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#62607 - 02/20/06 06:10 PM low voltage switching
luckyshadow Offline
Registered: 01/04/05
Posts: 305
Loc: Maryland USA
I am going to look at a persons house that was built in the 70's. It has low voltage light switching. From what I am told the relays are located in the attic. It seems that some relays will " stick" in the summer when the attic is very hot.( It's not the same relays every time either)There is never a problem during the winter /fall/spring. The homeowner doesn't want to rewire the switches either. Another Electrician suggested that I try and make sure the relays are located together and maybe install a stat controlled fan to blow across them to try and cool them. Maybe try locating them close to the gable vent with a fan blowing inward and another on the other end blowing out; cooling the attic at the same time. Have any of you ever dealt with this type of system? Any ideas / suggestions are welcome
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#62608 - 02/20/06 06:37 PM Re: low voltage switching
JoeTestingEngr Offline
Registered: 11/04/05
Posts: 781
Loc: Chicago, Il.
I helped my brother build his home with a low voltage lighting panel using GE 24V RR7 relays. This panel is located in a basement so it doesn't go through high temperature excursions. I might look into installing a peltier effect module if I ran into the situation you describe. I say this because I could use the module to reduce the inner panel temp below ambient in the summer, then warm it above ambient in the winter. The modules are becoming quite popular in coolers these days. It would be a simple matter to come up with a control scheme with upper and lower limits.
#62609 - 02/20/06 07:47 PM Re: low voltage switching
Radar Offline
Registered: 04/30/04
Posts: 349
Loc: Los Angeles, CA
There's some relatively older neighborhoods around the LA area that were built in the 40's that use low voltage switching. Years ago I did a couple of service calls on these. These were somewhat unusual in that the relays were not located together but were distributed throughout the house. For instance, a switched light outlet would have the relay stuck in a KO in the outlet box - HV wires inside the box and LV wires out in the attic space.

I did not run into the situation you described (sticky relays)but I did replace a few burned out relays and defective switches. There was an Ace Hardware store in the neighborhood that stocked relays and switches and sold them to all the neighbors for outrageous prices.

If you discover all the relays in a common location, there is some benefit to that. As I understand it, the downside to that is being able to hear the relays all operate at the same location (i.e. if the relay panel is located right above the living room). However, it sure would be easier to work on.

Good luck, and please report back your findings.

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#62610 - 02/20/06 07:59 PM Re: low voltage switching
Lostazhell Offline
Registered: 02/21/04
Posts: 1428
Loc: Bakersfield, CA (Originally Or...
Maybe give these guys an email...


They made most of the systems I've run into around LA and San Diego... Although some of the older ones were made by Bryant, GE, or Sierra.
#62611 - 02/20/06 09:07 PM Re: low voltage switching
livetoride Offline
Registered: 01/11/05
Posts: 109
Loc: san diego ca usa
Check for sticking switches. If they have pilot lights I have seen the small xformers for the pilot lights short and cause sticking. Most of the time there is a master switch panel, individual switches that will operate all the switches (most of the time the master BR). Happy hunting. Rod

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