Strange switch behaviour cannot be explained ... by me.


  #1  
Old 11-26-16, 10:51 AM
L
Member
Thread Starter
Join Date: Nov 2016
Location: Canada
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
Strange switch behaviour cannot be explained ... by me.

An upstairs bathroom has a downstairs switch for the fan (builder installed) - it feeds up to the bathroom where there are 3 distinct switches: single pot light switch, vanity light switch and bathroom fan switch. Obviously this fan switch is wired to the downstairs switch too. The existing on off fan switch has 3 wires (not counting the ground) leading into it:
red (feeds to the downstairs switch) hot black (which is jumped to ALL THREE outlets - builder electricians) and a white neutral ....

This switch works but we prefer to install a humidity triggered switch to avoid having steam build up in the bathroom. The humidity switch has three wires (not counting the ground): red, black and white.

When I connect these wires to the appropriate colors, the switch is powered (led lights up) but the fan won't turn on (even if you breathe into the sensor, or bypass the sensor with the manufacturer instructions). I thought it was the switch so I purchased a different brand and same result.

Same three wires work with the regular switch, but not with the special switch.
Oh, it looks like they only used 14-3 from the downstairs switch to the bathroom, and 14-2 from the bathroom to the fan motor.

Does this make sense? Thought I would check in before calling the electrician.... Thanks!
Lance
 
  #2  
Old 11-26-16, 11:25 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,939
Received 3,951 Upvotes on 3,544 Posts
Welcome to the forums.

Does this make sense?
No. Why does a switch downstairs control a fan in the upstairs bathroom ?
OR.... is there a common fan that vents the upstairs and downstairs bathroom ?

The wiring makes sense.

I've found that a mechanical switch or a timer is more effective than a humidistat.
 
  #3  
Old 11-26-16, 01:04 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
The existing on off fan switch has 3 wires (not counting the ground) leading into it:
red (feeds to the downstairs switch) hot black (which is jumped to ALL THREE outlets - builder electricians) and a white neutral ....
It sounds to me like you have a 3-way switch. There is probably only one fan and the builders intended it to be switched up or downstairs.
The white attached to the 3w wouldn't be a neutral, it's most likely a traveler.
You probably have a neutral bundle in the box since you have 2 other switches there, but you might need some other type of switch.
 
  #4  
Old 11-26-16, 01:17 PM
L
Member
Thread Starter
Join Date: Nov 2016
Location: Canada
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
Yes, I didn't mention but there is a substantial twist of common (white) wires EXCLUDING the one that is in the fan feed ... I have been told that building code (for Ontario anyways?) stipulates the need for a downstairs switch during home construction (to make sure the fan is helping expel the humidity from all-season construction). So this switch wouldn't work with a 3 way switch or I need to remove the downstairs switch ..... ?
Thanks!
 
  #5  
Old 11-26-16, 01:44 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
I wouldn't remove the downstairs switch.
Your new switch isn't a 3w, it requires a neutral which is the white wire.

You need some type of 3w timer to replace the switch.
 
  #6  
Old 11-26-16, 03:15 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,939
Received 3,951 Upvotes on 3,544 Posts
You don't have to remove anything. You have a three wire system.... NOT a three way system.

The white is strictly neutral. Black is hot and red is the fan load.
Any short from red to black will make the fan run.

I have been told that building code (for Ontario anyways?) stipulates the need for a downstairs switch during home construction (to make sure the fan is helping expel the humidity from all-season construction)
That is pretty vague.
That means if the switch is off downstairs that humidity is not being expelled ?
What good is that. Plus... if either switch is on.... the fan runs.
 
  #7  
Old 11-26-16, 03:44 PM
L
Member
Thread Starter
Join Date: Nov 2016
Location: Canada
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
Then why does the old switch (with the same connected wires - black white and red) operate the fan? Is there a schematic difference with humidity or motion, etc. type switches?
 
  #8  
Old 11-26-16, 03:50 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,939
Received 3,951 Upvotes on 3,544 Posts
If the old switch needed white then maybe it was some type of automatic switch.
You could post a picture of the old switch and we'd know for sure.
http://www.doityourself.com/forum/el...-pictures.html
 
  #9  
Old 11-26-16, 03:57 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
The humidity switch has three wires (not counting the ground): red, black and white.
I don't think I'm confused. The humidity switch has red, black and white. Your old switch had the same color wires attached, but the white was not neutral.

