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[dahur]

Four months ago I installed a magnetic switch on my front door. I wired it to a Powerflash, and put in a BVC audible response to have "Callie",  tell when the front door is open/closed. 
It worked perfect until last week. I searched and found some posts on here from someone who had trouble with their Powerflash's, so I ordered another one. Nope, same thing. To make a long story short, I have steel front doors. Seems the magnet, for whatever reason decided to act up with the door. Why it took 4 months beats me. If I take the magnet off the door, and hold in my hand, and move it, the Powerflash functions perfectly. Attach it to the door, and no signal sent.
I was wondering if anyone has a possible fix for this, or a know of a different/stronger switch I could try.



 

[Alan V]

Four months ago I installed a magnetic switch on my front door. I wired it to a Powerflash, and put in a BVC audible response to have "Callie",  tell when the front door is open/closed. 
It worked perfect until last week. I searched and found some posts on here from someone who had trouble with their Powerflash's, so I ordered another one. Nope, same thing. To make a long story short, I have metal front doors. Seems the magnet, for whatever reason decided to act up with the door. Why it took 4 months beats me. If I take the magnet off the door, and hold in my hand, and move it, the Powerflash functions perfectly. Attach it to the door, and no signal sent.
I was wondering if anyone has a possible fix for this, or a know of a different/stronger switch I could try.

The metal door is shunting the magnetic field.  Try putting a non-ferrous spacer between the door and the magnet.  Make sure that the reed switch is still aligned with the magnet after the spacer is installed.  You may have to play around with different thicknesses of spacers.   

[Tuicemen]

I seen a bit of info On the discovery channel about metal objects getting magnetized just by there orientation!
This can be observed with the use of a compass! North side of the object becomes magnetic north, moving a compass from the south side to the north side will spin the needle!
If  Alan V suggestion doesn't work and the magnetic switch is at the side of the door try placing it at the top! Also don't use ferrous screws to fasten!
I haven't experience problems with my steel doors and the sensors but they also have a steel jam in which the switches are mounted! 

[dahur]

Thanks for the info guys. A helpful to each of you.


The only thing I can come up with is the repeated opening and closing of the door over four months created, or strengthened a magnetic field on my door.  Then one day, it just interfered with the reed switch enough to make it non-functional.  The reed switch I have is rated at 3/4 gap, and I remember I had to almost have them touching to get it to work. So something was already there. Now, if I have the switch closer than 2 inches from the door, it won't work.  I can jury-rig something to jut it out from the door, but I really don't like the look of too much visible stuff. 

[PajamaGuy]

I assume you tried new batteries.  Have you mounted the contacts using wood or plastic so that they're raised up from the metal surface?

[dahur]

I assume you tried new batteries.  Have you mounted the contacts using wood or plastic so that they're raised up from the metal surface?

There are no batteries involved. It's a dry contact switch feeding into the Powerflash.  If the switch gets closer than about 2 inches to my steel door, it won't function correctly. This is with me holding it. I originally had two metal screws holding the magnet on the door.  When it started to malfunction, and after I found it wasn't the Powerflash, I built up layers of mastic tape to see how far away from the door it would operate. I couldn't make it thick enough to get it to work. So while holding it, I gauge the distance at about 2 inches.  It's really strange.  The magnets haven't gotten weaker, because away from the door, they operate within the 3/4 gap they're rated at. The door's magnetic field has gotten stronger I guess.

[Alan V]

I assume you tried new batteries.  Have you mounted the contacts using wood or plastic so that they're raised up from the metal surface?

There are no batteries involved. It's a dry contact switch feeding into the Powerflash.  If the switch gets closer than about 2 inches to my steel door, it won't function correctly. This is with me holding it. I originally had two metal screws holding the magnet on the door.  When it started to malfunction, and after I found it wasn't the Powerflash, I built up layers of mastic tape to see how far away from the door it would operate. I couldn't make it thick enough to get it to work. So while holding it, I gauge the distance at about 2 inches.  It's really strange.  The magnets haven't gotten weaker, because away from the door, they operate within the 3/4 gap they're rated at. The door's magnetic field has gotten stronger I guess.

It's possible that the magnet itself has magnetized the door over time (at least in the area that it was placed).  As a test, try placing the magnet in a spot far away from the original mounting location.  I don't think that the door's orientation to the Earth's magnetic field has anything to do with your problem.  The Earth's magnetic field is about 0.5 Gauss (much too weak to cause a problem here).

[dave w]

dahur
Pretty weird! I think we all would be interested in hearing if you find an explanation.

[dahur]

It's possible that the magnet itself has magnetized the door over time (at least in the area that it was placed).  As a test, try placing the magnet in a spot far away from the original mounting location.  I don't think that the door's orientation to the Earth's magnetic field has anything to do with your problem.  The Earth's magnetic field is about 0.5 Gauss (much too weak to cause a problem here).

Per your suggestion, I moved the switch along the top of the door, (taping the switch to hold it in place), and anywhere near the door, it wouldn't operate the Powerflash.

