3-Way Switches to Oil Furnace
#1
06-07-13, 10:12 AM
3-Way Switches to Oil Furnace
Hi all, I frequently visit the plumbing forum but this is an electrical question at the oil furnace.
Last Spring when I fired up my oil furnace (It was dormant through the winter due to using an outdoor wood fired boiler to provide the necessary hot water for circulation and domestic use) the oil furnace smoked up badly. In order for me to turn it off I had to enter the basement through the thick smoke to get to the switch. I really didn't like that. I was wondering if the switch box can be extended to a location at the top of the stairs leading to the basement? My best guess is a couple of 3-way switches and 12/3 with ground (Like was used when the 3-way circuit was installed to control my ceiling lights in my living room). If this is not how it's done, please set me straight. Roger
Last Spring when I fired up my oil furnace (It was dormant through the winter due to using an outdoor wood fired boiler to provide the necessary hot water for circulation and domestic use) the oil furnace smoked up badly. In order for me to turn it off I had to enter the basement through the thick smoke to get to the switch. I really didn't like that. I was wondering if the switch box can be extended to a location at the top of the stairs leading to the basement? My best guess is a couple of 3-way switches and 12/3 with ground (Like was used when the 3-way circuit was installed to control my ceiling lights in my living room). If this is not how it's done, please set me straight. Roger
#2
06-07-13, 12:17 PM
If this is a service disconnect it might be safer to use two SPST switches (regular on/off switches) in searies. With a three way switch a service man might think he was safe by turning off the switch nearest the furnace only to have someone turn it back on from the remote switch while he was working on it. With two switches in series either switch can keep the furnace off.
#3
06-07-13, 12:43 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
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Exactly my thoughts, Ray.
Roger, run a new two-conductor cable (with ground) from the top of the stairs to the local disconnect switch. Re-identify the white wire in this new cable on each end changing the color to black. Wire the new switch to the insulated conductors at the top of the stairs. Remove ONE of the wires from the existing switch and connect it to one of the wires of the new cable with a wire nut. Connect the remaining wire from the new cable to the local disconnect switch where you removed the wire you connected to the new cable.
This arrangement is safe. Both switches will need to be in the ON position for the burner to operate and neither switch can be bypassed by operating the other switch. You should also get one of the red switch plates for the upstairs switch that has the legend Oil Burner Emergency Switch stenciled on it.
Roger, run a new two-conductor cable (with ground) from the top of the stairs to the local disconnect switch. Re-identify the white wire in this new cable on each end changing the color to black. Wire the new switch to the insulated conductors at the top of the stairs. Remove ONE of the wires from the existing switch and connect it to one of the wires of the new cable with a wire nut. Connect the remaining wire from the new cable to the local disconnect switch where you removed the wire you connected to the new cable.
This arrangement is safe. Both switches will need to be in the ON position for the burner to operate and neither switch can be bypassed by operating the other switch. You should also get one of the red switch plates for the upstairs switch that has the legend Oil Burner Emergency Switch stenciled on it.
#4
06-07-13, 04:27 PM
Fund, Ray; Thanks so much for correcting me. The last thing I would want to do is inadvertently injure or worse yet, kill someone due to doing something wrong. 
I'll definitely wire it the way Fund described. Thanks again. Roger
I'll definitely wire it the way Fund described. Thanks again. Roger
