exhaust vent wiring

[dmastin]

New bathroom has vanity light and exhaust vent/light/heater combo unit.
There are three rocker switches in this order.
a) One switch for vanity light. Two black wires.
b) One switch for exhaust vent and light. They turn on together. Two black wires and one red.
c) One switch heater. Two black wires.
I would very much like to convert “b” to a stacker switch such that I can turn on the vent light without turning on the vent.
Does it sound like I will be able to do so with the wiring I have?

 

[Ashful]

A few pictures are worth a few thousand words. It's not clear to me if the wires you're describing are your house wiring, going to standard screw terminal switches, or the wires on molded wiring switches mounted in the vent unit itself. In theory, to operate vent, light, and heater independently, you would need four wires (typically one white with three black or colored), plus ground (green or green/yellow).

 

[EatenByLimestone]

A few pictures are worth a few thousand words. It's not clear to me if the wires you're describing are your house wiring, going to standard screw terminal switches, or the wires on molded wiring switches mounted in the vent unit itself. In theory, to operate vent, light, and heater independently, you would need four wires (typically one white with three black or colored), plus ground (green or green/yellow).

Check each wire to find your hot(s) coming into the box. I've seen multiple circuits coming in before. Not all have been wired correctly.

 

[greg13]

Use a 2 gang box, a stack switch for light & Heater and a timer in the other side for the vent.

 

[fbelec]

definitely if you don't have a two gang box you will need one. and if the job was done right in the beginning there should be a separate circuit for the heater. 12 ga. 20 amp circuit. the heater should be a 1500 watt heater and 1400 watts are legal limit for a 15 amp circuit. timers are a great idea for the vent. everybody forgets and leaves them running for hours, if going with a timer and separate lighting switches you'll need a three gang box