[Alan V]

It's possible that the magnet itself has magnetized the door over time (at least in the area that it was placed).  As a test, try placing the magnet in a spot far away from the original mounting location.  I don't think that the door's orientation to the Earth's magnetic field has anything to do with your problem.  The Earth's magnetic field is about 0.5 Gauss (much too weak to cause a problem here).

Per your suggestion, I moved the switch along the top of the door, (taping the switch to hold it in place), and anywhere near the door, it wouldn't operate the Powerflash.

At this point, I would replace the magnet with a more powerful one.  Try a rare earth magnet (Neodymium Iron Boron) and use a non=ferrous spacer.  That's easier to replace than the reed switch, which needs to be more sensitive for your application.

[JimC]

dahur,

It could just be that the reed switch has built up oxidation. This is a common problem when these devices are use in dry applications ( little to no current ) When you remove the magnet form the door and move it toward the reed switch it may be working because you are getting it just a little clsoer to the switch and the magnet can exert a little more force on the switch.

You can check this by connecting an Ohm meter across the reed switch with nothing else connected. Open and close the door and watch the meter. If it is indicating a change in resistance but the resistance reads high the problem I described above could be your problem.

One possible solution is to run some current through the switch. This will sometimes burn off the oxidation. This can be done in several ways. The simplest is to take a 1.5 volt battery and connect it to the switch through a resistor. Bringing the magnet close to the switch with the battery connected will pass current through the switch. This may be enough to cause it to start working again. Caution should be observed as drawing too much current through the switch will pit the contacts and have the opposite effect.

I have used this method  with my rain gauge which uses a reed switch and  magnet and it has worked for me.

[dahur]

dahur,
) When you remove the magnet form the door and move it toward the reed switch it may be working because you are getting it just a little clsoer to the switch and the magnet can exert a little more force on the switch.

When I did the install last January, I had to install the switch almost touching the magnet, before it would work. I wondered about that then.  Away from the door, I can operate it at the 3/4 gap.

I also have two other dry contact switches I installed at the same time as this one. One on the wooden door from the house to the garage, and one on the garage door(aluminum). Both are working perfectly. 

This is the one that was on my front steel door. I have removed it, and am searching for a stronger version.

Thanks for the suggestion. I'll keep your option open, in case a stronger magnet won't work.

[Alan V]

dahur,

It could just be that the reed switch has built up oxidation. This is a common problem when these devices are use in dry applications ( little to no current ) When you remove the magnet form the door and move it toward the reed switch it may be working because you are getting it just a little clsoer to the switch and the magnet can exert a little more force on the switch.

You can check this by connecting an Ohm meter across the reed switch with nothing else connected. Open and close the door and watch the meter. If it is indicating a change in resistance but the resistance reads high the problem I described above could be your problem.

One possible solution is to run some current through the switch. This will sometimes burn off the oxidation. This can be done in several ways. The simplest is to take a 1.5 volt battery and connect it to the switch through a resistor. Bringing the magnet close to the switch with the battery connected will pass current through the switch. This may be enough to cause it to start working again. Caution should be observed as drawing too much current through the switch will pit the contacts and have the opposite effect.

I have used this method  with my rain gauge which uses a reed switch and  magnet and it has worked for me.

Reed switches are encased in hermetically sealed glass with inert gas inside.  Oxidation should not occur.  However, some reed switches are poorly made and the glass-to-metal seal is not very good.  If there is a leak, then oxidation can occur.  If you have to pass high current through the contacts in order to make the reed switch fuction, then I would replace the reed switch.

[Boiler]

When I did the install last January, I had to install the switch almost touching the magnet, before it would work. I wondered about that then.  Away from the door, I can operate it at the 3/4 gap.

I also have two other dry contact switches I installed at the same time as this one. One on the wooden door from the house to the garage, and one on the garage door(aluminum). Both are working perfectly. 

This is the one that was on my front steel door. I have removed it, and am searching for a stronger version.

Thanks for the suggestion. I'll keep your option open, in case a stronger magnet won't work.

Dahur,
Since your switch still functions when away from the door, I'd stick with Alan's fist instinct that your door is acting as a shunt to the magnetic field.

Over the period of the last four months with this shunt in place (your door) combined with shock (closing the door) the magnet may have weakened to the point where it can no longer activate the reed switch.

Try swapping magnets with one from your wooden door.  If this works it's simply a charge level.  In that case, use a thicker spacer between the magnet and the door to reduce the shunt.

Boiler

[dahur]

Try swapping magnets with one from your wooden door.  If this works it's simply a charge level.  In that case, use a thicker spacer between the magnet and the door to reduce the shunt.

Boiler

I tried swapping out the magnets per your suggestion. Same result-no function near the door.  I just ordered a switch that has an operational gap of 1 1/4 inch. I'm curious to see if the stronger magnet will work. I won't attach it with metal screws and I'll use something as a spacer to help it.
I'll let you know how it works out.
Thanks.