a) Gas Burning Appliances

7.1 General ...

...7.1.3 Interference with the air supply for an appliance is prohibited.

7.5 Air Supply Damper, Louvres and Grilles ...

...7.5.3 Neither a manually-operated damper nor manually-adjustable louvres shall be used.

7.5.4 An automatically-operated damper or automatically-adjustable louver shall be interlocked so that the main burner cannot operate, unless either the damper or louver is in the fully open position.

7.5.5 An automatic combustion air damper installed in the air supply within a dwelling unit shall be certified.

b) Oil Burning Appliances: CAN/CSA-B139-M91

4.4.1.5

When a damper is provided in any opening intended to admit combustion air into the room within which the appliance is installed, the damper shall be interlocked to prevent any burner from starting before the damper is fully open.

*Model National Energy Code of Canada for Houses - 5.2.3. Air Intake and Outlet Dampers

5.2.3.1. Required Dampers
1) Except as provided in Sentence (3) and (4), every duct or opening intended to discharge air to the outdoors shall be equipped with a motorized damper or gravity or spring-operated backdraft damper.
2) Except as provided in Sentence (3) and (4) and except in regions that have fewer that 3500 degree-days (C) as listed in Appendix C of the National Building Code of Canada, every outside air intake duct or air intake opening shall be equipped with a motorized damper.
3) Where dampers are not permitted by other regulations, air intakes and outlets need not comply with Sentences (1) and (2).
4) Air intakes and outlets serving systems required to operate continuously need not comply with Sentence (1) and (2).

*Model National Energy Code of Canada For Houses 1997 - Part 5.2.3.1 Reprinted with permission From National Research Council, Canada.

HOYME Combustion Air DAMPERS and ACCESSORIES are Certified as required by the the CANADA B149.1-M95 Gas Code. The Model National Energy Code for Canada asks for Motorized Dampers on all passive fresh air inlets, including fresh air for Ventilation and Combustion air. Modern Building Ventilation Codes also require EXHAUST AIR to be controlled by BACKDRAFT DAMPERS and/or FANS.

Control COMBUSTION MAKE-UP-AIR with series HOM fresh air damper interlocked to the Safety Control of a furnace or boiler: THESE DAMPERS ARE CERTIFIED AS REQUIRED BY THE NATIONAL GAS CODE and are also certified for OIL. Use Damper Series 'HOM - SF1' for one appliance and 'HOM - SF2' for two appliances. (See special pricing for Damper Series 'HOM', if bought in kit form. See Interlocking Adapters for Residential and Commercial use.)

Control COMBUSTION AIR for OIL with Series MAC, HAC or MOH - all equipped with optional end switches to be interlocked with the safety control system of the oil burner.

Control VENTILATION REPLACEMENT AIR by INTERCONNECTING a Fresh-air-intake Damper, a Relay Control Center and a Principal Exhaust Fan: HOYME RELAY ADAPTERS are special so that the manual FAN SWITCH AND/OR centrally located VENTILATION SWITCH turns on the EXHAUST FAN, FURNACE FAN (if not running) and opens FRESH AIR INTAKE DAMPER simultaneously. Use damper SERIES 'HAC' coupled with a relay adapter ADP-1102-TXX. (This special relay adapter may be ordered with a TIMER (if required) TMADP-1102-TXX). Dampers and Relay Adapters are often ordered as a kit. (SEE DAMPER SERIES 'HAC', 'HAC KIT' AND ALSO SECTION ON VARIOUS ADAPTERS.)
BACKDRAFT DAMPERS without motors: Regular round (BDD); Spring loaded Backdraft Hoods (BDH).

PASSIVE FRESH AIR INLET DUCTS are sometimes plugged and therefore become unsafe. Alternatively, Motorized Dampers are safe as there is no need to plug the duct. OUR MOTORIZED DAMPERS provide added comfort, are safe and prove to save energy.