Author Topic: Why is my laundry room fan constantly running (Read 8881 times)

MillCreek · « **on:** November 28, 2016, 08:23:19 AM »

The laundry room fan works on a timer switch and is used as a whole-house exhaust fan. I have it set to come on for certain intervals throughout the 24-hour day. Just recently, it is on all the time, regardless of if the timer switch is set for on, off or auto. I thought the switch was bad, so in preparation to replace it, just pulled it from the wall and disconnected all four spade terminals on the switch. The fan is still running, which perplexes me. I thought that disconnecting it from the switch would turn it off. Any ideas as to what the problem is and how to fix it?

bedlamite · « **Reply #1 on:** November 28, 2016, 08:24:57 AM »

detcord.

Hawkmoon · « **Reply #2 on:** November 28, 2016, 08:32:58 AM »

You need to trace the wiring from the "hot" side of the fan. The switch should be in the hot lead, and obviously it wasn't wired that way. It may be that the switch was installed on the ground side of the fan motor, which would be a violation of the electrical code. If that's the case, the fan has obviously found another ground path or it wouldn't run. The other possibility is that the timer you thought was for the fan ... isn't.

I also don't know why a switch for a 120-volt fan would have four terminals. It only needs two. Can you post a photo of the switch? And maybe one of the box from which you removed the switch, too, so we can see the wires.

freakazoid · « **Reply #3 on:** November 28, 2016, 09:10:44 AM »

K Frame · « **Reply #4 on:** November 28, 2016, 09:50:25 AM »

Is the switch a low voltage control or line voltage?

If low voltage, it could have failed and left the fan in the on state.

As for four terminals...

Could it be a three way switch, where one switch, if flipped, engages timer switch control, and if flipped the other way, manually overrides the timer?

K Frame · « **Reply #5 on:** November 28, 2016, 09:59:15 AM »

Regarding the number of terminals...

When I wired in a timer for my bath fan, it had 4 leads -- black, red, white, and green. I'm assuming that's what's being talked about here. (as opposed to 4 leads PLUS the ground)

This diagram shows the 4 leads and how they're wired...

Black on the switch goes to the black power leg in the box.

Red on the switch goes to the black load leg in the box (load leg = the fan)

White to white

Green to green

MillCreek · « **Reply #6 on:** November 28, 2016, 10:07:05 AM »

Picture one

MillCreek · « **Reply #7 on:** November 28, 2016, 10:07:32 AM »

Picture two

MillCreek · « **Reply #8 on:** November 28, 2016, 10:08:03 AM »

Picture three

K Frame · « **Reply #9 on:** November 28, 2016, 10:12:50 AM »

Looks like a standard switch for single pole line voltage.

So, you disconnected the switch COMPLETELY from the wall, as in there's NO connection between the black wires (and thus the fan should not be getting power at all)?

If that's the case...

Call an electrician.

MillCreek · « **Reply #10 on:** November 28, 2016, 10:25:14 AM »

The switch is completely disconnected from all power leads, and is hanging there by the zip tie bundling the wires together to the switch. The fan continues to run.

K Frame · « **Reply #11 on:** November 28, 2016, 10:37:45 AM »

Quote from: MillCreek on November 28, 2016, 10:25:14 AM

The switch is completely disconnected from all power leads, and is hanging there by the zip tie bundling the wires together to the switch. The fan continues to run.

Hum...

I think that's natures way of saying go find the breaker and pull the damned thing.

If the fan shuts off, then turn the breaker back on and see if the fan restarts.

If it doesn't, then you need to pull the breaker again and start doing some sleuthing with a multimeter and continuity tester.

What's extremely troubling is that the fan apparently found an alternate source of power, which could mean that something is really boned up in the wiring. Why a wiring issue like that wouldn't trip the breaker, I don't don't know.

If you don't have a multimeter and continuity tester, don't even try to investigate this yourself. If somehow there IS a second power lead to the fan, it could be coming from a different breaker...

Ben · « **Reply #12 on:** November 28, 2016, 10:46:58 AM »

Quote from: Mike Irwin on November 28, 2016, 10:37:45 AM

Hum...

I think that's natures way of saying go find the breaker and pull the damned thing.

If the fan shuts off, then turn the breaker back on and see if the fan restarts.

If it doesn't, then you need to pull the breaker again and start doing some sleuthing with a multimeter and continuity tester.

What's extremely troubling is that the fan apparently found an alternate source of power, which could mean that something is really boned up in the wiring. Why a wiring issue like that wouldn't trip the breaker, I don't don't know.

If you don't have a multimeter and continuity tester, don't even try to investigate this yourself. If somehow there IS a second power lead to the fan, it could be coming from a different breaker...

