Powerstealing thermostat wiring


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Old 02-11-07, 04:40 PM
C
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Powerstealing thermostat wiring

Hello. I am having trouble wiring a Trane powerstealing-type thermostat to a gas furnace in my garage. The furnace has R, W, and C terminals. My old mercury thermostat uses two wires (R and W). The Trane thermostat instructions say to wire a 360 ohm, 5 watt resistor across the W and C terminals on the furnace and wire the R and W to the thermostat (just like the old mercury one). There is no C terminal on the Trane thermostat.

The trouble is that when the Trane thermostat calls for heat, the furnace switches on for a second, then switches off and the thermostat power cycles.

I have tried wiring without the resistor and the same thing happens.

Thanks very much for any help. I am thinking that I probably need to get a different electronic thermostat--one with a C connection (or batteries).
 
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Old 02-11-07, 06:20 PM
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Cool

I'm not familiar with the Trane power stealers. The honeywells I have used in the past gets the resistor between R & W at the tstat, if there was R & C at the stat, I wouldn't have needed the resistor. At least if I remember correctly. I haven't used one in some time, I just use the battery powered digital stats. My recent favorite is the Lux PSP511LA. It's a 5/2 programmable, easy to program and has adjustable cycle rates & backlit panel.
 
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Old 03-01-07, 12:40 PM
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Thanks for the help. It turns out that for this application, it required two resistors. One between W and C and another between Y and C, even though Y is not used in this application.
 
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Old 03-01-07, 01:04 PM
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Wink

What is wrong with the old tstat and just R & W wires??? C is just common
 
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Old 03-01-07, 01:12 PM
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The old tstat was functional with just R and W. The problem with it was lack of control capability.
 
 

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