
Confirm PO vs. PC before ordering. The action is set at the factory. It can be converted in the field using the Hoyme conversion procedure, but ordering the right action saves a service call. Power Open (PO) is correct for the vast majority of fresh air intake and make-up air applications: the duct seals when the system is off. Power Close (PC) is used only when fail-open on power loss is required by the system design.
Choose MAC when…
✓Damper at the exterior wall penetration is preferred
✓Single unit covers both termination and control
✓Tightest possible exterior air seal is a priority
✓Retrofit where adding a second interior unit is impractical
Choose HAC + OOH when…
→Damper needs to be in the duct run, accessible indoors
→Separate exterior hood already part of the design
→Sizes above 9" required
→Interior control point preferred for new construction
Key Advantage
Seals at the wall, no open hood between cycles
Sizes
4"–9"
Voltage
24 Vac
Action
PO or PC
Certification
Canada/USA CSA
Insulated version
MAC-L: specify at order
Need an ADP relay adaptor? To interlock the MAC with the furnace fan, use the ADP-0241-05A (24 Vac ventilation switch) or ADP-1101-05A (120 Vac exhaust fan switch). Both open the damper and start the furnace fan together, with no end switch required. Where an exhaust fan must wait until the damper proves open, use a TPX proving adaptor and order the SPO or SPC variant.
2-year electrical · 10-year mechanical warranty
Made in Canada · 40+ years field-proven in Canadian climates
Product image is representative only. Actual product may differ in appearance depending on size, configuration, and options selected at order.
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