Millcreek, your house is still pretty new, right? Do you still have the home warranty on it? Depending on the deductible, I might first do what Mike said about hitting the breaker, but for further troubleshooting, I might at that point activate the warranty.

Actually if it was me with my minimal electrical knowledge, I would just call the electrician even without a warranty, especially if there's a chance that the original electrical contractor may have done something hinky. For peace of mind, the electrician can check more of your circuits to look for improper grounding, etc.

MillCreek · « **Reply #13 on:** November 28, 2016, 10:49:36 AM »

I went out to the breaker panel in the garage. When I flip the breaker for the garage lights, the lights and fan in the laundry room (which is adjacent to the garage) turn off. When I flipped the breaker back on, the lights and fan came back on.

K Frame · « **Reply #14 on:** November 28, 2016, 10:55:28 AM »

Quote from: MillCreek on November 28, 2016, 10:49:36 AM

I went out to the breaker panel in the garage. When I flip the breaker for the garage lights, the lights and fan in the laundry room (which is adjacent to the garage) turn off. When I flipped the breaker back on, the lights and fan came back on.

Well, now we're back to my theory that the fan is somehow pulling power from another sources on the same breaker...

But, I simply can't see how that wouldn't cause a short circuit and pop the breaker.

If, as Brad says, you do have a home warranty... time to turn the breaker OFF, leave it off, and activate the warranty.

In other word, it's time to start acting like the APS Risk Manager your ID block claims that you are.

Ben · « **Reply #15 on:** November 28, 2016, 10:59:29 AM »

Quote from: Mike Irwin on November 28, 2016, 10:55:28 AM

If, as Brad says,

How dare you, sir. How. Dare. You.

K Frame · « **Reply #16 on:** November 28, 2016, 11:06:43 AM »

Quote from: Ben on November 28, 2016, 10:59:29 AM

How dare you, sir. How. Dare. You.

At least I didn't call you Jamis.

bedlamite · « **Reply #17 on:** November 28, 2016, 11:09:00 AM »

Now that we know the fan is on the garage circuit, Is there anything that doesn't work now that the switch is disconnected?

Triphammer · « **Reply #18 on:** November 28, 2016, 11:34:54 AM »

What's the possibility of a second, parallel switch that overrides the timer in cases of heat or humidity?

Brad Johnson · « **Reply #19 on:** November 28, 2016, 11:53:33 AM »

Possibilities include, but are not limited to...

A) Thermostatically controlled parallel circuit that has failed in the on position.

B) Switch is there only to activate a contactor/relay, and the contactor has failed in the on position.

C) There is a wiring fubar that is letting the fan backfeed from a second circuit.

D) Your home was built over a cemetery and the developer only moved the headstones.

Quote from: Ben on November 28, 2016, 10:59:29 AM

How dare you, sir. How. Dare. You.

Bwahahahahahahahahaha!!!!!!!!!!!!!!!!!!!!!

Brad

Hawkmoon · « **Reply #20 on:** November 28, 2016, 01:24:26 PM »

Quote from: Mike Irwin on November 28, 2016, 10:12:50 AM

Looks like a standard switch for single pole line voltage.

Looks to me like a switch for 240 volts, and the diagram on the back says there should be five terminals, not four.

Hawkmoon · « **Reply #21 on:** November 28, 2016, 01:26:23 PM »

Quote from: MillCreek on November 28, 2016, 10:07:32 AM

Picture two

Call an electrician. I'm pretty certain that box is too small for the number of conductors and wire nuts inside, and that's an accident waiting to happen.

K Frame · « **Reply #22 on:** November 28, 2016, 02:01:28 PM »

Judging by the print on the back it appears that it can be used in either 125 or 250 volt applications.

My guess is that is the 5th terminal, for the extra hot leg.

Sent from my SCH-I545 using Tapatalk

Triphammer · « **Reply #23 on:** November 28, 2016, 02:24:35 PM »

There's 2 terminals for the timer motor which is 110 only the switch is single pole one normally open one normally closed and a common. which can be used in either a 110 or 220 circuit.
I'm still thinking some kind of parallel switch circuit. Maybe even an unidentified (what looks like) light switch to override the timer w/o have to mess w/ the timer every time.

MillCreek · « **Reply #24 on:** November 28, 2016, 02:44:05 PM »

Quote from: Triphammer on November 28, 2016, 02:24:35 PM

There's 2 terminals for the timer motor which is 110 only the switch is single pole one normally open one normally closed and a common. which can be used in either a 110 or 220 circuit.
I'm still thinking some kind of parallel switch circuit. Maybe even an unidentified (what looks like) light switch to override the timer w/o have to mess w/ the timer every time.

Found it. An auxiliary light switch that over-rides the timer switch. My wife turned it on; I did not even know the switch was there.

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Author Topic: Why is my laundry room fan constantly running (Read 8881 times)