Low voltage switched light won't turn off


  #1  
Old 02-10-16, 05:40 PM
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Low voltage switched light won't turn off

Hi All,

I recently bought a house built in the 50's that has several low voltage light switches that look like this:

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https://www.dropbox.com/s/ap8a8lptoq...0_HDR.jpg?dl=0

I cannot turn off one of the hallway lights and a couple of outdoor flood light. An electrician came out and told me the transformer is bad and wants $400 to fix the lights or rewire for $1800. Replacing the transformer seems easy so I'm going to attempt to do it myself. The electrician did not come across as trustworthy so here I am hoping to get a second opinion from the wisdom of the crowd

My questions:

1) Do you think he is right that the replacing the transformer would fix the issue?
2) Is this the transformer?

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https://www.dropbox.com/s/fj80vd90ti...9_HDR.jpg?dl=0

Any suggestions are welcome.

Thanks!

Johnny
 
  #2  
Old 02-10-16, 06:34 PM
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I believe that thing is a GE RR-7 relay. Is the fix as simple as replacing it?

https://www.dropbox.com/s/bn32zyq1cn...2_HDR.jpg?dl=0
 
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Old 02-10-16, 07:22 PM
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Welcome to the best DIY forum on the Internet.

Yes, what you have pictured in the electrical box is the relay. It may, or may not, be bad. Somewhere in the house is a transformer that outputs 24 volts AC. It may have a rectifier connected to the output, some do and some don't. It is also possible the switch itself is bad.

Are all, or most of your lights controlled by similar low-voltage switches? If none of them can change state, on to off or off to on, the likely problem will be with the transformer, the 120 volt power to the transformer or the rectifier after the transformer if your system has the rectifier. The transformer can be mounted almost anywhere but near the main electrical fuse or circuit breaker panel is common.

How well versed in electrical troubleshooting are you? Do you have a multimeter and know how to use it?
 
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Old 02-10-16, 08:13 PM
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To add if you have other low voltages switches that do work than it almost certainly not the transformer or, if present, rectifier. Normally there is only one transformer so if other LV switches work that is proof it is good.
 
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Old 02-10-16, 08:48 PM
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A few lights are controlled by low-voltage switches and none of them appears to be working (can't turn lights off).

I found these two boxes next to the circuit breaker panel. Which one is the transformer? Rectifier?

https://www.dropbox.com/s/pmqb6clxjs...7_HDR.jpg?dl=0
https://www.dropbox.com/s/bi2jq5aaaj...1_HDR.jpg?dl=0

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Thanks!

Johnny
 

Last edited by ray2047; 02-10-16 at 09:36 PM. Reason: Add images.
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Old 02-10-16, 09:36 PM
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You need to take the cover off the second one so we can see what is inside. http://www.doityourself.com/forum/li...rt-images.html
 

Last edited by ray2047; 02-11-16 at 08:27 AM.
  #7  
Old 02-11-16, 03:55 AM
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I had to download the picture and enlarge it to read what was stamped on the transformer and yes, that is the transformer for the lighting control. Use a multimeter set to AC volts and a range higher than 30. Check on the two exposed terminals for voltage, it should be about 24 volts. If not, check all your circuit breakers to make sure they are on. Best is to turn the CB completely off and then back to the on position. If you still have no voltage at the transformer connections you will need to replace the unit. Just about any transformer with a 24 volt nominal AC output will do, it doesn't have to be a GE model.

Follow those wires and see where they go.

Oh, I'm also curious about the second item pictured. Please remove the screw and cover and post a picture of that.
 
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Old 02-12-16, 11:43 PM
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Inside of metal box:

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So is this box for the door bell or the other one?

Thanks,

Johnny
 
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Old 02-13-16, 12:22 AM
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As Furd wrote your original first picture is the transformer.

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Here is an online link to it. GE Low Voltage Transformer RT-1 115V for Indoor Lighting in Older Home It is discontinued but any transformer with a 120 volt primary and 24 volt secondary such as used for air conditioning controls should work so long as it is 40va (volt amps) or greater.

First though check it with a multimeter. Check both for 24 volts ac at the secondary and 120 volts at the primary. The transformer is mounted to a plate. Remove the plate to access the primary connections. 120 volts behind the plate. Use extreme caution when removing.



(The bottom picture is a buzzer. Edit: No,it is a relay.)
 

Last edited by ray2047; 02-13-16 at 12:52 AM.
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Old 02-13-16, 12:43 AM
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(The bottom picture is a buzzer.)
Actually, it is a relay, and a fairly heavy duty model. I have no idea what it is for.
 
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Old 02-17-16, 01:24 PM
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Hope everyone had a good 3 day weekend

I replaced the GE RR-7 relay and that did not fix the issue. I think the problem is with the old GE RT-1 transformer. I remember when the lights were working I would hear a clicking sound with the transformer when I hit the light switch. Now I don't hear it anymore -- thoughts?
 
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Old 02-17-16, 01:33 PM
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As was mentioned several times...... did you check the transformer ?
The transformer is shown quite clearly in post 9. Use a voltmeter set to AC volts to check it.
 
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Old 02-17-16, 03:15 PM
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I haven't used a multimeter in over 20 years. Can someone give me a quick tutorial?Name:  20160217_141322_HDR.jpg
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Old 02-17-16, 04:08 PM
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Looks like I'm getting between 31 and 32 Volts.

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Old 02-17-16, 04:21 PM
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Check the voltage at the switch and relay while someone presses the switch.
 
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Old 02-17-16, 05:06 PM
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Getting 29.6 at the switch. I'll test the relay reading and report back later.
 
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Old 02-17-16, 05:34 PM
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It could be a stuck relay.
 
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Old 10-10-16, 07:54 PM
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Update on this issue: Even after replacing the relay and low-voltage transformer, the issue still persists. I'm at wit's end...any other ideas, anyone?? Thanks!
 
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Old 10-10-16, 09:04 PM
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The wiring is pretty much straightforward but there is a diode in the mix. Shown circled in pink.
It may be shorted.

Have you come across it ?

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