The Alberta Building Code requires the principal exhaust fan to be interlocked with the furnace fan. An average size home usually has 2 bathroom fans upstairs, 1 downstairs. How do I determine what is the principal exhaust fan? Do I have to interlock all the bathroom fans with the furnace. On some newer homes I've seen there is a switch in the hallway, that somehow is wired in with the fan and furnace. What is the correct way to wire the fan and furnace in a new home. Thanks for any replies.

This is about all i can help you with http://www.bcelectrician.com/furnace_fan_timer.html

Doug, do I understand this right? When the "principal exhaust fan" is switched on, the furnace fan must also come on. It is assumed that the furnace also supplies make up air.

LarryC

The Alberta Building Code does not say which exhaust fan must be used as the principle exhaust fan (it can be any exhaust fan in the home except the range hood fan). However the fan must have sufficient capacity to provide 50% of the total ventilation requirements of the home (ABC 9.32.3.4.(1)). And the switch must be centrally located (ABC 9.32.3.4(4)). Also two or more exhaust fans may be interlocked together so that they function simultaneously as the principal exhaust fan (ABC 9.32.3.4.(3)).

[This message has been edited by crash (edited 06-27-2006).]

[This message has been edited by crash (edited 06-27-2006).]