Replies

1. 
   catmandeux | Nov 16, 2015 05:48pm | #1

   The 2 switches are wired in series. Power ( black wire ) goes to the emergency switch.  Return from this switch then goes to the master switch.  Make sure the white wire is marked as " hot" with black permanet marker or tape. 

   Your electrician will now how to do this.  If you are doing it yourself, it should be inspected.

1. 
   me@memo2023 | Nov 17, 2015 12:55pm | #3

   Update Graphic

   Thank you! I think this is what you mean (see UPDATED graphic). It will be inspected along with other plubming issues I just want to get installed before I fire up the furnace for the season. My electrician is out of town it turns out. Just to be clear, I have one switch immediately next to the furnace, this is a second switch at the top of the basement stairs.

   
1. 
   DanH | Nov 17, 2015 08:14pm | #5

   Can't make heads or tails of that diagram, but it looks wrong, what I can make out.

2. 
   catmandeux | Nov 17, 2015 08:40pm | #6

   Switches have to be in series, so both must be on to energize the furnace.  Either one off breaks the circuit.

   Question:  Emergency switches are not normally used with gas furnaces.  Required for oil burners.  Is this a local code issue?

   
1. 
   me@memo2023 | Nov 18, 2015 09:06am | #8

   Emergency Swtiches Are Requried

   Code requires two switches (in a series) for both gas and oil furnaces. My HVAC guy is coming next week but my electrician is MIA. So, I am stuck. Googling two spst in a series (or anything to that affect) gets poor relsults. I'll just wait.

   Thanks for the time.

2. 
   calvin | Nov 16, 2015 06:30pm | #2

   gs

   no kidding, an "emergency" switch for the furnace?

   Man, glad I'm trying my damndest to retire.

3. 
   me@memo2023 | Nov 17, 2015 12:58pm | #4

   Removed by Original Poster - I meant to reply.

4. 
   DanH | Nov 17, 2015 08:56pm | #7

   Note that what you need is similar to a "switch leg" for lighting. 

   View Image

   The difference is that instead of the lamp socket you have the existing furnace power switch.

   Note that the incoming black goes only to the emergency switch (by means of the white wire painted black).  The black wire coming from the emergency switch then goes to the place where the original black wire once connected.  No (unpainted) white wire goes to the emergency switch.  And, of course, ground wires (not shown above) are all interconnected.

1. 
   me@memo2023 | Nov 18, 2015 09:16am | #9

   THIS IS IT!

   This is what I am looking for. I think I get it. THANK YOU!!!!!

5. 
   PTGoldstein | Feb 24, 2016 11:21pm | #10

   I am too completely satisfied with the answer by DanH.

1. 
   calvin | Feb 25, 2016 07:08am | #11

   PT

   I'm wondering why your username isn't anywhere close to your email address?

6. 
   Here_to_Help_3732 | Mar 30, 2022 12:29pm | #12

   I am dropping our website here https://www.mistersparky-houston.com/ we have a lot of resources for free that can help inform both old and new electricians or just those who are looking to learn more about the industry! Hope this helps!