If the old switch has 2 brass colored terminals and one dark or marked terminal, it's a 3w.
 
  #10  
Old 11-26-16, 04:26 PM
L
Member
Thread Starter
Join Date: Nov 2016
Location: Canada
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
Old Switch:

Name:  image1.jpg
Views: 633
Size:  29.9 KB

Name:  image2.jpg
Views: 691
Size:  30.8 KB

Humidity Switch:

Name:  image3.jpg
Views: 622
Size:  32.3 KB

Name:  image4.jpg
Views: 597
Size:  29.1 KB

Name:  image5.jpg
Views: 582
Size:  30.6 KB
 
  #11  
Old 11-26-16, 07:16 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,939
Received 3,951 Upvotes on 3,544 Posts
Your old switch is a three way switch.
Your new humidity control is not.

In order to use the humidity control there will need to be a few wiring changes made at the upstairs switch location. After installing the humidity switch.... the downstairs switch will no longer work.
 
  #12  
Old 11-26-16, 08:31 PM
L
Member
Thread Starter
Join Date: Nov 2016
Location: Canada
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
I see. The feed from the downstairs is 14-3 wire, but the feed to the fan (in the bathroom box) is 14-2. SO, what would the Red load wire (on the new switch) be connected to? Do I have to run a 3rd wire up to the fan motor? Or can I just attach the red switch wire to the black wire (14-2 run to the fan motor), attach the hot black wire to the proper switch connector and the neutral of the fan motor feed to the white connector on the switch?

Thanks!
Lance
 
  #13  
Old 11-27-16, 02:38 AM
E
Member
Join Date: Nov 2016
Location: USA
Posts: 135
Upvotes: 0
Received 3 Upvotes on 3 Posts
In the three gang switch.
1. Find the 14/3 going downstairs,
2. Follow the black wire from the 14/3. It should be connected to a black wire (14/2) inside the three gang box. Identify this black wire (14/2) with a piece of tape.
3. Disconnect all three wires in the 14/3, they will no longer be used.
4. The downstairs switch will be dead. The 14/3 has black, red, white and ground. The ground can remain connected. This 14/3 could possibly be used in the future, but for this discussion, just leave it dead.
5. Inside the three gang box, find the white wires (neutrals) which are all tied together.
6. Connect a new white wire to feed your new humidity switch.
7. Connect the new humidity switch, Black (Hot) the one feeding all three switches goes to the black screw on the humidity switch.
8. White goes to the silver screw
9. Black, the one you identified with tape, goes to red screw.
10. Buy a white blank plate for the downstairs switch.
 
  #14  
Old 11-27-16, 06:17 AM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
Pete suggested a timer in post 2, I would do the same. There's no need to remove the downstairs switch or change any wiring.
If you buy a battery operated 3-way timer, it is a simple matter of connecting the same three wires that were attached to the old switch.

If you don't want a battery, you can get one with a neutral and connect that into the existing bundle.
The battery type allows you to program the switch before installing and doesn't require a neutral.
 
  #15  
Old 11-28-16, 06:56 PM
L
Member
Thread Starter
Join Date: Nov 2016
Location: Canada
Posts: 6
Upvotes: 0
Received 0 Upvotes on 0 Posts
So it also turns out the supplied switch is faulty, so I'll have to deal with that separately. I used the spare one and followed the instructions here. As we don't need that switch downstairs, we'll 'blank' it. This is all because of a teenager that refuses to turn the fan on when showering .... teenagers .... this switch works perfectly because even if he manually turns it off, increasing humidity will turn it on (while he's in the shower).

Thanks so much! You all helped a great deal and I appreciate your patience!

Lance
 
  #16  
Old 11-28-16, 07:02 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 4,807
Upvotes: 0
Received 0 Upvotes on 0 Posts
You are pretty good at electric to be able to bypass the switch like you did.
Good job
 
  #17  
Old 11-29-16, 05:37 AM
E
Member
Join Date: Nov 2016
Location: USA
Posts: 135
Upvotes: 0
Received 3 Upvotes on 3 Posts
Glad it works. Teenagers!
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: